WO2007083897A1

WO2007083897A1 - Digital broadcasting system and method of processing data

Info

Publication number: WO2007083897A1
Application number: PCT/KR2007/000010
Authority: WO
Inventors: Hyoung Gon Lee; In Hwan Choi; Kyung Won Kang
Original assignee: Lg Electronics Inc.
Priority date: 2006-01-20
Filing date: 2007-01-02
Publication date: 2007-07-26

Abstract

A digital broadcast system is disclosed. The known data, which is identified by the transmitting/receiving ends, is inserted to a particular place in data region, to which the enhanced data is transmitted, and then transmitted to the receiving end. The receiving end uses the known data when performing modulation and equalization. Therefore, receiving performance of the receiving system can be enhanced in circumstances in which channels significantly vary and there is serious noise. The system initializes a memory of a Trellis encoder at the beginning part of the known data stream, and performs additional encoding, based on block coding for the enhanced data at the transmitting end, using the initialization, thereby increasing its encoding performance.

Description

DIGITAL BROADCASTING SYSTEM AND METHOD OF

PROCESSING DATA

Technical Field

[1] The present invention relates to a digital telecommunication system, and more particularly, to an apparatus and a method that are used for transmitting and receiving digital broadcast programs. Background Art

[2] Presently, the technology for processing digital signals is being developed at a vast rate, and, as a larger number of the population uses the Internet, digital electric appliances, computers, and the Internet are being integrated. Therefore, in order to meet with the various requirements of the users, a system that can transmit diverse supplemental information in addition to video/audio data through a digital television channel needs to be developed.

[3] Some users may assume that supplemental data broadcasting would be applied by using a PC card or a portable device having a simple in-door antenna attached thereto. However, when used indoors, the intensity of the signals may decrease due to a blockage caused by the walls or disturbance caused by approaching or proximate mobile objects. Accordingly, the quality of the received digital signals may be deteriorated due to a ghost effect and noise caused by reflected waves. However, unlike the general video/audio data, when transmitting the supplemental data, the data that is to be transmitted should have a low error ratio. More specifically, in case of the video/ audio data, errors that are not perceived or acknowledged through the eyes or ears of the user can be ignored, since they do not cause any or much trouble. Conversely, in case of the supplemental data (e.g., program execution file, stock information, etc.), an error even in a single bit may cause a serious problem. Therefore, a system highly resistant to ghost effects and noise is required to be developed.

[4] The supplemental data are generally transmitted by a time-division method through the same channel as the video/audio data. However, with the advent of digital broadcasting, digital television receivers that receive only video/audio data are already supplied to the market. Therefore, the supplemental data that are transmitted through the same channel as the video/audio data should not influence the conventional receivers that are provided in the market. In other words, this may be defined as the compatibility of broadcast system, and the supplemental data broadcast system should be compatible with the broadcast system. Herein, the supplemental data may also be referred to as enhanced data. Furthermore, in a poor channel environment, the receiving performance of the conventional receiver may be deteriorated. More specifically, resistance to changes in channels and noise is more highly required when using portable and/or mobile receivers. Disclosure of Invention

Technical Problem

[5] Accordingly, the present invention is to provide a digital broadcasting system that is suitable for transmitting supplemental data and that is highly resistant to noise.

[6] The present invention also is to provide a digital broadcast system and a data processing method, which are capable of inserting known data, which is previously known in transmitting/receiving ends, into a certain region of data interval to transmit it thereto, thereby enhancing receiving performance.

[7] The present invention also is to provide a digital broadcast system and a processing method, which are capable of performing added block encoding/decoding for enhanced data, thereby enhancing transmitting/receiving performance. Technical Solution

[8] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method of processing data in a transmitting system includes composing enhanced data packets including at least one of enhanced data having information and known data previously determined in transmitting/receiving ends, and multiplexing the enhanced data packets with main data packets, determining a place of known data for initializing a memory of a post- Trellis encoder at a start portion of known data stream in the enhanced data packet, on the basis of an output sequence of interleaved data, inserting a plurality of RS parity place holders to the enhanced data packets, such that the plurality of RS parity place holders are outputted later than the known data for initialization, on the basis of the output sequence of interleaved data, and performing data interleaving for known data on the insertion, performing additional encoding, based on block coding fashion, for only enhanced data in the enhanced data packets which are outputted after performing data interleaving, and outputting the remaining data which has not undergone the additional encoding, and performing Trellis encoding on the data outputted from the step and then outputting it.

[9] In another aspect of the present invention, a transmitting system includes an packet formatter/multiplexer, an RS parity place holder inserting/interleaving unit, and an enhanced encoding unit. The packet formatter/multiplexer may multiplex main data packets with enhanced data packets to output the multiplexed result, in which the enhanced data packets includes at least one of enhanced data having information and known data previously determined in transmitting/receiving ends. The RS parity place holder inserting/interleaving unit may insert a plurality of RS parity place holders to the enhanced data packets outputted from the packet formatter/multiplexer, to perform data interleaving. The enhanced encoding unit may perform additional encoding, based on block coding fashion, for only enhanced data after performing data interleaving, perform data de-interleaving, and remove RS parity place holders.

[10] The system may further include a non-systematic RS parity place holder insertion unit/data interleaver, a Trellis encoder, a compatible processor, and a transmitting unit. The non-systematic RS parity place holder insertion unit/data interleaver may insert a plurality of non-systematic RS parities or RS parity place holders in the output data of the enhanced encoding unit to perform data interleaving, and output the result of the data interleaving to perform Trellis encoding. The Trellis encoder may perform Trellis encoding after performing memory initialization when the data after performing data interleaving is known data and is a start part of successive known data stream, and output the encoded result, in which the Trellis encoder can perform initialization. The compatible processor may re-calculate a non-systematic RS parity based on output of the non- systematic RS parity place holder insertion unit and the Trellis encoder, such that the non-systematic RS parity or the RS parity place holder, which is inputted by the Trellis encoder, is substituted with the re-calculation result. The transmitting unit may insert synchronous symbol to the output of the Trellis encoder, and modulate it to transmit the modulation result thereto.

[11] In yet another aspect of the present invention, a receiving system includes a demodulating/equalizing unit, an enhanced decoder, and a known data detecting/ generating unit. The demodulating/equalizing unit may perform demodulation and channel equalization as signals transmitted from the digital broadcast system are received through a tuning operation, and known data information is applied to the received signals. The enhanced decoder may perform soft determination decoding and decode of block coding fashion as known data information is applied to the channel equalized enhanced data. The known data detecting/generating unit may detect the known data information, which is inserted in the transmitting end, from signals before demodulation or after modulation, and output the detection result to the demodulating/ equalizing unit and the enhanced decoder.

[12] It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Advantageous Effects

[13] The digital broadcast system and the process method thereof according to the present invention have advantages in that errors hardly occur when enhanced data are transmitted through channels and they also are compatible with the conventional receivers. Also, the digital broadcast system and the process method thereof can receive enhanced data without errors through channels in which ghost images and noise are a serious problem, compared with the conventional system.

[14] Also, as known data are inserted to a particular place in data region and then transmitted, receiving performance of a receiving system, whose channel variation is serious, can enhanced.

[15] Especially, the present invention initializes a memory of a Trellis encoder at the beginning part of the known data stream, and performs additional encoding, based on block coding for the enhanced data at the transmitting end, using the initialization, thereby increasing its encoding performance. Also, the receiving end performs soft determination decoding for enhanced data, which is encoded on the basis of block coding, thereby increasing its decoding performance.

[16] The present invention is more effective as it is applied to portable and mobile receivers whose channels vary significantly. Also, the present invention remarkably shows its effect in receivers which require robustness against noise. Brief Description of the Drawings

[17] FIG. 1 illustrates a schematic block diagram of a transmitting system according to an embodiment of the present invention;

[18] FIG. 2 illustrates a detailed block diagram of a Trellis encoder of FIG. 1, according to an embodiment of the present invention;

[19] FIG. 3 illustrates a schematic block diagram for a structure of a data interleaver of

FIG. 1;

[20] FIG. 4 illustrates a view for describing a sequence of output of a data interleaver in the transmitted frame;

[21] FIG. 5 illustrates data configuration at the input end of the data interleaver as known data is inserted thereto, according to the present invention;

[22] FIG. 6 illustrates data configuration at the output end of the data interleaver as known data is inserted thereto, according to the present invention;

[23] FIG. 7 illustrates a schematic block diagram of an embodiment of the enhanced encoder according to the present invention;

[24] FIG. 8 illustrates a schematic block diagram of another embodiment of the enhanced encoder according to the present invention;

[25] FIG. 9 illustrates a schematic block diagram of an embodiment of the enhanced decoder according to the present invention;

[26] FIG. 10 illustrates a schematic block diagram of another embodiment of the enhanced decoder according to the present invention; [27] FIG. 11 illustrates a schematic block diagram of a demodulating unit included a receiving system according to an embodiment of the present invention;

[28] FIG. 12 illustrates a block diagram of a transmitting system according to another embodiment of the present invention;

[29] FIG. 13 illustrates a block diagram showing a general structure of a demodulating unit within a receiving system according to another embodiment of the present invention;

[30] FIG. 14 illustrates a block diagram showing the structure of a receiving system according to an embodiment of the present invention; and

[31] FIG. 15 illustrates a block diagram showing the structure of a receiving system according to another embodiment of the present invention. Best Mode for Carrying Out the Invention

[32] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[33] The terminologies disclosed the present application are widely used in this fields of the present invention. However, some of them are defined by the inventors. In this case, the newly defined terminologies are described in detail in the following description. Therefore, the terminologies in the present invention will be understood on the basis of the disclosure of the present application.

[34] Enhanced data in the present application may be any of application program execution files, data having information, such as stock information, etc., and video/ audio data. Known data may be data which is previously known in transmitting/ receiving ends, based on a protocol. Main data is indicative of data which can be received by the conventional receiving systems, including video/audio data.

[35] The present invention serves to multiplex the enhanced data having information and the known data known in the transmitting/receiving ends, and to transmit them, to enhance receiving performance of a receiving.

[36] Especially, the present invention serves to initialize a memory in a Trellis encoder at the beginning portion of the known data stream, and apply a block encoding for the enhanced data at the transmitting/receiving ends, using the initialization characteristics, to perform additional encoding/decoding.

[37] FIG. 1 illustrates a schematic block diagram of a digital broadcast transmitting system according to an embodiment of the present invention. The digital broadcast transmitting system includes a pre-processor 101, a packet formatter 102, a packet multiplexer 103, a data randomizer 104, a scheduler 105, a post-processor 110, an RS encoder/Non-systematic RS parity holder inserter 121, a data interleaver 122, a Trellis encoding unit 123, a compatible processor 130, a frame multiplexer 140, and a transmitting unit 150.

[38] Main data is outputted to the multiplexer 103, based on transport packet units.

Enhanced data is outputted to the pre-processor 101. The pre-processor 101 performs pre-processes, such as additional error correction code, interleaving, insertion of null data, etc., regarding the enhanced data, and then outputs it to the packet formatter 102.

[39] The packet formatter 102 includes at least one of the preprocessed enhance data and predetermined known data (or known data place holder), under control of the scheduler 105, and adds a 4-byte MPEG header thereto to form a MPEG packet based on 188 bytes. After that, the MPEG packet is outputted to the packet multiplexer 103.

[40] The packet multiplexer 103 serves to perform time multiplexing, based on transport stream (TS) packet unit, for the main data packets and the enhanced data packet, according to pre-defined multiplexing method, under the control of the scheduler 105. Here, the main data packets and the enhanced data packet are formed on the basis of 188 byte unit.

[41] Namely, the scheduler 105 generates a control signal such that the packet multiplexer 103 multiplexes main data packets and enhanced data packets, and then output them to the packet multiplexer 103. The packet multiplexer 103 receiving the control signal multiplexes the main data packets and the enhanced data packets, based on TS packet units, and outputs the multiplexed result.

[42] The output of the packet multiplexer 103 is inputted to the data randomizer 104.

The data randomizer 104 removes an MPEG synchronous byte from the input packet and randomizes the remaining 187 bytes using pseudo random bytes, which are generated therein, to output them to the post-processor 110.

[43] The post-processor 110 includes an RS encoder/Non-systematic RS parity place holder inserter 111, a data interleaver 112, an enhanced encoder 113, a data de- interleaver 114, and an RS byte remover 115.

[44] The RS encoder/Non-systematic RS parity place holder inserter 111 performs a systematic RS encoding or a non-systematic RS parity holder insertion for the randomized data.

[45] Namely, when the 187 byte packet, which is outputted from the data randomizer

104, is main data packet, the RS encoder/Non-systematic RS parity place holder inserter 111 performs systematic RS encoding, which is identical to that of a conventional broadcast system, and adds a parity of 20 bytes to the end of the 187 byte data, to output it to the data interleaver 112.

[46] On the other hand, when the 187 byte packet, which is outputted from the data randomizer 104, is enhanced data packet, the RS encoder/Non-systematic RS parity place holder inserter 111 inserts RS parity place holder, which is composed of null data of 20 bytes, in the packet, and inserts data of the enhanced data packet to places of the remaining 187 byte packet, correspondingly, to output them to the data interleaver 112.

[47] The data interleaver 112 performs data interleaving for the output of the RS encoder/Non-systematic RS parity place holder inserter 111 to output it to the enhanced encoder 113.

[48] The enhanced encoder 113 performs additional 1/2 encoding for only the enhanced data, which is outputted from the data interleaver 112, to output it to the data de- interleaver 114. The data de-interleaver 114 performs data de-interleaving for the inputted data to output it to the RS byte remover 115. Here, the data de-interleaver 114 performs a reverse process of the data interleaver 112.

[49] Data interleaving of the data interleaver 112 and encoding of the enhanced encoder

113 will be described later.

[50] The RS byte remover 115 removes the 20 byte parity which is added in the RS encoder/Non-systematic RS parity place holder inserter 111. Here, when the inputted data is main data packet, the last 20 bytes of the 207 bytes are removed. When the inputted data is the enhanced data packet, parity place holders of 20 bytes of 207 bytes are removed, in which the parity place holders are inserted thereto to perform non- systematic RS encoding. Namely, such procedures for the enhanced data serve to recalculate parity because original data is changed by the enhanced encoder 113.

[51] The output of the RS byte remover 115 is inputted to the RS encoder/

Non-systematic RS parity holder inserter 121. When the 187 byte packet, which is outputted from the RS byte remover 115, is main data packet, similar to the RS encoder/Non-systematic RS parity place holder inserter 111, the RS encoder/ Non-systematic RS parity holder inserter 121 performs systematic RS encoding, which is identical to a conventional broadcast system, and inserts parity of 20 bytes to the end of the data of 187 bytes.

[52] When the packet is enhanced data packet, byte places of 20 parities are determined in the packet to perform non-systematic RS encoding in the rear end of the compatible processor 130. After that, parities obtained after non-systematic RS encoding may be inserted in the determined byte places of parities or null byte instead of the parities may be inserted thereto. The bytes in the enhanced data packet are sequentially inserted in the places of the remaining 187 bytes. The null byte is determined by a certain value. The null byte is substituted with a parity value which is calculated in the non-systematic RS encoder 133 of the compatible processor 130.

[53] Therefore, the null byte serves to secure a place of parity byte of non-systematic RS code. The output of the RS encoder/Non-systematic RS parity holder inserter 121 is outputted to the data interleaver 122. Also, when the packet is enhanced data packet, the output is inputted to the compatible processor 130 to re-calculate parity.

[54] The data interleaver 122 performs interleaving for the inputted data, like the interleaving rule of data interleaver 112.

[55] FIG. 3 illustrates a schematic block diagram for a structure of a data interleaver

(122 or 112) of FIG. 1, or a convolution interleaver of which branch number is 52 and the number M of a unit memory byte is 4.

[56] As shown in FIG. 3, when a first byte is inputted thereto, it is outputted through the first branch, and a second byte is inputted thereto through a second branch. Therefore, a value before 52*4 bytes is outputted.

[57] FIG. 4 illustrates a view for describing a sequence of output of a data interleaver of

FIG. 3 in the transmitted frame. The data is sequentially inputted from the lower part to the upper part, based on segment units, in which bytes in the segment are sequentially inputted thereto from left to right. The numerals of FIG. 4 are indicative of the output sequence of the data interleaver. The data interleaver is operated on the basis of unit of 52 segments.

[58] The output of the data interleaver 122 is inputted to the Trellis encoding unit 123.

The Trellis encoding unit 123 encodes the inputted 2 bits to 3 bits to output it thereto. The output of the Trellis encoding unit 123 is inputted to the frame multiplexer 140. The frame multiplexer 140 inserts a field synchronization bit and a segment synchronization bit to the output of the Trellis encoding unit 123 to transmit it to the transmitting unit 150. The transmitting unit 150 includes a pilot inserter 151, a modulator 152, and an RF converter 153. Since the transmitting unit 150 is operated as the conventional transmitter, its detailed description will be omitted.

[59] In order to use the output data of the Trellis encoding unit 123 as the known data which was defined in the transmitting/receiving ends, it is necessary to initialize a memory of the Trellis encoding unit 123 before the known data inserted in the enhanced data packet is processed. The input of the Trellis encoding unit 123 is needed to perform substitution for the initialization. RS parity affected by the changed data is re-calculated to be substituted with the original parity data. Such a procedure is performed in the compatible processor 130.

[60] FIG. 2 illustrates a detailed block diagram of a Trellis encoding unit 123 of FIG. 1, which is initializable.

[61] The Trellis encoding unit 123 which is initializable includes a byte-symbol converter 201, a multiplexer 202 for selecting one of inputs thereof, a Trellis encoder 203 for inputting the selected input from the multiplexer 202, and a Trellis state initialization controller 204 for initializing the Trellis encoder 203.

[62] Such Trellis encoding unit is operated as follows. The byte-symbol converter 201 inputs interleaved data based on byte units to convert it to interleaved data based on symbol units, and then performs 12-way interleaving for the data to output it to the multiplexer 202.

[63] For a normal case, the output of the byte-symbol converter 201 is selected by the multiplexer 202 such that the output can be transmitted to the Trellis encoder 203 through the multiplexer 202. On the other hand, when the interleaved data is known data and the known data is the beginning portion of the successively inputted known data stream, it is necessary to initialize the Trellis encoder 203, since the Trellis encoder 203 has a memory and thus its present output is affected by present and past inputs. Therefore, in order to output a predetermined signal at a certain time, the memory of the Trellis encoder 203 must be initialized at a certain value.

[64] When the memory of the Trellis encoder 203 requires initialization thereof, a part of the known data is substituted with an initialization data to be outputted to the Trellis encoder 203. Afterwards, the memory of the Trellis encoder 203 is initialized to a predetermined value based on the initialization data. Therefore, from the time point of the initialization, the output of the Trellis encoder 203 can be the known data which is encoded to comply with the transmitting/receiving ends.

[65] The Trellis state initialization controller 204 for initializing the Trellis encoder 203 inputs a memory value of the Trellis encoder 203 to generate initialization data to be inputted to the Trellis encoder 203 and then outputs it to the compatible processor 130.

[66] Namely, the Trellis encoder 203 is operated such that upper bit of the two bits composing a symbol is encoded to a single bit using a single memory to be outputted, and the lower bit is encoded to two bits using the two memories to be outputted. Here, when the input data is known data and thus the known data is the beginning of the successively inputted known data stream, the memories must be initialized to output the inputted data as desired known data, after the inputted data undergoes Trellis encoding. Therefore, when the memory of the Trellis encoder 203 requires initialization, the Trellis state initialization controller 204 generates initialization data according to a present state and a desired initialization state of the memory, and then outputs it to the multiplexer 202.

[67] The initialization data is formed by 4 bits, or two symbols. Here, there may be a plurality of the Trellis encoder 203, for example, 12. The 12 bytes outputted from the multiplexer 202 are sequentially inputted to the each of the Trellis encoders 203. Here, the beginning 4 bits of each byte, or two symbols, can be initialization data. Namely, the initialization controller 204 generates initialization data and then outputs it to the multiplexer 202 and the compatible processor 130, in which the initialization data initializes the memory of the Trellis encoder 203 in first two symbol intervals at which the known data symbol stream is started.

[68] The compatible processor 130 inputs the output of the RS encoder/Non- systematic RS parity holder inserter 121 and the output of the initialization controller 204 and then generates non-systematic 20 byte parity to be outputted to the multiplexer 202 of the Trellis encoding unit 123.

[69] Namely, since the memory of the Trellis encoding unit 123 is initialized by new data but not by data which is interleaved in the data interleaver 122, RS parity must be re-generated to substitute the original parity data. Such procedure is performed in the compatible processor 130.

[70] The compatible processor 130 includes a packet buffer 131, a symbol-byte converter 132, a non- systematic RS encoder 133, and a byte-symbol converter 134.

[71] Namely, the output of the RS encoder/Non-systematic RS parity holder inserter 121 is inputted to the data interleaver 122 and the packet buffer 131. The initialization data of the initialization controller 204 is inputted to the multiplexer 202 of the Trellis encoding unit 123 and the symbol-byte converter 132 of the compatible processor 130.

[72] Here, since the RS encoder/Non-systematic RS parity holder inserter 121 inputs and outputs its input and output based on byte unit, the symbol-byte converter 132 converts the initialization data of symbol unit to the initialization of byte unit and then outputs it to the packet buffer 131.

[73] The packet buffer 131 inputs the byte output from the RS encoder/Non-systematic

RS parity holder inserter 121 and the byte output from the symbol-byte converter 132 to temporarily store them and then outputs them to the non- systematic RS encoder 133. The non-systematic RS encoder 133 inputs the byte output from the packet buffer 131 to generate parity of non-systematic 20 bytes and then outputs the parity based on symbol unit to the multiplexer 202 of the Trellis encoding unit 123 through the byte- symbol converter 134.

[74] When the inputted data, which is interleaved and then converted to symbols, is the beginning of known data stream, the multiplexer 202 selects the initialization symbol of the initialization controller 204 instead of the inputted symbol, and then outputs it. When the inputted data is RS parity or parity place holder, the multiplexer 202 selects the output symbol of the symbol-byte converter 134 of the compatible processor 130 instead of the inputted symbol. Except for the above cases, the multiplexer 202 selects inputted data, which is interleaved and then converted to symbol, and then outputs it to the Trellis encoder 203. Namely, substitution of initialization symbol occurs at places of first two symbols in the known data stream, to be inputted to the Trellis encoder 203. Also, substitution of parity symbol, which is re-calculated in the compatible processor 130, occurs at the parity place of each packet, to be outputted to the Trellis encoder 203. Especially, when the RS encoder/Non-systematic RS parity holder inserter 121 does not insert a non-systematic RS parity to the enhanced data packet but instead inserts a null byte, the compatible processor 130 calculates non-systematic RS parity of the enhanced data packet, regardless of initialization of the Trellis encoder, to perform substitution using the calculation result.

[75] The Trellis encoder 203 performs Trellis encoding for the data outputted from the multiplexer 202, based on symbol unit, and then outputs it to the frame multiplexer 140. Also, the Trellis encoder 203 outputs its memory state to the initialization controller 204.

[76]

[77] Known data insertion and Non-systematic RS parity place

[78] The following is a description for insertion of known data and setting of a non- systematic RS parity place.

[79] FIG. 5 illustrates data configuration at the input end of the data interleaver as known data is inserted thereto. FIG. 6 illustrates data configuration at the output end of the data interleaver as the data of FIG. 5 is inserted thereto.

[80] Namely, a receiving sequentially inputs data from the output end of the data interleaver outputted as the data interleaver output. Also, known data must be successively inputted thereto in response to the sequence of number of FIG. 4, such that the receiving can receive timely successive known data. As shown in FIG. 6, in order that a single data segment, which is received in the receiving, is all known data, the single data segment is divided into 52 byte units, as shown in FIG. 5. Afterwards, the known data is inserted thereto at a place of data segment at each 52 byte unit. Here, the beginning part of the known data stream needs initialization byte. Therefore, when the place of known data is determined in the data segment, a place of the initialization byte is determined as the place at which normal data ends and the known data is started, from the point of view of the output end of the data interleaver. When the place of initialization byte of the known data is determined, the place of a non-systematic RS parity byte can be determined. The place is preferably located such that the parity bytes can be outputted latter than the initialization bytes, from the point of view of the output end of the data interleaver. Namely, for a single segment, as shown in FIG. 4, the lower order bit is outputted earlier from the data interleaver than the larger one. Therefore, the RS parity is preferably located later than the sequence number of the initialization bytes.

[81] The following is another embodiment of a method for inserting known data thereto.

As shown in FIG. 6, when the known data is inserted after the MPEG header in a first segment, from the point of view of the output end of the data interleaver, or the known data is inserted from after the MPEG header to the end of the segment, since MPEG header bytes of a second segment have a certain value for enhanced data packets, the MPEG header bytes can be regarded as continuation data.

[82] As such, the present invention serves to perform substitution of data to initialize the memory of the Trellis encoder to a predetermined initial state when the known data stream is started. Also, the present invention serves to perform non-systematic RS encoding for enhanced data packets to keep compatibility with conventional receivers by the substituted data or to insert known data in conventional systematic RS parity regions.

[83] enhanced encoder

[84] On the other hand, the enhanced encoder 113 performs additional encoding for enhanced data and then outputs it thereto. Namely, when the output of the data in- terleaver 112 is main data, the enhanced encoder 113 does not change MPEG header byte, which is added in the packet formatter 102, or RS parity or RS parity place byte, which are added to the enhanced data packet in the RS encoder/Non-systematic RS parity place holder inserter 111, and outputs them thereto.

[85] Also, similar to main data, the known data is outputted thereto without additional encoding procedure. However, the method for processing the known data may be different from that for processing the main data.

[86] For example, there is a method for outputting known data which is generated in a symbol region, instead of a known data place holder, in the enhanced encoder 113, in a state where the known data place holder is inserted in the packet formatter 102. Also, there is another method in which the enhanced encoder 113 does not change data but outputs the data, in state where the known data is inserted in the packet formatter 102.

[87] The former method is described through FIG. 7 and FIG. 9, and the latter method is described through FIG. 8 and FIG. 10.

[88] Firstly, as shown in FIG. 7, the enhanced encoder 113 includes a demultiplexer 610, a buffer 620, a U/C encoding unit 630, and a multiplexer 640.

[89] The U/C encoding unit 630 serves to encode U bit of the enhanced data to C bit and then to output it thereto. For example, when 1 bit of the enhanced data is encoded to two bits to output it thereto, U is 1 and C is 2.

[90] The U/C encoding unit 630 includes a byte-bit converter 631, a U/C encoder 632, a block interleaver 633, and a bit-byte converter 634. The U/C encoder 632 is implemented with a 1/2 encoder. The U/C encoder 632 and the block interleaver 633 (which is optional) are defined as an enhanced encoder core in the present invention.

[91] As shown in FIG. 9, the demultiplexer 610 outputs its output to the buffer 620 when inputted data is main data, and to the U/C encoding unit 630 when the inputted data is enhanced data.

[92] The buffer 620 delays main data for a certain time, and then outputs it to the multiplexer 640. Namely, when main data is inputted to the demultiplexer 610, the buffer 620 is used to compensate time delay which is generated while the enhanced data is additionally encoded. Afterwards, the main data, whose time delay is controlled by the buffer 620, is transmitted to the data deinterleaver 114 through the multiplexer

640. [93] When the known data is inputted, the known data place holder is inserted thereto in the packet formatter 102. The multiplexer 640 of the enhanced encoder 113 selects the training sequence T instead of the known data place holder and then outputs it thereto.

Therefore, the known data can be outputted without additional encoding. [94] On the other hand, the byte-bit converter 631 of the U/C encoding unit 630 converts the enhanced data byte to enhanced data bits and then outputs them to the 1/2 encoder

632. The 1/2 encoder 632 encodes inputted one bit to two bits to output them thereto. [95] The 1/2 encoder 632 is implemented with a convolution encoder or a low density parity check (LDPC) encoder, etc., which can use block codes. Also, the 1/2 encoder

632 may selectively adopt a block interleaver 633 according to implementation objectives. [96] For example, assuming that one byte of the enhanced data is extended to two bytes as null bits are inserted among bits thereof in the pre-processor 101. The byte-bit converter 631 removes the null bits of inputted bytes and then outputs only effective data bits to the 1/2 encoder 632. [97] The 1/2 encoder 632 encodes one bit input to two bits, on the basis of block coding, and the block interleaver 633 inputs the two bits to perform block interleaving therefor. [98] The block interleaving is related to the total system performance and may be used in any interleavings, such as a random interleaving. [99] Here, the 1/2 encoder 632 performs encodings based on block units. The block size must be determined such that the block interleaver 633 can perform block interleaving. [100] According to the present invention, the block size can be determined by input format of the enhanced encoder 113, as shown in FIG. 6. [101] The following is a description for a method for determining block size with reference to the input format of FIG. 6. [102] FIG. 6 shows that the number of parts to initialize the memory of Trellis encoder is

5 when interleaving unit is 52 segments. In this case, it can be divided from one block into four blocks. [103] Namely, for high block code performance of FIG. 6, the block size can be preferably determined by the bit number of the enhanced data from first Trellis initialization to fifth Trellis initialization. [104] According to another embodiment, the block size can be determined by the bit number of the enhanced data from among the first Trellis initialization to third Trellis initialization. In this case, the enhanced data of one data interleaving unit, which must be encoded in the enhanced encoder 113, is divided into two blocks and then encoded.

Namely, the enhanced data among the first Trellis initialization and third Trellis ini- tialization is encoded on the basis of one block size, and the enhanced data among the third Trellis initialization and the fifth initialization is encoded on the basis of another block size.

[105] Also, according to a further embodiment, the block size can be determined as the bit number of the enhanced data between the first Trellis initialization and the second Trellis initialization. In this case, the enhanced data of one data interleaving unit, which must be encoded in the enhanced encoder 113, is divided into four blocks and then encoded.

[106] The enhanced data, which was used to determine the block size, must be additionally encoded in the enhanced encoder 113. Here, the enhanced data does not include the known data and non-systematic RS parity.

[107] The block size can be set with reference to the Trellis initialization, since data after

Trellis initialization is not affected by inputs before the initialization. Namely, since the enhanced data have limited lengths with reference to the data of the Trellis initialization, start and end of classified blocks are determined. Therefore, encoding performance of the enhanced data, which is performed in the block coding, can be further increased.

[108] The bit-byte converter 634 serves to convert output bits of the block interleaver 633 to bytes and then outputs them to the multiplexer 640.

[109] The multiplexer 640 selects main data outputted from the buffer 620, when the inputted data is main data, and enhanced data, which is encoded in the U/C encoding unit 630, when the inputted data is the enhanced data. Also, when the inputted data is known data place holder, the multiplexer 640 selects training sequence to output it to the deinterleaver 114.

[110] FIG. 7 illustrates a schematic block diagram of an embodiment of the enhanced encoder, and FIG. 8 illustrates a schematic block diagram of another embodiment of the enhanced encoder. FIG. 7 and FIG. 8 are different from one another, regarding a known data processing part. Namely, FIG. 8 is identical to FIG. 7 except that, when the inputted data is known data, the demultiplexer 660 outputs the known data to the buffer 670 such that the buffer 670 can delay a certain time and then output it to the deinterleaver 114 through the multiplexer 680. Therefore, the detailed description for FIG. 8 will be omitted.

[I l l] Such processes are performed under the assumption that the known data is already inserted in the enhanced data packet in the packet formatter 102.

[112] As such, the present invention serves to initialize the memory of the Trellis encoder at the beginning part of the know data stream and perform additional encoding for the enhanced data, based on block coding, using the initialization. Therefore, performance of the additional encoding for the enhanced data can be increased. [113] FIG. 9 illustrates a schematic block diagram of an embodiment of the enhanced encoder 113, and FIG. 10 illustrates a schematic block diagram of another embodiment of the enhanced encoder 113.

[114] Firstly, as shown in FIG. 9, the enhanced encoder 113 includes a demultiplexer 710, a buffer 720, an N-way encoder 730, and a multiplexer 740.

[115] The N-way encoder 730 includes an N-way interleaver 731, an N-way deinterleaver

733 and N enhanced encoding units 7321-732N, which are connected, in parallel, between the N-way interleaver 731 and the N-way deinterleaver 733.

[116] Each enhanced encoding unit includes a symbol-bit converter, an enhanced encoder core, and a bit-symbol converter. The enhanced encoder core includes a U/C encoder and a block interleaver. The U/C encoder is preferably implemented with a 1/2 encoder. The 1/2 encoder may use block codes of a convolution encoder or a low density parity check (LDPC) encoder. Also, the 1/2 encoder may selectively use a block interleaver according to implementation objectives.

[117] As shown in FIG. 9, when the inputted data is main data, the demultiplexer 710 outputs the main data to the buffer 720. When the inputted data is enhanced data, the demultiplexer 710 outputs the enhanced data to the N-way interleaver 731 of the N- way encoding unit 730.

[118] The buffer 720 delays main data for a certain time, and then outputs it to the multiplexer 740. Namely, when main data is inputted to the demultiplexer 710, the buffer 720 is used to compensate time delay which is generated while the enhanced data is additionally encoded. Afterwards, the main data, whose time delay is controlled by the buffer 720, is transmitted to the data deinterleaver 114 through the multiplexer 740.

[119] When the known data is inputted, the known data place holder is inserted thereto in the packet formatter 102. The multiplexer 740 of the enhanced encoder 113 selects the training sequence T instead of the known data place holder and then outputs it thereto. Therefore, the known data can be outputted without additional encoding.

[120] On the other hand, the N-way interleaver 731 converts the enhanced data bytes to symbols, such that each of the symbols can be distributed to corresponding enhanced encoding unit. Namely, the enhanced data of the demultiplexer 710 are formed into N divided symbol outputs by the N-way interleaver 731 of the N-way encoding unit 730.

[121] The N divided symbols are sequentially distributed to the N enhanced encoding units or non- sequentially distributed to the encoding units based on a pre-set interleaving sequence.

[122] For example, when N is 4, one byte is changed to 4 symbols. Therefore, the 4 symbols are distributed to the four enhanced encoding units, in sequence or in a predetermined interleaving sequence. Also, symbols located at the same places in each of the four bytes are distributed to 4 enhanced encoding units based on a predetermined sequence.

[123] The enhanced encoding units have the same structure, such that they can operate identically.

[124] Therefore one of the enhanced encoding units will be described in detail. Namely, the symbol-bit converter in the enhanced encoding unit inputs a symbol distributed from the N-way interleaver 731 to convert it to bits. Afterwards, a null bit of the bits is removed, such that only effective data bits can be outputted to the enhanced encoder core, in which the null bit is inserted thereto through null extension in the preprocessor 101.

[125] For example, let's assume that on byte of enhanced data is extended to two bytes as null bits are inserted among bits in the pre-processor 101. Then, the symbol-bit converter removes the null bits and outputs only effective data bits.

[126] The 1/2 encoder in the enhanced encoder core encodes one bit of input to two bits, based on block coding, and then outputs them thereto. The block interleaver inputs the output of the 1/2 encoder to perform block interleaving.

[127] Here, the block size for block coding or block interleaving is determined as the block size defined in FIG. 7 and FIG 8 is divided by the number of ways N of N-way interleaving. For example, the largest block size can be determined as the bit number of effective enhanced data is divided by N, in which the effective enhanced data is located among the first initialization to the last fifth initialization, of Trellis initialization to form known data as shown in FIG. 6. On the other hand, as described above, block interleaving having the block size may be used in any interleaving operations is related to the total system performance and may be used in any in- terleavings, such as a random interleaving.

[128] The output of the enhanced encoder core is converted to symbols in the bit-symbol converter and then outputted to the N-way deinterleaver 733. The N-way deinterleaver 733 performs deinterleaving for the symbols outputted from the respective enhanced encoding units and then outputs them to the multiplexer 740. Here, the N-way deinterleaver 733 performs a reverse operation of the N-way interleaver 731.

[129] When inputted data is main data, the multiplexer 740 selects the main data outputted from the buffer 720. When the inputted data is enhanced data, the multiplexer 740 selects the enhanced data outputted from the N-way encoding unit 730. Also, when the inputted data is known data place holder, the multiplexer 740 selects training sequence to output it to the data deinterleaver 114.

[130] FIG. 9 and FIG. 10 are different from one another, regarding a known data processing part. Namely, FIG. 10 is identical to FIG. 9 except that, when the inputted data is known data, the demultiplexer 760 outputs the known data to the buffer 770 such that the buffer 770 can delay a certain time and then output it to the deinterleaver 114 through the multiplexer 780. Therefore, the detailed description for FIG. 10 will be omitted.

[131] Such processes are performed under the assumption that the known data is already inserted in the enhanced data packet in the packet formatter 102.

[132] FIG. 11 illustrates a schematic block diagram of a demodulating unit included a receiving system according to an embodiment of the present invention, in which the digital broadcast receiving system receives data, which are transmitted from the digital broadcast transmitting system of FIG. 1, and performs modulation and equalization for the received data to restore original data.

[133] The demodulating unit includes a demodulator 801, an equalizer 802, a known sequence detector 803, an enhanced decoder 804, a data deinterleaver 805, an RS decoder/non-systematic RS parity remover 806, a derandomizer 807, a main data packet remover 808, a packet deformatter 809, and an enhanced data processor 810.

[134] Namely, the particular channel frequency tuned by a tuner outputs to the demodulator 801 and the known sequence detector 803.

[135] The demodulator 801 performs carrier restoring and timing restoring for the tuned channel frequency to generate a base band signal and then output it to the equalizer 802 and the known sequence detector 803.

[136] The equalizer 802 compensates distortion in the channel included in the demodulated signal and then outputs it to the enhanced decoder 804.

[137] Here, the known sequence detector 803 detects known data place, which is inserted in the transmitting end, from input/output data of the demodulator 801, and then outputs symbol stream of the known data, which is generated in the known data place, to the equalizer 802 and the enhanced decoder 804. Here, the input/output data of the demodulator 801 are indicative of data before or after performing demodulation. Also, the known sequence detector 803 outputs information to the enhanced decoder 804, such that enhanced data, which performs additional encoding through the enhanced decoder 804, can be discriminated from the main data, which does not perform additional encoding, and such that a beginning point of a block of the enhanced encoder core, which is discriminated by the Trellis initialization of FIG. 6, can be notified.

[138] The demodulator 801 enhances its modulation performance using the known data symbol stream when performing timing restoration or carrier restoration. The equalizer 802 enhances its equalization performance using the known data. The enhanced decoder 804 identifies the beginning and end of a block and restores data based on the identified result.

[139] Namely, the enhanced decoder 804 performs encoding for main data symbols and enhanced data symbols, which are outputted from the equalizer 802, to convert them to bytes and then outputs them to the deinterleaver 805. Such processes will be described in detail as follows.

[140] The deinterleaver 805 performs deinterleaving and outputs the deinterleaving result to the RS decoder/non-systematic RS parity remover 806. Here, the deinterleaver 805 performs a reverse operation of the data interleaver at the transmitting end. When the inputted packet from the RS decoder/non-systematic RS parity remover 806 is main data packet, systematic RS decoding is performed. When the inputted packet is enhanced data packet, non-systematic RS parity byte, which is inserted to the packet, is removed and then outputted to the derandomizer 807.

[141] The derandomizer 807 performs derandomizing for output of the RS decoder/ non-systematic RS parity remover 806 and then inserts MPEG synchronization byte to the front part of each packet to output it, based on 188 byte packet unit, thereto. Here, the derandomizer 807 operates a reverse operation of the randomizer.

[142] The derandomizer 807 outputs its output to a main MPEG decoder (not shown) and the main data packet remover 808, simultaneously. The main MPEG decoder performs decoding for only packet corresponding to the main MPEG, since the enhanced data packet is not used in a conventional receiver or has null or reserved PID. Therefore, the enhanced data packet is not used in the main MPEG decoder and is thus ignored.

[143] The main data packet remover 808 removes a main data packet of 188 byte unit from the output of the derandomizer 807 and outputs it to the packet deformatter 809. The packet deformatter 809 removes MPEG header of 4 bytes from the enhanced data packet which is outputted from the main data packet remover 808, in which the MPEG header of 4 bytes is inserted to the enhanced data packet by the formatter at the transmitting end. Also, the packet deformatter 809 removes bytes to which place holder (not enhanced data) is inserted at the transmitting end, for example place holders for known data, and then outputs them to the enhanced data processor 810. The enhanced data processor 810 performs a reverse operation of pre-processor 101 at the transmitting end for the output of the packet deformatter 809, and then outputs enhanced data.

[144] On the other hand, the data inputted to the enhanced decoder 804 may be any of main data or known data, or enhanced data. Here, the main data and known data do not undergo additional encoding but only Trellis encoding. Also, the enhanced data undergoes all the additional encoding and Trellis encoding.

[145] When the inputted data are main data or known data (or known data place holder), the enhanced decoder 804 performs Viterbi decoding for the inputted data or performs hard determination for soft determination value, and then outputs the result thereto. Also, the transmitting end regards RS parity byte and MPEG header byte, which are added to the enhanced data packet at the transmitting end, as main data, and does not perform additional encoding therefor. Therefore, Viterbi decoding is performed or hard determination is performed for soft determination value, such that the result can be outputted.

[146] On the other hand, when the inputted data is enhanced data, the enhanced decoder

804 performs soft determination decoding to obtain a soft determination value, and performs decoding for the soft determination value, such that decoding processes for the enhanced data can be completed. Here, the decoding for the soft determination value is a reverse operation of the enhanced encoder core at the transmitting end.

[147] Here, when the enhanced encoder core includes a 1/2 encoder and a block in- terleaver to perform a reverse operation thereof, the receiving end must include a block deinterleaver and a 1/2 decoder, as reversely arranged. In this situation, the block dein- terleaver performs deinterleaving for the received data and then the 1/2 decoder performs 1/2 decoding for the deinterleaving result. On the other hand, when the block interleaver was not used at the transmitting end, the receiving end does not need the block deinterleaver.

[148] Namely, the enhanced decoder 804 performs decoding for the enhanced data as a decoder whose structure is configured such that a Trellis decoder, a block deinterleaver (optional), and a 1/2 decoder are adjacently connected to each other.

[149] When the Trellis decoder and 1/2 decoder are configured as an enhanced decoder to output a soft determination value, the soft determination value of the Trellis decoder can assist determination of the 1/2 decoder. The 1/2 decoder receiving such assistance of the Trellis decoder can return its soft determination value to the Trellis decoder, such that it can assist determination of the Trellis decoder. Such decoding is referred to as turbo decoding. When the turbo decoding is adopted, the total decoding performance can be enhanced.

[150] There are algorithms to output the soft determination value, such as Soft Output

Viterbi Algorithm (SOVA), Suboptimum Soft output Algorithm (SSA), and Maximum A Posteriori (MAP), etc. Here, from the point of view of symbol errors, the MAP algorithm is superior to the SOVA algorithm. The MAP algorithm calculates probability in log domain while its performance does not decrease, and does not need estimation of noise distribution.

[151] As the transmitting method of the present invention is described above, when a block is used for initialization of a memory state of the Trellis encoding unit such that the memory of the Trellis encoding unit is returned from a predetermined state value to another the predetermined state value, the receiving end determines a soft determination value using algorithms, such as a MAP algorithm or a SOVA, etc., thereby obtaining optimal performance. [152] FIG. 12 illustrates a block diagram showing the structure of a digital broadcast transmitting system according to an embodiment of the present invention. The digital broadcast(or DTV) transmitting system includes a pre-processor 910, a packet multiplexer 921, a data randomizer 922, a Reed-Solomon (RS) encoder/non-systematic RS encoder 923, a data interleaver 924, a parity byte replacer 925, a non-systematic RS encoder 926, a frame multiplexer 928, and a transmitting system 930. The preprocessor 910 includes an enhanced data randomizer 911, a RS frame encoder 912, a block processor 913, a group formatter 914, a data deinterleaver 915, and a packet formatter 916.

[153] In the present invention having the above-described structure, main data are inputted to the packet multiplexer 921. Enhanced data are inputted to the enhanced data randomizer 911 of the pre-processor 910, wherein an additional coding process is performed so that the present invention can respond swiftly and appropriately against noise and change in channel. The enhanced data randomizer 911 randomizes the received enhanced data and outputs the randomized enhanced data to the RS frame encoder 912. At this point, by having the enhanced data randomizer 911 perform the randomizing process on the enhanced data, the randomizing process on the enhanced data by the data randomizer 922 in a later process may be omitted. Either the randomizer of the conventional broadcast system may be used as the randomizer for randomizing the enhanced data, or any other type of randomizer may be used herein.

[154] The RS frame encoder 912 receives the randomized enhanced data and performs at least one of an error correction coding process and an error detection coding process on the received data. Accordingly, by providing robustness to the enhanced data, the data can scatter group error that may occur due to a change in the frequency environment. Thus, the data can respond appropriately to the frequency environment which is very poor and liable to change. The RS frame multiplexer 912 also includes a process of mixing in row units many sets of enhanced data each having a pre-determined size. By performing an error correction coding process on the inputted enhanced data, the RS frame encoder 912 adds data required for the error correction and, then, performs an error detection coding process, thereby adding data required for the error detection process. The error correction coding uses the RS coding method, and the error detection coding uses the cyclic redundancy check (CRC) coding method. When performing the RS coding process, parity data required for the error correction are generated. And, when performing the CRC coding process, CRC data required for the error detection are generated.

[155] The RS frame encoder 912 performs CRC coding on the RS coded enhanced data in order to create the CRC code. The CRC code that is generated by the CRC coding process may be used to indicate whether the enhanced data have been damaged by an error while being transmitted through the channel. The present invention may adopt other types of error detection coding methods, apart from the CRC coding method, and may also use the error correction coding method so as to enhance the overall error correction ability of the receiving system. For example, assuming that the size of one RS frame is 187*N bytes, that (235,187)-RS coding process is performed on each column within the RS frame, and that a CRC coding process using a 2-byte (i.e., 16-bit) CRC checksum, then a RS frame having the size of 187*N bytes is expanded to a RS frame of 235*(N+2) bytes. The RS frame expanded by the RS frame encoder 912 is inputted to the block processor 913. The block processor 913 codes the RS-coded and CRC-coded enhanced data at a coding rate of G/H. Then, the block processor 913 outputs the G/H-rate coded enhanced data to the group formatter 914. In order to do so, the block processor 913 identifies the block data bytes being inputted from the RS frame encoder 912 as bits.

[156] The block processor 913 may receive supplemental information data such as signaling information, which include information on the system, and identifies the supplemental information data bytes as data bits. Herein, the supplemental information data, such as the signaling information, may equally pass through the enhanced data randomizer 911 and the RS frame encoder 912 so as to be inputted to the block processor 913. Alternatively, the supplemental information data may be directly inputted to the block processor 913 without passing through the enhanced data randomizer 911 and the RS frame encoder 912. The signaling information corresponds to information required for receiving and processing data included in the data group in the receiving system. Such signaling information includes data group information, multiplexing information, and burst information.

[157] As a G/H-rate encoder, the block processor 913 codes the inputted data at a coding rate of G/H and then outputs the G/H-rate coded data. For example, if 1 bit of the input data is coded to 2 bits and outputted, then G is equal to 1 and H is equal to 2 (i.e., G=I and H=2). Alternatively, if 1 bit of the input data is coded to 4 bits and outputted, then G is equal to 1 and H is equal to 4 (i.e., G=I and H=4). As an example of the present invention, it is assumed that the block processor 913 performs a coding process at a coding rate of 1/2 (also referred to as a 1/2-rate coding process) or a coding process at a coding rate of 1/4 (also referred to as a 1/4-rate coding process). More specifically, the block processor 913 codes the received enhanced data and supplemental information data, such as the signaling information, at either a coding rate of 1/2 or a coding rate of 1/4. Thereafter, the supplemental information data, such as the signaling information, are identified and processed as enhanced data.

[158] Since the 1/4-rate coding process has a higher coding rate than the 1/2-rate coding process, greater error correction ability may be provided. Therefore, in a later process, by allocating the 1/4-rate coded data in an area with deficient receiving performance within the group formatter 914, and by allocating the 1/2-rate coded data in an area with excellent receiving performance, the difference in the overall performance may be reduced. More specifically, in case of performing the 1/2-rate coding process, the block processor 913 receives 1 bit and codes the received 1 bit to 2 bits (i.e., 1 symbol). Then, the block processor 913 outputs the processed 2 bits (or 1 symbol). On the other hand, in case of performing the 1/4-rate coding process, the block processor 913 receives 1 bit and codes the received 1 bit to 4 bits (i.e., 2 symbols). Then, the block processor 913 outputs the processed 4 bits (or 2 symbols). Additionally, the block processor 913 performs a block interleaving process in symbol units on the symbol-coded data. Subsequently, the block processor 913 converts to bytes the data symbols that are block- interleaved and have the order rearranged.

[159] The group formatter 914 inserts the enhanced data outputted from the block processor 913 (herein, the enhanced data may include supplemental information data such as signaling information including transmission information) in a corresponding area within the data group, which is configured according to a pre-defined rule. Furthermore, in relation with the data deinterleaving process, various types of places h olders or known data are also inserted in corresponding areas within the data group. At this point, the data group may be described by at least one hierarchical area. Herein, the data allocated to the each area may vary depending upon the characteristic of each hierarchical area. Additionally, each group is configured to include a field synchronization signal.

[160] The present invention shows an example of the data group being divided into three hierarchical areas: a head area, a body area, and a tail area. Accordingly, in the data group that is inputted for the data deinterleaving process, data are first inputted to the head area, then inputted to the body area, and inputted finally to the tail area. In the example of the present invention, the head, body, and tail areas are configured so that the body area is not mixed with the main data area within the data group. Furthermore, in the present invention, the head, body, and tail areas may each be divided into lower hierarchical areas. For example, the head area may be divided into 3 lower hierarchical areas: a far head (FH) area, a middle head (MH) area, and a near head (NH) area. The body area may be divided into 4 lower hierarchical areas: a first lower body (Bl) area, a second lower body (B2) area, a third lower body (B3) area, and a fourth lower body (B4) area. And, finally, the tail area may be divided into 2 lower hierarchical areas: a far tail (FT) area and a near tail (NT) area.

[161] In the example of the present invention, the group formatter 914 inserts the enhanced data being outputted from the block processor 913 to the middle head (MH) area, the near head (NH) area, the first to fourth lower body (B 1 to B4) areas, and the near tail (NT) area. Herein, the type of enhanced data may vary depending upon the characteristic of each area. The data group is divided into a plurality of areas so that each area may be used for different purposes. More specifically, areas having less interference with the main data may show more enhanced receiving performance as compared with area having more interference with the main data. Additionally, when using the system in which the known data are inserted in the data group and then transmitted, and when a long set of consecutive known data is to be periodically (or regularly) inserted in the enhanced data, the body area is capable of regularly receiving such enhanced data having a predetermined length. However, since the enhanced data may be mixed with the main data in the head and tail areas, it is difficult to regularly insert the known data in these areas, and it is also difficult to insert long known data sets that are consecutive in these areas.

[162] Details such as the size of the data group, the number of hierarchical areas within the data group and the size of each hierarchical area, and the number of enhanced data bytes that may be inserted in each hierarchical area may vary depending upon the design of the system designer. Therefore, the above-described embodiment is merely an example that can facilitate the description of the present invention. In the group formatter 914, the data group may be configured to include a position (or place) in which the field synchronization signal is to be inserted. When assuming that the data group is divided into a plurality of hierarchical areas as described above, the block processor 913 may code the data that are to be inserted in each area at different coding rates.

[163] In the present invention, based upon the areas that are each expected to show different performance after the equalization process when using the channel information that may be used for the channel equalization process in the receiving system, a different coding rate may be applied to each of these areas. For example, the block processor 913 codes the enhanced data that are to be inserted in the near head (NH) area and the first to fourth lower body (Bl to B4) areas at a 1/2-coding rate. Thereafter, the group formatter 914 may insert the 1/2-rate coded enhanced data in the near head (NH) area and the first to fourth lower body (Bl to B4) areas. On the other hand, the block processor 913 codes the enhanced data that are to be inserted in the middle head (MH) area and the near tail (NT) area at a 1/4-coding rate, which has greater error correction ability than the 1/2-coding rate. Subsequently, the group formatter 914 may insert the 1/2-rate coded enhanced data in the middle head (MH) area and the near tail (NT) area. Furthermore, the block processor 913 codes the enhanced data that are to be inserted in the far head (FH) area and the far tail (FT) area at a coding rate having even greater error correction ability than the 1/4-coding rate. Thereafter, the group formatter 914 may inserts the coded enhanced data either in the far head (FH) and far tail (FT) areas or in a reserved area for future usage.

[164] Apart from the enhanced data, the group formatter 913 may also insert supplemental information data such as signaling information indicating the overall transmission information in the data group. Also, apart from the coded enhanced data outputted from the block processor 913, and in relation with the data deinterleaving process in a later process, the group formatter 914 may also insert a MPEG header place holder, a non-systematic RS parity place holder, and a main data place holder in the data group. Herein, the main data group place holder is inserted because the enhanced data and the main data may be mixed in the head and tail areas depending upon the input of the data deinterleaver. For example, based upon the output of the data after being deinterleaved, the place holder for the MPEG header may be allocated to the front of each data packet. Additionally, the group formatter 914 may either insert known data generated according to a pre-defined rule, or insert a known data place holder for inserting known data in a later process. Furthermore, a place holder for the initialization of the trellis encoder module 927 is inserted in a corresponding area. For example, the initialization data place holder may be inserted at the beginning (or front) of the data place sequence.

[165] The output of the group formatter 914 is inputted to the data deinterleaver 915.

And, the data deinterleaver 915 performs an inverse process of the data interleaver deinterleaving the data and place holder within the data group being outputted from the group formatter 914. Thereafter, the data deinterleaver 915 outputs the deinterelaved data to the packet formatter 916. Among the data deinterleaved and inputted, the packet formatter 916 removes the main data place holder and RS parity place holder that were allocated for the deinterleaving process from the inputted deinterleaved data. Thereafter, the remaining portion of the corresponding data is grouped, and 4 bytes of MPEG header are inserted therein. The 4-byte MPEG header is configured of a 1-byte MPEG synchronization byte added to the 3 -byte MPEG header place holder.

[166] When the group formatter 914 inserts the known data place holder, the packet formatter 916 may either insert actual known data in the known data place holder or output the known data place holder without any change or modification for a replacement insertion in a later process. Afterwards, the packet formatter 916 divides the data within the above-described packet-formatted data group into 188-byte unit enhanced data packets (i.e., MPEG TS packets), which are then provided to the packet multiplexer 921. The packet multiplexer 921 multiplexes the 188-byte unit enhanced data packet and main data packet outputted from the packet formatter 916 according to a pre-defined multiplexing method. Subsequently, the multiplexed data packets are outputted to the data randomizer 922. The multiplexing method may be modified or altered in accordance with diverse variables of the system design. [167] As an example of the multiplexing method of the packet multiplexer 921, the enhanced data burst section and the main data section may be identified along a time axis (or a chronological axis) and may be alternately repeated. At this point, the enhanced data burst section may transmit at least one data group, and the main data section may transmit only the main data. The enhanced data burst section may also transmit the main data. If the enhanced data are outputted in a burst structure, as described above, the receiving system receiving only the enhanced data may turn the power on only during the burst section so as to receive the enhanced data, and may turn the power off during the main data section in which main data are transmitted, so as to prevent the main data from being received, thereby reducing the power consumption of the receiving system.

[168] When the data being inputted correspond to the main data packet, the data randomizer 922 performs the same randomizing process of the conventional randomizer. More specifically, the MPEG synchronization byte included in the main data packet is discarded and a pseudo random byte generated from the remaining 187 bytes is used so as to randomize the data. Thereafter, the randomized data are outputted to the RS encoder/non-systematic RS encoder 923. However, when the inputted data correspond to the enhanced data packet, the MPEG synchronization byte of the 4-byte MPEG header included in the enhanced data packet is discarded, and data randomizing is performed only on the remaining 3 -byte MPEG header. Randomizing is not performed on the remaining portion of the enhanced data. Instead, the remaining portion of the enhanced data is outputted to the RS encoder/non-systematic RS encoder 923. This is because the randomizing process has already been performed on the enhanced data by the enhanced data randomizer 911 in an earlier process. Herein, a data randomizing process may or may not be performed on the known data (or known data place holder) and the initialization data place holder included in the enhanced data packet.

[169] The RS encoder/non-systematic RS encoder 923 RS-codes the data randomized by the data randomizer 922 or the data bypassing the data randomizer 922. Then, the RS encoder/non-systematic RS encoder 923 adds a 20-byte RS parity to the coded data, thereby outputting the RS-parity-added data to the data interleaver 924. At this point, if the inputted data correspond to the main data packet, the RS encoder/non-systematic RS encoder 923 performs a systematic RS-coding process identical to that of the conventional receiving system on the inputted data, thereby adding the 20-byte RS parity at the end of the 187-byte data. Alternatively, if the inputted data correspond to the enhanced data packet, the 20 bytes of RS parity gained by performing the non- systematic RS-coding are respectively inserted in the decided parity byte places within the enhanced data packet. Herein, the data interleaver 924 corresponds to a byte unit convolutional interleaver. The output of the data interleaver 924 is inputted to the parity byte replacer 925 and the non-systematic RS encoder 926.

[170] Meanwhile, a memory within the trellis encoding module 927, which is positioned after the parity byte replacer 925, should first be initialized in order to allow the output data of the trellis encoding module 927 so as to become the known data defined based upon an agreement between the receiving system and the transmitting system. More specifically, the memory of the trellis encoding module 927 should first be initialized before the known data sequence being inputted is trellis -encoded. At this point, the beginning of the known data sequence that is inputted corresponds to the initialization data place holder inserted by the group formatter 914 and not the actual known data. Therefore, a process of generating initialization data right before the trellis -encoding of the known data sequence being inputted and a process of replacing the initialization data place holder of the corresponding trellis encoding module memory with the newly generated initialization data are required.

[171] A value of the trellis memory initialization data is decided based upon the memory status of the trellis encoding module 927, thereby generating the trellis memory initialization data accordingly. Due to the influence of the replace initialization data, a process of recalculating the RS parity, thereby replacing the RS parity outputted from the trellis encoding module 927 with the newly calculated RS parity is required. Accordingly, the non-systematic RS encoder 926 receives the enhanced data packet including the initialization data place holder that is to be replaced with the initialization data from the data interleaver 924 and also receives the initialization data from the trellis encoding module 927. Thereafter, among the received enhanced data packet, the initialization data place holder is replaced with the initialization data. Subsequently, the RS parity data added to the enhanced data packet are removed. Then, a new non- systematic RS parity is calculated and outputted to the parity byte replacer 925. Accordingly, the parity byte replacer 925 selects the output of the data interleaver 924 as the data within the enhanced data packet, and selects the output of the non-systematic RS encoder 926 as the RS parity. Thereafter, the parity byte replacer 925 outputs the selected data.

[172] Meanwhile, if the main data packet is inputted, or if the enhanced data packet that does not include the initialization data place holder that is to be replaced, the parity byte replacer 925 selects the data and RS parity outputted from the data interleaver 924 and directly outputs the selected data to the trellis encoding module 927 without modification. The trellis encoding module 927 converts the byte -unit data to symbol-unit data and 12- way interleaves and trellis -encodes the converted data, which are then outputted to the frame multiplexer 928. The frame multiplexer 928 inserts field synchronization and segment synchronization signals in the output of the trellis encoding module 927 and then outputs the processed data to the transmitter 930. Herein, the transmitter 930 includes a pilot inserter 931, a modulator 932, and a radio frequency (RF) up-converter 933. The operation of the transmitter 930 is identical to the conventional transmitters. Therefore, a detailed description of the same will be omitted for simplicity.

[173] FIG. 13 illustrates a block diagram of a demodulating unit included in the receiving system according to another embodiment of the present invention. Herein, the demodulating unit may effectively process signals transmitted from the transmitting system shown in FIG. 12. Referring to FIG. 13, the demodulating unit includes a demodulator 1001, a channel equalizer 1002, a known data detector 1003, a block decoder 1004, an enhanced data deformatter 1005, a RS frame decoder 1006, an enhanced data derandomizer 1007, a data deinterleaver 1008, a RS decoder 1009, and a main data derandomizer 1010. For simplicity, the demodulator 1001, the channel equalizer 1002, the known data detector 1003, the block decoder 1004, the enhanced data deformatter 1005, the RS frame decoder 1006, and the enhanced data de- randomizer 1007 will be referred to as an enhanced data processor. And, the data deinterleaver 1008, the RS decoder 1009, and the main data derandomizer 1010 will be referred to as a main data processor.

[174] More specifically, the enhanced data including known data and the main data are received through the tuner and inputted to the demodulator 1001 and the known data detector 1003. The demodulator 1001 performs automatic gain control, carrier wave recovery, and timing recovery on the data that are being inputted, thereby creating baseband data, which are then outputted to the equalizer 1002 and the known data detector 1003. The equalizer 1002 compensates the distortion within the channel included in the demodulated data. Then, the equalizer 1002 outputs the compensated data to the block decoder 1004.

[175] At this point, the known data detector 1003 detects the known data place inserted by the transmitting system to the input/output data of the demodulator 1001 (i.e., data prior to demodulation or data after demodulation). Then, along with the position information, the known data detector 1003 outputs the symbol sequence of the known data generated from the corresponding position to the demodulator 1001 and the equalizer 1002. Additionally, the known data detector 1003 outputs information enabling the block decoder 1004 to identify the enhanced data being additionally e ncoded by the transmitting system and the main data that are not additionally encoded to the block decoder 1004. Furthermore, although the connection is not shown in FIG. 13, the information detected by the known data detector 1003 may be used in the overall receiving system and may also be used in the enhanced data formatter 1005 and the RS frame decoder 1006. [176] By using the known data symbol sequence when performing the timing recovery or carrier wave recovery, the demodulating performance of the demodulator 1001 may be enhanced. Similarly, by using the known data, the channel equalizing performance of the channel equalizer 1002 may be enhanced. Furthermore, by feeding-back the demodulation result of the block demodulator 1004, the channel equalizing performance may also be enhanced. Herein, the channel equalizer 1002 may perform channel equalization through various methods. In the present invention, a method of estimating a channel impulse response (CIR) for performing the channel equalization process will be given as an example of the present invention. More specifically, in the present invention, the channel impulse response (CIR) is differently estimated and applied in accordance with each hierarchical area within the data group that are transmitted from the transmitting system. Furthermore, by using the known data having the position (or place) and contents pre-known according to an agreement between the transmitting system and the receiving system, so as to estimate the CIR, the channel equalization process may be processed with more stability.

[177] In the present invention, one data group that is inputted for channel equalization is divided into three hierarchical areas: a head area, a body area, and a tail area. Then, each of the areas is divided into lower hierarchical areas. More specifically, the head area may be divided into a far head (FH) area, a middle head (MH) area, and a near head (NH) area. And, the tail area may be divided into a far tail (FT) area and a near tail (NT) area. Furthermore, based upon a long known data sequence, the body area may be divided into 4 lower hierarchical areas: a first lower body (Bl) area, a second lower body (B2) area, a third lower body (B3) area, and a fourth lower body (B4) area. In performing channel equalization on the data within the data group by using the CIR estimated from the field synchronization signal and the known data sequence, and in accordance with the characteristic of each area, either one of the estimated CIRs may be directly used without modification, or a CIR created by interpolating or extrapolating a plurality of CIRs may be used.

[178] Meanwhile, if the data being channel equalized and then inputted to the block decoder 1004 correspond to the enhanced data on which additional encoding and trellis encoding are both performed by the transmitting system, trellis-decoding and additional decoding processes are performed as inverse processes of the transmitting system. Alternatively, if the data being channel equalized and then inputted to the block decoder 1004 correspond to the main data on which additional encoding is not performed and only trellis-encoding is performed by the transmitting system, only the trellis-decoding process is performed. The data group decoded by the block decoder 1004 is inputted to the enhanced data deformatter 1005, and the main data packet is inputted to the data deinterleaver 1008. [179] More specifically, if the inputted data correspond to the main data, the block decoder 1004 performs Viterbi decoding on the inputted data, so as to either output a hard decision value or hard-decide a soft decision value and output the hard-decided result. On the other hand, if the inputted correspond to the enhanced data, the block decoder 1004 outputs either a hard decision value or a soft decision value on the inputted enhanced data. In other words, if the data inputted to the block decoder 1004 correspond to the enhanced data, the block decoder 1004 performs a decoding process on the data encoded by the block processor and the trellis encoder of the transmitting system. At this point, the output of the RS frame encoder included in the pre-processor of the transmitting system becomes an external code, and the output of the block processor and the trellis encoder becomes an internal code. In order to show maximum performance of the external code when decoding such connection codes, the decoder of the internal code should output a soft decision value. Therefore, the block decoder 1004 may output a hard decision value on the enhanced data. However, when required, it is more preferable that the block decoder 1004 outputs a soft decision value.

[180] The present invention may also be used for configuring a reliability map using the soft decision value. The reliability map determines and indicates whether a byte corresponding to a group of 8 bits decided by the code of the soft decision value is reliable. For example, when an absolute value of the soft decision value exceeds a predetermined threshold value, the value of the bit corresponding to the soft decision value code is determined to be reliable. However, if the absolute value does not exceed the pre-determined threshold value, then the value of the corresponding bit is determined to be not reliable. Further, if at least one bit among the group of 8 bits, which are determined based upon the soft decision value, is determined to be not reliable, then the reliability map indicates that the entire byte is not reliable. Herein, the process of determining the reliability by 1-bit units is merely exemplary. The corresponding byte may also be indicated to be not reliable if a plurality of bits (e.g., 4 bits) is determined to be not reliable.

[181] Conversely, when all of the bits are determined to be reliable within one byte (i.e., when the absolute value of the soft value of all bits exceeds the pre-determined threshold value), then the reliability map determines and indicates that the corresponding data byte is reliable. Similarly, when more than 4 bits are determined to be reliable within one data byte, then the reliability map determines and indicates that the corresponding data byte is reliable. The estimated numbers are merely exemplary and do not limit the scope and spirit of the present invention. Herein, the reliability map may be used when performing error correction decoding processes.

[182] Meanwhile, the data deinterleaver 1008, the RS decoder 1009, and the main data derandomizer 1010 are blocks required for receiving the main data. These blocks may not be required in a receiving system structure that receives only the enhanced data. The data deinterleaver 1008 performs an inverse process of the data interleaver of the transmitting system. More specifically, the data deinterleaver 1008 deinterleaves the main data being outputted from the block decode 1004 and outputs the deinterleaved data to the RS decoder 1009. The RS decoder 1009 performs systematic RS decoding on the deinterleaved data and outputs the systematically decoded data to the main data derandomizer 1010. The main data derandomizer 1010 receives the data outputted from the RS decoder 1009 so as to generate the same pseudo random byte as that of the randomizer in the transmitting system. The main data derandomizer 1010 then performs a bitwise exclusive OR (XOR) operation on the generated pseudo random data byte, thereby inserting the MPEG synchronization bytes to the beginning of each packet so as to output the data in 188-byte main data packet units.

[183] Herein, the format of the data being outputted to the enhanced data deformatter

1005 from the block decoder 1004 is a data group format. At this point, the enhanced data deformatter 1005 already knows the structure of the input data. Therefore, the enhanced data deformatter 1005 identifies the system information including signaling information and the enhanced data from the data group. Thereafter, the identified signaling information is transmitted to where the system information is required, and the enhanced data are outputted to the RS frame decoder 1006. The enhanced data de- formatter 1005 removes the known data, trellis initialization data, and MPEG header that were included in the main data and the data group and also removes the RS parity that was added by the RS encoder/non-systematic RS encoder of the transmitting system. Thereafter, the processed data are outputted to the RS frame decoder 1006.

[184] More specifically, the RS frame decoder 1006 receives the RS-coded and CRC- coded enhanced data from the enhanced data deformatter 1005 so as to configure the RS frame. The RS frame decoder 1006 performs an inverse process of the RS frame encoder included in the transmitting system, thereby correcting the errors within the RS frame. Then, the 1-byte MPEG synchronization byte, which was removed during the RS frame coding process, is added to the error corrected enhanced data packet. Subsequently, the processed data are outputted to the enhanced data derandomizer 1007. Herein, the enhanced data derandomizer 1007 performs a derandomizing process, which corresponds to an inverse process of the enhanced data randomizer included in the transmitting system, on the received enhanced data. Then, by outputting the processed data, the enhanced data transmitted from the transmitting system can be obtained.

[185] According to an embodiment of the present invention, the RS frame decoder 1006 may also be configured as follows. The RS frame decoder 1006 may perform a CRC syndrome check on the RS frame, thereby verifying whether or not an error has occurred in each row. Subsequently, the CRC checksum is removed and the presence of an error is indicated on a CRC error flag corresponding to each row. Then, a RS decoding process is performed on the RS frame having the CRC checksum removed in a column direction. At this point, depending upon the number of CRC error flags, a RS erasure decoding process may be performed. More specifically, by checking the CRC error flags corresponding to each row within the RS frame, the number of CRC error flags may be determined whether it is greater or smaller than the maximum number of errors, when RS decoding the number of rows with errors (or erroneous rows) in the column direction. Herein, the maximum number of errors corresponds to the number of parity bytes inserted during the RS decoding process. As an example of the present invention, it is assumed that 48 parity bytes are added to each column.

[186] If the number of rows with CRC errors is equal to or smaller than the maximum number of errors (e.g., 48), which may be corrected by the RS erasure decoding process, the RS erasure decoding process is performed on the RS frame in the column direction. Thereafter, the 48 bytes of parity data that were added at the end of each column are removed. However, if the number of rows with CRC errors is greater than the maximum number of errors (e.g., 48), which may be corrected by the RS erasure decoding process, the RS erasure decoding process cannot be performed. In this case, the error may be corrected by performing a general RS decoding process.

[187] As another embodiment of the present invention, the error correction ability may be enhanced by using the reliability map created when configuring the RS frame from the soft decision value. More specifically, the RS frame decoder 1006 compares the absolute value of the soft decision value obtained from the block decoder 1004 to the pre-determined threshold value so as to determine the reliability of the bit values that are decided by the code of the corresponding soft decision value. Then, 8 bits are grouped to configure a byte. Then, the reliability information of the corresponding byte is indicated on the reliability map. Therefore, even if a specific row is determined to have CRC errors as a result of the CRC syndrome checking process of the corresponding row, it is not assumed that all of the data bytes included in the corresponding row have error. Instead, only the data bytes that are determined to be not reliable, after referring to the reliability information on the reliability map, are set to have errors. In other words, regardless of the presence of CRC errors in the corresponding row, only the data bytes that are determined to be not reliable (or unreliable) by the reliability map are set as erasure points.

[188] Thereafter, if the number of erasure points for each column is equal to or smaller than the maximum number of errors (e.g., 48), the RS erasure decoding process is performed on the corresponding the column. Conversely, if the number of erasure points is greater than the maximum number of errors (e.g., 48), which may be corrected by the RS erasure decoding process, a general decoding process is performed on the corresponding column. In other words, if the number of rows having CRC errors is greater than the maximum number of errors (e.g., 48), which may be corrected by the RS erasure decoding process, either a RS erasure decoding process or a general RS decoding process is performed on a particular column in accordance with the number of erasure point within the corresponding column, wherein the number is decided based upon the reliability information on the reliability map. When the above- described process is performed, the error correction decoding process is performed in the direction of all of the columns included in the RS frame. Thereafter, the 48 bytes of parity data added to the end of each column are removed.

[189] FIG. 14 illustrates a block diagram showing the structure of a digital broadcast receiving system according to an embodiment of the present invention. Referring to FIG. 14, the digital broadcast receiving system includes a tuner 2001, a demodulating unit 2002, a demultiplexer 2003, an audio decoder 2004, a video decoder 2005, a native TV application manager 2006, a channel manager 2007, a channel map 2008, a first memory 2009, a data decoder 2010, a second memory 2011, a system manager 2012, a data broadcasting application manager 2013, a storage controller 2014, and a third memory 2015. Herein, the third memory 2015 is a mass storage device, such as a hard disk drive (HDD) or a memory chip. The tuner 2001 tunes a frequency of a specific channel through any one of an antenna, cable, and satellite. Then, the tuner 2001 down-converts the tuned frequency to an intermediate frequency (IF), which is then outputted to the demodulating unit 2002. At this point, the tuner 2001 is controlled by the channel manager 2007. Additionally, the result and strength of the broadcast signal of the tuned channel are also reported to the channel manager 2007. The data that are being received by the frequency of the tuned specific channel include main data, enhanced data, and table data for decoding the main data and enhanced data.

[190] In the embodiment of the present invention, examples of the enhanced data may include data provided for data service, such as Java application data, HTML application data, XML data, and so on. The data provided for such data services may correspond either to a Java class file for the Java application, or to a directory file designating positions (or locations) of such files. Furthermore, such data may also correspond to an audio file and/or a video file used in each application. The data services may include weather forecast services, traffic information services, stock information services, services providing information quiz programs providing audience participation services, real time poll, user interactive education programs, gaming services, services providing information on soap opera (or TV series) synopsis, characters, original sound track, filing sites, services providing information on past sports matches, profiles and accomplishments of sports players, product information and product ordering services, services providing information on broadcast programs by media type, airing time, subject, and so on. The types of data services described above are only exemplary and are not limited only to the examples given herein. Furthermore, depending upon the embodiment of the present invention, the enhanced data may correspond to meta data. For example, the meta data use the XML application so as to be transmitted through a DSM-CC protocol.

[191] The demodulating unit 2002 performs demodulation and channel equalization on the signal being outputted from the tuner 2001, thereby identifying the main data and the enhanced data. Thereafter, the identified main data and enhanced data are outputted in TS packet units. Examples of the demodulating unit 2002 is shown in FIG. 11 and FIG. 13. The demodulating unit shown in FIG. 11 and FIG. 13 is merely exemplary and the scope of the present invention is not limited to the examples set forth herein. In the embodiment given as an example of the present invention, only the enhanced data packet outputted from the demodulating unit 2002 is inputted to the demultiplexer 2003. In this case, the main data packet is inputted to another demultiplexer (not shown) that processes main data packets. Herein, the storage controller 2014 is also connected to the other demultiplexer in order to store the main data after processing the main data packets. The demultiplexer of the present invention may also be designed to process both enhanced data packets and main data packets in a single demultiplexer.

[192] The storage controller 2014 is interfaced with the demultipelxer so as to control instant recording, reserved (or pre-programmed) recording, time shift, and so on of the enhanced data and/or main data. For example, when one of instant recording, reserved (or pre-programmed) recording, and time shift is set and programmed in the receiving system (or receiver) shown in FIG. 14, the corresponding enhanced data and/or main data that are inputted to the demultiplexer are stored in the third memory 2015 in accordance with the control of the storage controller 2014. The third memory 2015 may be described as a temporary storage area and/or a permanent storage area. Herein, the temporary storage area is used for the time shifting function, and the permanent storage area is used for a permanent storage of data according to the user's choice (or decision).

[193] When the data stored in the third memory 2015 need to be reproduced (or played), the storage controller 2014 reads the corresponding data stored in the third memory 2015 and outputs the read data to the corresponding demultiplexer (e.g., the enhanced data are outputted to the demultiplexer 2003 shown in FIG. 14). At this point, according to the embodiment of the present invention, since the storage capacity of the third memory 2015 is limited, the compression encoded enhanced data and/or main data that are being inputted are directly stored in the third memory 2015 without any modification for the efficiency of the storage capacity. In this case, depending upon the reproduction (or reading) command, the data read from the third memory 2015 pass trough the demultiplexer so as to be inputted to the corresponding decoder, thereby being restored to the initial state.

[194] The storage controller 2014 may control the reproduction (or play), fast-forward, rewind, slow motion, instant replay functions of the data that are already stored in the third memory 2015 or presently being buffered. Herein, the instant replay function corresponds to repeatedly viewing scenes that the viewer (or user) wishes to view once again. The instant replay function may be performed on stored data and also on data that are currently being received in real time by associating the instant replay function with the time shift function. If the data being inputted correspond to the analog format, for example, if the transmission mode is NTSC, PAL, and so on, the storage controller 2014 compression encodes the inputted data and stored the compression-encoded data to the third memory 2015. In order to do so, the storage controller 2014 may include an encoder, wherein the encoder may be embodied as one of software, middleware, and hardware. Herein, an MPEG encoder may be used as the encoder according to an embodiment of the present invention. The encoder may also be provided outside of the storage controller 2014.

[195] Meanwhile, in order to prevent illegal duplication (or copies) of the input data being stored in the third memory 2015, the storage controller 2014 scrambles the input data and stores the scrambled data in the third memory 2015. Accordingly, the storage controller 2014 may include a scramble algorithm for scrambling the data stored in the third memory 2015 and a descramble algorithm for descrambling the data read from the third memory 2015. Herein, the definition of scramble includes encryption, and the definition of descramble includes decryption. The scramble method may include using an arbitrary key (e.g., control word) to modify a desired set of data, and also a method of mixing signals.

[196] Meanwhile, the demultiplexer 2003 receives the real-time data outputted from the demodulating unit 2002 or the data read from the third memory 2015 and demultiplexes the received data. In the example given in the present invention, the demultiplexer 2003 performs demultiplexing on the enhanced data packet. Therefore, in the present invention, the receiving and processing of the enhanced data will be described in detail. It should also be noted that a detailed description of the processing of the main data will be omitted for simplicity starting from the description of the demultiplexer 2003 and the subsequent elements.

[197] The demultiplexer 2003 demultiplexes enhanced data and program specific information/program and system information protocol (PSI/PSIP) tables from the enhanced data packet inputted in accordance with the control of the data decoder 2010. Thereafter, the demultiplexed enhanced data and PSFPSIP tables are outputted to the data decoder 2010 in a section format. In order to extract the enhanced data from the channel through which enhanced data are transmitted and to decode the extracted enhanced data, system information is required. Such system information may also be referred to as service information. The system information may include channel information, event information, etc. In the embodiment of the present invention, the PSI/ PSIP tables are applied as the system information. However, the present invention is not limited to the example set forth herein. More specifically, regardless of the name, any protocol transmitting system information in a table format may be applied in the present invention.

[198] The PSI table is an MPEG-2 system standard defined for identifying the channels and the programs. The PSIP table is an advanced television systems committee (ATSC) standard that can identify the channels and the programs. The PSI table may include a program association table (PAT), a conditional access table (CAT), a program map table (PMT), and a network information table (NIT). Herein, the PAT corresponds to special information that is transmitted by a data packet having a PID of ¹O'. The PAT transmits PID information of the PMT and PID information of the NIT corresponding to each program. The CAT transmits information on a paid broadcast system used by the transmitting system. The PMT transmits PID information of a transport stream (TS) packet, in which program identification numbers and individual bit sequences of video and audio data configuring the corresponding program are transmitted, and the PID information, in which PCR is transmitted. The NIT transmits information of the actual transmission network.

[199] The PSIP table may include a virtual channel table (VCT), a system time table

(STT), a rating region table (RRT), an extended text table (ETT), a direct channel change table (DCCT), an event information table (EIT), and a master guide table (MGT). The VCT transmits information on virtual channels, such as channel information for selecting channels and information such as packet identification (PID) numbers for receiving the audio and/or video data. More specifically, when the VCT is parsed, the PID of the audio/video data of the broadcast program may be known. Herein, the corresponding audio/video data are transmitted within the channel along with the channel name and the channel number. The STT transmits information on the current data and timing information. The RRT transmits information on region and consultation organs for program ratings. The ETT transmits additional description of a specific channel and broadcast program. The EIT transmits information on virtual channel events (e.g., program title, program start time, etc.). The DCCT/DCCSCT transmits information associated with automatic (or direct) channel change. And, the MGT transmits the versions and PID information of the above-mentioned tables included in the PSIP.

[200] Each of the above-described tables included in the PSI/PSIP is configured of a basic unit referred to as a "section" and a combination of one or more sections forms a table. For example, the VCT may be divided into 256 sections. Herein, one section may include a plurality of virtual channel information. However, a single set of virtual channel information is not divided into two or more sections. At this point, the receiving system may parse and decode the data for the data service that are transmitting by using only the tables included in the PSI, or only the tables included in the PISP, or a combination of tables included in both the PSI and the PSIP. In order to parse and decode the data for the data service, at least one of the PAT and PMT included in the PSI, and the VCT included in the PSIP is required. For example, the PAT may include the system information for transmitting the data corresponding to the data service, and the PID of the PMT corresponding to the data service data (or program number). The PMT may include the PID of the TS packet used for transmitting the data service data. The VCT may include information on the virtual channel for transmitting the data service data, and the PID of the TS packet for transmitting the data service data.

[201] Meanwhile, depending upon the embodiment of the present invention, a DVB-SI may be applied instead of the PSIP. The DVB-SI may include a network information table (NIT), a service description table (SDT), an event information table (EIT), and a time and data table (TDT). The DVB-SI may be used in combination with the above- described PSI. Herein, the NIT divides the services corresponding to particular network providers by specific groups. The NIT includes all tuning information that are used during the IRD set-up. The NIT may be used for informing or notifying any change in the tuning information. The SDT includes the service name and different parameters associated with each service corresponding to a particular MPEG multiplex. The EIT is used for transmitting information associated with all events occurring in the MPEG multiplex. The EIT includes information on the current transmission and also includes information selectively containing different transmission streams that may be received by the IRD. And, the TDT is used for updating the clock included in the IRD.

[202] Furthermore, three selective SI tables (i.e., a bouquet associate table (BAT), a running status table (RST), and a stuffing table (ST)) may also be included. More specifically, the bouquet associate table (BAT) provides a service grouping method enabling the IRD to provide services to the viewers. Each specific service may belong to at least one 'bouquet' unit. A running status table (RST) section is used for promptly and instantly updating at least one event execution status. The execution status section is transmitted only once at the changing point of the event status. Other SI tables are generally transmitted several times. The stuffing table (ST) may be used for replacing or discarding a subsidiary table or the entire SI tables.

[203] In the present invention, the enhanced data included in the payload within the TS packet consist of a digital storage media-command and control (DSM-CC) section format. However, the TS packet including the data service data may correspond either to a packetized elementary stream (PES) type or to a section type. More specifically, either the PES type data service data configure the TS packet, or the section type data service data configure the TS packet. The TS packet configured of the section type data will be given as the example of the present invention. At this point, the data service data are includes in the digital storage media-command and control (DSM-CC) section. Herein, the DSM-CC section is then configured of a 188-byte unit TS packet.

[204] Furthermore, the packet identification of the TS packet configuring the DSM-CC section is included in a data service table (DST). When transmitting the DST, '0x95' is assigned as the value of a streamjype field included in the service location descriptor of the PMT or the VCT. More specifically, when the PMT or VCT stream_type field value is '0x95', the receiving system may acknowledge that data broadcasting including enhanced data (i.e., the enhanced data) is being received. At this point, the enhanced data may be transmitted by a data carousel method. The data carousel method corresponds to repeatedly transmitting identical data on a regular basis.

[205] At this point, according to the control of the data decoder 2010, the demultiplexer

2003 performs section filtering, thereby discarding repetitive sections and outputting only the non-repetitive sections to the data decoder 2010. The demultiplexer 2003 may also output only the sections configuring desired tables (e.g., VCT) to the data decoder 2010 by section filtering. Herein, the VCT may include a specific descriptor for the enhanced data. However, the present invention does not exclude the possibilities of the enhanced data being included in other tables, such as the PMT. The section filtering method may include a method of verifying the PID of a table defined by the MGT, such as the VCT, prior to performing the section filtering process. Alternatively, the section filtering method may also include a method of directly performing the section filtering process without verifying the MGT, when the VCT includes a fixed PID (i.e., a base PID). At this point, the demultiplexer 2003 performs the section filtering process by referring to a table_id field, a version_number field, a section_number field, etc.

[206] As described above, the method of defining the PID of the VCT broadly includes two different methods. Herein, the PID of the VCT is a packet identifier required for identifying the VCT from other tables. The first method consists of setting the PID of the VCT so that it is dependent to the MGT. In this case, the receiving system cannot directly verify the VCT among the many PSI and/or PSIP tables. Instead, the receiving system must check the PID defined in the MGT in order to read the VCT. Herein, the MGT defines the PID, size, version number, and so on, of diverse tables. The second method consists of setting the PID of the VCT so that the PID is given a base PID value (or a fixed PID value), thereby being independent from the MGT. In this case, unlike in the first method, the VCT according to the present invention may be identified without having to verify every single PID included in the MGT. Evidently, an agreement on the base PID must be previously made between the transmitting system and the receiving system.

[207] Meanwhile, in the embodiment of the present invention, the demultiplexer 2003 may output only an application information table (AIT) to the data decoder 2010 by section filtering. The AIT includes information on an application being operated in the receiving system for the data service. The AIT may also be referred to as an XAIT, and an AMT. Therefore, any table including application information may correspond to the following description. When the AIT is transmitted, a value of '0x05' may be assigned to a streamjype field of the PMT. The AIT may include application information, such as application name, application version, application priority, application ID, application status (i.e., auto-start, user-specific settings, kill, etc.), application type (i.e., Java or HTML), position (or location) of stream including application class and data files, application platform directory, and location of application icon.

[208] In the method for detecting application information for the data service by using the

AIT, component_tag, original_network_id, transport_stream_id, and service_id fields may be used for detecting the application information. The component_tag field designates an elementary stream carrying a DSI of a corresponding object carousel. The original_network_id field indicates a DVB-SI original_network_id of the TS providing transport connection. The transport_stream_id field indicates the MPEG TS of the TS providing transport connection, and the service_id field indicates the DVB- SI of the service providing transport connection. Information on a specific channel may be obtained by using the original_network_id field, the transport_stream_id field, and the service_id field. The data service data, such as the application data, detected by using the above-described method may be stored in the second memory 2011 by the data decoder 2010.

[209] The data decoder 2010 parses the DSM-CC section configuring the demultiplexed enhanced data. Then, the enhanced data corresponding to the parsed result are stored as a database in the second memory 2011. The data decoder 2010 groups a plurality of sections having the same table identification (table_id) so as to configure a table, which is then parsed. Thereafter, the parsed result is stored as a database in the second memory 2011. At this point, by parsing data and/or sections, the data decoder 2010 reads all of the remaining actual section data that are not section-filtered by the de- multiplexer 2003. Then, the data decoder 2010 stores the read data to the second memory 2011. The second memory 2011 corresponds to a table and data carousel database storing system information parsed from tables and enhanced data parsed from the DSM-CC section. Herein, a table_id field, a section_number field, and a last_section_number field included in the table may be used to indicate whether the corresponding table is configured of a single section or a plurality of sections. For example, TS packets having the PID of the VCT are grouped to form a section, and sections having table identifiers allocated to the VCT are grouped to form the VCT.

[210] When the VCT is parsed, information on the virtual channel to which enhanced data are transmitted may be obtained. The obtained application identification information, service component identification information, and service information corresponding to the data service may either be stored in the second memory 2011 or be outputted to the data broadcasting application manager 2013. In addition, reference may be made to the application identification information, service component identification information, and service information in order to decode the data service data. Alternatively, such information may also prepare the operation of the application program for the data service. Furthermore, the data decoder 2010 controls the demultiplexing of the system information table, which corresponds to the information table associated with the channel and events. Thereafter, an A.V PID list may be transmitted to the channel manager 2007.

[211] The channel manager 2007 may refer to the channel map 2008 in order to transmit a request for receiving system-related information data to the data decoder 2010, thereby receiving the corresponding result. In addition, the channel manager 2007 may also control the channel tuning of the tuner 2001. Furthermore, the channel manager 2007 may directly control the demultiplexer 2003, so as to set up the A/V PID, thereby controlling the audio decoder 2004 and the video decoder 2005. The audio decoder 2004 and the video decoder 2005 may respectively decode and output the audio data and video data demultiplexed from the main data packet. Alternatively, the audio decoder 2004 and the video decoder 2005 may respectively decode and output the audio data and video data demultiplexed from the enhanced data packet. Meanwhile, when the enhanced data include data service data, and also audio data and video data, it is apparent that the audio data and video data demultiplexed by the demultiplexer 2003 are respectively decoded by the audio decoder 2004 and the video decoder 2005. For example, an audio-coding (AC)-3 decoding algorithm may be applied to the audio decoder 2004, and a MPEG-2 decoding algorithm may be applied to the video decoder 2005.

[212] Meanwhile, the native TV application manager 2006 operates a native application program stored in the first memory 2009, thereby performing general functions such as channel change. The native application program refers to software stored in the receiving system upon shipping of the product. More specifically, when a user request (or command) is transmitted to the receiving system through a user interface (UI), the native TV application manger 2006 displays the user request on a screen through a graphic user interface (GUI), thereby responding to the user's request. The user interface receives the user request through an input device, such as a remote controller, a key pad, a jog controller, an a touch-screen provided on the screen, and then outputs the received user request to the native TV application manager 2006 and the data broadcasting application manager 2013. Furthermore, the native TV application manager 2006 controls the channel manager 2007, thereby controlling channel- associated, such as the management of the channel map 2008, and controlling the data decoder 2010. The native TV application manager 2006 also controls the GUI of the overall receiving system, thereby storing the user request and status of the receiving system in the first memory 2009 and restoring the stored information.

[213] The channel manager 2007 controls the tuner 2001 and the data decoder 2010, so as to managing the channel map 2008 so that it can respond to the channel request made by the user. More specifically, channel manager 2007 sends a request to the data decoder 2010 so that the tables associated with the channels that are to be tuned are parsed. The results of the parsed tables are reported to the channel manager 2007 by the data decoder 2010. Thereafter, based on the parsed results, the channel manager 2007 updates the channel map 2008 and sets up a PID in the demultiplexer 2003 for demultiplexing the tables associated with the data service data from the enhanced data.

[214] The system manager 2012 controls the booting of the receiving system by turning the power on or off. Then, the system manager 2012 stores ROM images (including downloaded software images) in the first memory 2009. More specifically, the first memory 2009 stores management programs such as operating system (OS) programs required for managing the receiving system and also application program executing data service functions. The application program is a program processing the data service data stored in the second memory 2011 so as to provide the user with the data service. If the data service data are stored in the second memory 2011, the corresponding data service data are processed by the above-described application program or by other application programs, thereby being provided to the user. The management program and application program stored in the first memory 2009 may be updated or corrected to a newly downloaded program. Furthermore, the storage of the stored management program and application program is maintained without being deleted even if the power of the system is shut down. Therefore, when the power is supplied the programs may be executed without having to be newly downloaded once again.

[215] The application program for providing data service according to the present invention may either be initially stored in the first memory 2009 upon the shipping of the receiving system, or be stored in the first 2009 after being downloaded. The application program for the data service (i.e., the data service providing application program) stored in the first memory 2009 may also be deleted, updated, and corrected. Furthermore, the data service providing application program may be downloaded and executed along with the data service data each time the data service data are being received.

[216] When a data service request is transmitted through the user interface, the data broadcasting application manager 2013 operates the corresponding application program stored in the first memory 2009 so as to process the requested data, thereby providing the user with the requested data service. And, in order to provide such data service, the data broadcasting application manager 2013 supports the graphic user interface (GUI). Herein, the data service may be provided in the form of text (or short message service (SMS)), voice message, still image, and moving image. The data broadcasting application manager 2013 may be provided with a platform for executing the application program stored in the first memory 2009. The platform may be, for example, a Java virtual machine for executing the Java program. Hereinafter, an example of the data broadcasting application manager 2013 executing the data service providing application program stored in the first memory 2009, so as to process the data service data stored in the second memory 2011, thereby providing the user with the corresponding data service will now be described in detail.

[217] Assuming that the data service corresponds to a traffic information service, the data service according to the present invention is provided to the user of a receiving system that is not equipped with an electronic map and/or a GPS system in the form of at least one of a text (or short message service (SMS)), a voice message, a graphic message, a still image, and a moving image. In this case, is a GPS module is mounted on the receiving system shown in FIG. 14, the GPS module receives satellite signals transmitted from a plurality of low earth orbit satellites and extracts the current position (or location) information (e.g., longitude, latitude, altitude), thereby outputting the extracted information to the data broadcasting application manager 2013.

[218] At this point, it is assumed that the electronic map including information on each link and nod and other diverse graphic information are stored in one of the second memory 2011, the first memory 2009, and another memory that is not shown. More specifically, according to the request made by the data broadcasting application manager 2013, the data service data stored in the second memory 2011 are read and inputted to the data broadcasting application manager 2013. The data broadcasting application manager 2013 translates (or deciphers) the data service data read from the second memory 2011, thereby extracting the necessary information according to the contents of the message and/or a control signal.

[219] FIG. 15 illustrates a block diagram showing the structure of a digital broadcast (or television) receiving system according to another embodiment of the present invention. Referring to FIG. 15, the digital broadcast receiving system includes a tuner 3001, a demodulating unit 3002, a demultiplexer 3003, a first descrambler 3004, an audio decoder 3005, a video decoder 3006, a second descrambler 3007, an authentication unit 3008, a native TV application manager 3009, a channel manager 3010, a channel map 3011, a first memory 3012, a data decoder 3013, a second memory 3014, a system manager 3015, a data broadcasting application manager 3016, a storage controller 3017, a third memory 3018, and a telecommunication module 3019. Herein, the third memory 3018 is a mass storage device, such as a hard disk drive (HDD) or a memory chip. Also, during the description of the digital broadcast (or television or DTV) receiving system shown in FIG. 15, the components that are identical to those of the digital broadcast receiving system of FIG. 14 will be omitted for simplicity.

[220] As described above, in order to provide services for preventing illegal duplication

(or copies) or illegal viewing of the enhanced data and/or main data that are transmitted by using a broadcast network, and to provide paid broadcast services, the transmitting system may generally scramble and transmit the broadcast contents. Therefore, the receiving system needs to descrample the scrambled broadcast contents in order to provide the user with the proper broadcast contents. Furthermore, the receiving system may generally be processed with an authentication process with an anuthnetication means before the descrambling process. Hereinafter, the receiving system including an authentication means and a descrambling means according to an embodiment of the present invention will now be described in detail.

[221] According to the present invention, the receiving system may be provided with a descrambling means receiving scrambled broadcasting contents and an authentication means authenticating (or verifying) whether the receiving system is entitled to receive the descrambled contents. Hereinafter, the descrambling means will be referred to as first and second descramblers 3004 and 3007, and the authentication means will be referred to as an authentication unit 3008. Such naming of the corresponding components is merely exemplary and is not limited to the terms suggested in the description of the present invention. For example, the units may also be referred to as a decryptor. Although FIG. 15 illustrates an example of the descramblers 3004 and 3007 and the authentication unit 3008 being provided inside the receiving system, each of the descramblers 3004 and 3007 and the authentication unit 3008 may also be separately provided in an internal or external module. Herein, the module may include a slot type, such as a SD or CF memory, a memory stick type, a USB type, and so on, and may be detachably fixed to the receiving system. [222] As described above, when the authentication process is performed successfully by the authentication unit 3008, the scrambled broadcasting contents are descrambled by the descramblers 3004 and 3007, thereby being provided to the user. At this point, a variety of the authentication method and descrambling method may be used herein. However, an agreement on each corresponding method should be made between the receiving system and the transmitting system. Hereinafter, the authentication and de- scrambling methods will now be described, and the description of identical components or process steps will be omitted for simplicity.

[223] The receiving system including the authentication unit 3008 and the descramblers

3004 and 3007 will now be described in detail. The receiving system receives the scrambled broadcasting contents through the tuner 3001 and the demodulating unit 3002. Then, the system manager 3015 decides whether the received broadcasting contents have been scrambled. Herein, the demodulating unit 3002 may be included as a demodulating means according to embodiments of the present invention as described in FIG. 11 and FIG. 13. However, the present invention is not limited to the examples given in the description set forth herein. If the system manager 3015 decides that the received broadcasting contents have been scrambled, then the system manager 3015 controls the system to operate the authentication unit 3008. As described above, the authentication unit 3008 performs an authentication process in order to decide whether the receiving system according to the present invention corresponds to a legitimate host entitled to receive the paid broadcasting service. Herein, the authentication process may vary in accordance with the authentication methods.

[224] For example, the authentication unit 3008 may perform the authentication process by comparing an IP address of an IP datagram within the received broadcasting contents with a specific address of a corresponding host. At this point, the specific address of the corresponding receiving system (or host) may be a MAC address. More specifically, the authentication unit 3008 may extract the IP address from the de- capsulated IP datagram, thereby obtaining the receiving system information that is mapped with the IP address. At this point, the receiving system should be provided, in advance, with information (e.g., a table format) that can map the IP address and the receiving system information. Accordingly, the authentication unit 3008 performs the authentication process by determining the conformity between the address of the corresponding receiving system and the system information of the receiving system that is mapped with the IP address. In other words, if the authentication unit 3008 determines that the two types of information conform to one another, then the authentication unit 3008 determines that the receiving system is entitled to receive the corresponding broadcasting contents.

[225] In another example, standardized identification information is defined in advance by the receiving system and the transmitting system. Then, the identification information of the receiving system requesting the paid broadcasting service is transmitted by the transmitting system. Thereafter, the receiving system determines whether the received identification information conforms with its own unique identification number, so as to perform the authentication process. More specifically, the transmitting system creates a database for storing the identification information (or number) of the receiving system requesting the paid broadcasting service. Then, if the corresponding broadcasting contents are scrambled, the transmitting system includes the identification information in the EMM, which is then transmitted to the receiving system.

[226] If the corresponding broadcasting contents are scrambled, messages (e.g., entitlement control message (ECM), entitlement management message (EMM)), such as the CAS information, mode information, message position information, that are applied to the scrambling of the broadcasting contents are transmitted through a corresponding data header or anther data packet. The ECM may include a control word (CW) used for scrambling the broadcasting contents. At this point, the control word may be encoded with an authentication key. The EMM may include an authentication key and entitlement information of the corresponding data. Herein, the authentication key may be encoded with a receiving system-specific distribution key. In other words, assuming that the enhanced data are scrambled by using the control word, and that the authentication information and the descrambling information are transmitted from the transmitting system, the transmitting system encodes the CW with the authentication key and, then, includes the encoded CW in the entitlement control message (ECM), which is then transmitted to the receiving system. Furthermore, the transmitting system includes the authentication key used for encoding the CW and the entitlement to receive data (or services) of the receiving system (i.e., a standardized serial number of the receiving system that is entitled to receive the corresponding broadcasting service or data) in the entitlement management message (EMM), which is then transmitted to the receiving system.

[227] Accordingly, the authentication unit 3008 of the receiving system extracts the identification information of the receiving system and the identification information included in the EMM of the broadcasting service that is being received. Then, the authentication unit 3008 determines whether the identification information conform to each other, so as to perform the authentication process. More specifically, if the authentication unit 3008 determines that the information conform to each other, then the authentication unit 3008 eventually determines that the receiving system is entitled to receive the request broadcasting service.

[228] In yet another example, the authentication unit 3008 of the receiving system may be detachably fixed to an external module. In this case, the receiving system is interfaced with the external module through a common interface (CI). In other words, the external module may receive the data scrambled by the receiving system through the common interface, thereby performing the descrambling process of the received data. Alternatively, the external module may also transmit only the information required for the descrambling process to the receiving system. The common interface is configured on a physical layer and at least one protocol layer. Herein, in consideration of any possible expansion of the protocol layer in a later process, the corresponding protocol layer may be configured to have at least one layer that can each provide an independent function.

[229] The external module may either consist of a memory or card having information on the key used for the scrambling process and other authentication information but not including any descrambling function, or consist of a card having the above-mentioned key information and authentication information and including the descrambling function. Both the receiving system and the external module should be authenticated in order to provide the user with the paid broadcasting service provided (or transmitted) from the transmitting system. Therefore, the transmitting system can only provide the corresponding paid broadcasting service to the authenticated pair of receiving system and external module.

[230] Additionally, an authentication process should also be performed between the receiving system and the external module through the common interface. More specifically, the module may communicate with the system manager 3015 included in the receiving system through the common interface, thereby authenticating the receiving system. Alternatively, the receiving system may authenticate the module through the common interface. Furthermore, during the authentication process, the module may extract the unique ID of the receiving system and its own unique ID and transmit the extracted IDs to the transmitting system. Thus, the transmitting system may use the transmitted ID values as information determining whether to start the requested service or as payment information. Whenever necessary, the system manager 3015 transmits the payment information to the remote transmitting system through the telecommunication module 3019.

[231] The authentication unit 3008 authenticates the corresponding receiving system and/ or the external module. Then, if the authentication process is successfully completed, the authentication unit 3008 certifies the corresponding receiving system and/or the external module as a legitimate system and/or module entitled to receive the requested paid broadcasting service. In addition, the authentication unit 3008 may also receive authentication-associated information from a mobile telecommunications service provider to which the user of the receiving system is subscribed, instead of the transmitting system providing the requested broadcasting service. In this case, the authentication-association information may either be scrambled by the transmitting system providing the broadcasting service and, then, transmitted to the user through the mobile telecommunications service provider, or be directly scrambled and transmitted by the mobile telecommunications service provider. Once the authentication process is successfully completed by the authentication unit 3008, the receiving system may descramble the scrambled broadcasting contents received from the transmitting system. At this point, the descrambling process is performed by the first and second de- scramblers 3004 and 3007. Herein, the first and second descramblers 3004 and 3007 may be included in an internal module or an external module of the receiving system.

[232] The receiving system is also provided with a common interface for communicating with the external module including the first and second descramblers 3004 and 3007, so as to perform the descrambling process. More specifically, the first and second de- scramblers 3004 and 3007 may be included in the module or in the receiving system in the form of hardware, middleware or software. Herein, the descramblers 3004 and 3007 may be included in any one of or both of the module and the receiving system. If the first and second descramblers 3004 and 3007 are provided inside the receiving system, it is advantageous to have the transmitting system (i.e., at least any one of a service provider and a broadcast station) scramble the corresponding data using the same scrambling method.

[233] Alternatively, if the first and second descramblers 3004 and 3007 are provided in the external module, it is advantageous to have each transmitting system scramble the corresponding data using different scrambling methods. In this case, the receiving system is not required to be provided with the descrambling algorithm corresponding to each transmitting system. Therefore, the structure and size of receiving system may be simplified and more compact. Accordingly, in this case, the external module itself may be able to provide CA functions, which are uniquely and only provided by each transmitting systems, and functions related to each service that is to be provided to the user. The common interface enables the various external modules and the system manager 3015, which is included in the receiving system, to communicate with one another by a single communication method. Furthermore, since the receiving system may be operated by being connected with at least one or more modules providing different services, the receiving system may be connected to a plurality of modules and controllers.

[234] In order to maintain successful communication between the receiving system and the external module, the common interface protocol includes a function of periodically checking the status of the opposite correspondent. By using this function, the receiving system and the external module is capable of managing the status of each opposite cor- respondent. This function also reports the user or the transmitting system of any malfunction that may occur in any one of the receiving system and the external module and attempts the recovery of the malfunction.

[235] In yet another example, the authentication process may be performed through software. More specifically, when a memory card having CAS software downloaded, for example, and stored therein in advanced is inserted in the receiving system, the receiving system receives and loads the CAS software from the memory card so as to perform the authentication process. In this example, the CAS software is read out from the memory card and stored in the first memory 3012 of the receiving system. Thereafter, the CAS software is operated in the receiving system as an application program. According to an embodiment of the present invention, the CAS software is mounted on (or stored) in a middleware platform and, then executed. A Java middleware will be given as an example of the middleware included in the present invention. Herein, the CAS software should at least include information required for the authentication process and also information required for the descrambling process.

[236] Therefore, the authentication unit 3008 performs authentication processes between the transmitting system and the receiving system and also between the receiving system and the memory card. At this point, as described above, the memory card should be entitled to receive the corresponding data and should include information on a normal receiving system that can be authenticated. For example, information on the receiving system may include a unique number, such as a standardized serial number of the corresponding receiving system. Accordingly, the authentication unit 3008 compares the standardized serial number included in the memory card with the unique information of the receiving system, thereby performing the authentication process between the receiving system and the memory card.

[237] If the CAS software is first executed in the Java middleware base, then the authentication between the receiving system and the memory card is performed. For example, when the unique number of the receiving system stored in the memory card conforms to the unique number of the receiving system read from the system manager 3015, then the memory card is verified and determined to be a normal memory card that may be used in the receiving system. At this point, the CAS software may either be installed in the first memory 3012 upon the shipping of the present invention, or be downloaded to the first memory 3012 from the transmitting system or the module or memory card, as described above. Herein, the descrambling function may be operated by the data broadcasting application manger 3016 as an application program.

[238] Thereafter, the CAS software parses the EMM/ECM packets outputted from the demultiplexer 3003, so as to verify whether the receiving system is entitled to receive the corresponding data, thereby obtaining the information required for descrambling (i.e., the CW) and providing the obtained CW to the descramblers 3004 and 3007. More specifically, the CAS software operating in the Java middleware platform first reads out the unique (or serial) number of the receiving system from the corresponding receiving system and compares it with the unique number of the receiving system transmitted through the EMM, thereby verifying whether the receiving system is entitled to receive the corresponding data. Once the receiving entitlement of the receiving system is verified, the corresponding broadcasting service information transmitted to the ECM and the entitlement of receiving the corresponding broadcasting service are used to verify whether the receiving system is entitled to receive the corresponding broadcasting service. Once the receiving system is verified to be entitled to receive the corresponding broadcasting service, the authentication key transmitted to the EMM is used to decode (or decipher) the encoded CW, which is transmitted to the ECM, thereby transmitting the decoded CW to the descramblers 3004 and 3007. Each of the descramblers 3004 and 3007 uses the CW to descramble the broadcasting service.

[239] Meanwhile, the CAS software stored in the memory card may be expanded in accordance with the paid service which the broadcast station is to provide. Additionally, the CAS software may also include other additional information other than the information associated with the authentication and descrambling. Furthermore, the receiving system may download the CAS software from the transmitting system so as to upgrade (or update) the CAS software originally stored in the memory card. As described above, regardless of the type of broadcast receiving system, as long as an external memory interface is provided, the present invention may embody a CAS system that can meet the requirements of all types of memory card that may be detachably fixed to the receiving system. Thus, the present invention may realize maximum performance of the receiving system with minimum fabrication cost, wherein the receiving system may receive paid broadcasting contents such as broadcast programs, thereby acknowledging and regarding the variety of the receiving system. Moreover, since only the minimum application program interface is required to be embodied in the embodiment of the present invention, the fabrication cost may be minimized, thereby eliminating the manufacturer's dependence on CAS manufacturers. Accordingly, fabrication costs of CAS equipments and management systems may also be minimized.

[240] Meanwhile, the descramblers 3004 and 3007 may be included in the module either in the form of hardware or in the form of software. In this case, the scrambled data that being received are descrambled by the module and then demodulated. Also, if the scrambled data that are being received are stored in the third memory 3018, the received data may be descrambled and then stored, or stored in the memory at the point of being received and then descrambled later on prior to being played (or reproduced). Thereafter, in case scramble/descramble algorithms are provided in the storage controller 3017, the storage controller 3017 scrambles the data that are being received once again and then stores the re-scrambled data to the third memory 3018.

[241] In yet another example, the descrambled broadcasting contents (transmission of which being restricted) are transmitted through the broadcasting network. Also, information associated with the authentication and descrambling of data in order to disable the receiving restrictions of the corresponding data are transmitted and/or received through the telecommunications module 3019. Thus, the receiving system is able to perform reciprocal (or two-way) communication. The receiving system may either transmit data to the telecommunication module within the transmitting system or be provided with the data from the telecommunication module within the transmitting system. Herein, the data correspond to broadcasting data that are desired to be transmitted to or from the transmitting system, and also unique information (i.e., identification information) such as a serial number of the receiving system or MAC address.

[242] The telecommunication module 3019 included in the receiving system provides a protocol required for performing reciprocal (or two-way) communication between the receiving system, which does not support the reciprocal communication function, and the telecommunication module included in the transmitting system. Furthermore, the receiving system configures a protocol data unit (PDU) using a tag-length-value (TLV) coding method including the data that are to be transmitted and the unique information (or ID information). Herein, the tag field includes indexing of the corresponding PDU. The length field includes the length of the value field. And, the value field includes the actual data that are to be transmitted and the unique number (e.g., identification number) of the receiving system.

[243] The receiving system may configure a platform that is equipped with the Java platform and that is operated after downloading the Java application of the transmitting system to the receiving system through the network. In this case, a structure of downloading the PDU including the tag field arbitrarily defined by the transmitting system from a storage means included in the receiving system and then transmitting the downloaded PDU to the telecommunication module 3019 may also be configured. Also, the PDU may be configured in the Java application of the receiving system and then outputted to the telecommunication module 3019. The PDU may also be configured by transmitting the tag value, the actual data that are to be transmitted, the unique information of the corresponding receiving system from the Java application and by performing the TLV coding process in the receiving system. This structure is advantageous in that the firmware of the receiving system is not required to be changed even if the data (or application) desired by the transmitting system is added.

[244] The telecommunication module within the transmitting system either transmits the

PDU received from the receiving system through a wireless data network or configures the data received through the network into a PDU which is transmitted to the host. At this point, when configuring the PDU that is to be transmitted to the host, the telecommunication module within the transmitting end may include unique information (e.g., IP address) of the transmitting system which is located in a remote location. Additionally, in receiving and transmitting data through the wireless data network, the receiving system may be provided with a common interface, and also provided with a WAP, CDMA Ix EV-DO, which can be connected through a mobile telecommunication base station, such as CDMA and GSM, and also provided with a wireless LAN, mobile internet, WiBro, WiMax, which can be connected through an access point. The above-described receiving system corresponds to the system that is not equipped with a telecommunication function. However, a receiving system equipped with telecommunication function does not require the telecommunication module 3019.

[245] The broadcasting data being transmitted and received through the above-described wireless data network may include data required for performing the function of limiting data reception. Meanwhile, the demultiplexer 3003 receives either the realtime data outputted from the demodulating unit 3002 or the data read from the third memory 3018, thereby performing demultiplexing. In this embodiment of the present invention, the demultiplexer 3003 performs demultiplexing on the enhanced data packet. Similar process steps have already been described earlier in the description of the present invention. Therefore, a detailed of the process of demultiplexing the enhanced data will be omitted for simplicity.

[246] The first descrambler 3004 receives the demultiplexed signals from the demultiplexer 3003 and then descrambles the received signals. At this point, the first de- scrambler 3004 may receive the authentication result received from the authentication unit 3008 and other data required for the descrambling process, so as to perform the descrambling process. The audio decoder 3005 and the video decoder 3006 receive the signals descrambled by the first descrambler 3004, which are then decoded and outputted. Alternatively, if the first descrambler 3004 did not perform the de- scrambling process, then the audio decoder 3005 and the video decoder 3006 directly decode and output the received signals. In this case, the decoded signals are received and then descrambled by the second descrambler 3007 and processed accordingly.

[247] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modi- fications and variations of this invention provided they come within the scope of the appended claims and their equivalents. [248] [249]

Claims

[1] A method of processing data in a transmitting system, the method comprising: composing enhanced data packets including at least one of enhanced data having information and known data previously determined in transmitting/receiving ends, and multiplexing the enhanced data packets with main data packets; determining a place of known data for initializing a memory of a post- Trellis encoder at a start portion of known data stream in the enhanced data packet, on the basis of an output sequence of interleaved data; inserting a plurality of RS parity place holders to the enhanced data packets, such that the plurality of RS parity place holders are outputted later than the known data for initialization, on the basis of the output sequence of interleaved data, and performing data interleaving based on the insertion; performing additional encoding, based on block coding fashion, for only enhanced data in the enhanced data packets which are outputted after performing data interleaving, and outputting the remaining data which has not undergone the additional encoding; and performing Trellis encoding for the data outputted from the enhanced encoding step and then outputting it.

[2] The method as set forth in claim 1, wherein the trellis encoding step includes the steps of: performing data interleaving after a plurality of non-systematic RS parities or RS parity place holder in inputted enhanced data packets; encoding Trellis encoding after performing memory initialization when the data after performing data interleaving is known data and is a start part of successive known data stream, and outputting the encoded result; and calculating the non-systematic RS parity using data in enhanced data packets before performing the data interleaving and data for memory initialization of the Trellis encoder, and then substituting the non-systematic RS parity or the RS parity place holder with the calculated result, to perform Trellis encoding.

[3] The method as set forth in claim 1, wherein the enhanced encoding step serves to output known data in the enhanced data packet or output data which is substituted with known data which is generated in a symbol region.

[4] The method as set forth in claim 1, wherein the enhanced encoding step includes the steps of: determining sizes of blocks on the basis of the known data for initialization; converting byte unit of inputted enhanced data to bit unit to remove a null bit for byte extension, and performing U/C encoding for the effective data bits on the basis of the determined block size, to output the U/C encoded data; and converting bit unit of the U/C encoded data to byte unit, to output the U/C encoded data byte.

[5] The method as set forth in claim 4, wherein the U and C indicate 1 and 2, respectively, and the step of performing block interleaving for the 1/2 encoded data is optional.

[6] A transmitting system comprising: a packet formatter/multiplexer for multiplexing main data packets with enhanced data packets to output the multiplexed result, in which the enhanced data packets include at least one of enhanced data having information and known data previously determined in transmitting/receiving ends; an RS parity place holder inserting/interleaving unit for inserting a plurality of

RS parity place holders to the enhanced data packets outputted from the packet formatter/multiplexer, to perform data interleaving; and an enhanced encoding unit for performing additional encoding, based on block coding fashion, for only enhanced data after performing data interleaving, for performing data de-interleaving, and removing RS parity place holders.

[7] The transmitting system as set forth in claim 6, wherein further comprising: a non-systematic RS parity place holder insertion unit/data interleaver for inserting a plurality of non-systematic RS parities or RS parity place holders in the output data of the enhanced encoding unit to perform data interleaving, and for outputting the result of the data interleaving to perform Trellis encoding; a Trellis encoding unit for encoding Trellis encoding after performing memory initialization when the data after performing data interleaving is known data and is a start part of successive known data stream, and outputting the encoded result, in which the Trellis encoding unit can perform initialization; and a compatible processor for re-calculating a non-systematic RS parity based on output of the non-systematic RS parity place holder insertion unit and the Trellis encoding unit, such that the non-systematic RS parity or the RS parity place holder, which is inputted by the Trellis encoding unit, is substituted with the recalculation result; and a transmitting unit for inserting synchronous symbol to the output of the Trellis encoding unit, and for modulating it to transmit the modulation result thereto.

[8] The transmitting system as set forth in claim 6, wherein: the packet formatter/multiplexer determines a place of known data for initializing a memory of a post- Trellis encoder at a start portion of known data stream in the enhanced data packet, on the basis of an output sequence of interleaved data; and the RS parity place holder inserting/interleaving unit for inserting a plurality of RS parity place holders to the enhanced data packets, such that the plurality of RS parity place holders are outputted later than the known data for initialization, on the basis of the output sequence of interleaved data, and for performing data interleaving based on the insertion.

[9] The transmitting system as set forth in claim 8, wherein the enhanced encoding unit includes: a U/C encoding unit for converting byte unit of inputted enhanced data to bit unit to remove a null bit for byte extension, and performing U/C encoding for the effective data bits on the basis of the determined block size, to output the U/C encoded data based on byte unit; a buffer for delaying inputted main data for a certain time, and then outputting it thereto; and a multiplexer for selecting one of the output data of the U/C encoding unit and the output data of the buffer, and then outputting the selected output data.

[10] The transmitting system as set forth in claim 9, wherein the block size is determined on the basis of the known data region for initialization.

[11] The transmitting system as set forth in claim 10, wherein the block size is determined by the bit number of enhanced data between the known data region for initialization and another known data region for initialization.

[12] The transmitting system as set forth in claim 9, wherein: the U and C indicate 1 and 2, respectively, and a block interleaver, which performs block interleaving for the 1/2 encoded data, is selectively used.

[13] The transmitting system as set forth in claim 9, wherein the buffer delays inputted known data for a certain time and then outputs it through the multiplexer.

[14] The transmitting system as set forth in claim 9, wherein the multiplexer selects known data generated in symbol region instead of known data outputted from the RS parity place holder inserting/interleaving unit, and the outputs it thereto.

[15] The transmitting system as set forth in claim 8, wherein the enhanced encoding unit includes: an N- way interleaver for classifying inputted enhanced data based on N unit, and distributing the N enhanced data on the basis of predetermined sequence; an N- way deinterleaver for deinterleaving the symbols outputted from N enhanced encoding units which are arranged in parallel, in which the enhanced encoding unit converts the symbols distributed in the N- way interleaver to bit units, removes a null bit for byte extension, performs U/C encoding for effective data bits based on a predetermined size, dividing block size by N, and outputting the encoding result based on symbol unit; a buffer for delaying inputted main data for a certain time, and then outputting it thereto; and a multiplexer for selecting one of the output data of the N-way deinterleaver and the output data of the buffer, and then outputting the selected output data.

[16] The transmitting system as set forth in claim 15, wherein the block size is determined on the basis of the known data region for initialization.

[17] The transmitting system as set forth in claim 16, wherein the block size is determined by the bit number of enhanced data between the known data region for initialization and another known data region for initialization.

[18] The transmitting system as set forth in claim 15, wherein the buffer delays inputted known data for a certain time and then outputs it through the multiplexer.

[19] The transmitting system as set forth in claim 15, wherein the multiplexer selects known data generated in a symbol region instead of known data outputted from the RS parity place holder inserting/interleaving unit, and the outputs it thereto.

[20] An enhanced encoding device of a transmitting system, comprising: a U/C encoding unit for converting byte unit of inputted enhanced data to bit unit to remove a null bit for byte extension, and performing U/C encoding for the effective data bits on the basis of the determined block size, to output the U/C encoded data based on byte unit; a buffer for delaying remaining data except for the enhance data for a certain time, and then outputting them thereto; and a multiplexer for selecting one of the output data of the U/C encoding unit and the output data of the buffer, and then outputting the selected output data.

[21] The enhanced encoding device as set forth in claim 20, wherein the block size is determined by the bit number of enhanced data between the known data region for initialization and another known data region for initialization.

[22] The enhanced encoding device as set forth in claim 20, wherein: the U and C indicate 1 and 2, respectively, and a block interleaver, which performs block interleaving for the 1/2 encoded data, is selectively used.

[23] The enhanced encoding device as set forth in claim 20, wherein the multiplexer selects known data generated in a symbol region instead of known data outputted from the buffer, and the outputs it thereto.

[24] An enhanced encoding device of a transmitting system, comprising: an N-way interleaver for classifying inputted enhanced data based on N unit, and distributing the N enhanced data on the basis of predetermined sequence; an N-way deinterleaver for deinterleaving the symbols outputted from N enhanced encoding units which are arranged in parallel, in which the enhanced encoding unit converts the symbols distributed in the N-way interleaver to bit units, removes a null bit for byte extension, performs U/C encoding for effective data bits based on a predetermined size, dividing block size by N, and outputting the encoding result based on symbol unit; a buffer for delaying remaining data except for the enhanced data for a certain time, and then outputting it thereto; and a multiplexer for selecting one of the output data of the N-way deinterleaver and the output data of the buffer, and then outputting the selected output data.

[25] The enhanced encoding device as set forth in claim 24, wherein the block size is determined by the bit number of enhanced data between the known data region for initialization and another known data region for initialization.

[26] The enhanced encoding device as set forth in claim 24, wherein the multiplexer selects known data generated in a symbol region instead of known data outputted from the buffer, and the outputs it thereto.

[27] A receiving system comprising: a demodulating/equalizing unit for performing demodulation and channel equalization as signals transmitted from the transmitting system are received through a tuning operation, and known data information is applied to the received signals; an enhanced decoder for performing soft determination decoding and decoding of block coding fashion as known data information is applied to the channel equalized enhanced data; and a known data detecting/generating unit for detecting the known data information, which is inserted in the transmitting end, from signals before demodulation or after modulation, and outputting the detection result to the demodulating/ equalizing unit and the enhanced decoder.

[28] The receiving system as set forth in claim 27, wherein the enhanced decoder outputs a hard determination value thereto when the received data is main data or known data.

[29] The receiving system as set forth in claim 27, wherein the enhanced decoder includes: a Trellis decoder for performing soft determination for inputted enhanced data; and a U/C decoder for determining the start and end of a block size from the known data information, and decoding the soft determination value of the Trellis decoder using the determined information, in which the decoding of the U/C decoder is a reverse process of the encoding of the block coding fashion of the transmitting end.