WO2006006830A1

WO2006006830A1 - Apparatus and method for generating pseudo pilot pseudo noise, and wireless relay system

Info

Publication number: WO2006006830A1
Application number: PCT/KR2005/002262
Authority: WO
Inventors: Young Chan Kim; Jin Seok Yang; Gi Ju Rho
Original assignee: Hantel Co., Ltd.
Priority date: 2004-07-14
Filing date: 2005-07-14
Publication date: 2006-01-19
Also published as: KR20060005918A; JP2008507193A

Abstract

Provided are an apparatus and method for generating a pseudo pilot pseudo noise (PN), a wireless relay system using the same, and a computer-readable recording medium that records program for executing the method. The wireless relay system includes: a pseudo pilot pseudo noise (PN) generator for determining position and size of a pilot pseudo noise (PN) to be inserted by searching for pilot PNs of base station signals on one side that are branched off at an end side and generating a pseudo pilot PN; a receiver for receiving the base station signals coming from a plurality of base stations through multiple paths; a pseudo pilot PN inserter for inserting the pseudo pilot PN received from the pseudo pilot PN generator into a base station signal to relay among the base station signals received through the receiver; a relay for receiving the base station signals to which the pseudo pilot PN is inserted from the pseudo pilot PN inserter and relaying the received base station signals; a signal branch for branching off the base station signals received from the relay and transferring the base station signals on one side to the pseudo pilot PN generator; and a transmitter for receiving base station signals on the other side to which a pseudo pilot PN is inserted from the signal branch and transmitting the base station signals.

Description

APPARATUS AND METHOD FOR GENERATING PSEUDO PILOT PSEUDO NOISE, AND WIRELESS RELAY SYSTEM

USING THE SAME

Technical Field

[1] The present invention relates to an apparatus and method for generating pseudo pilot pseudo noise (PN), a wireless relay system using the same, and a computer- readable recording medium storing a program for executing the method. More par¬ ticularly, the present invention relates to a pseudo pilot PN generating apparatus and method thereof, a wireless relay system using the same, and a computer-readable recording medium storing a program for executing the method, capable of solving problems of reduced quality of speech, failed reception, and reduced base station capacity due to frequent hand-off caused by simultaneously relaying signals of various base stations through a wireless relay system in a current complicated wireless com¬ munication network.

Background Art

[2] In the present invention, pilot pseudo noise (PN) refers to a short PN code loaded on a pilot channel in a scheme of a code division multiple access (CDMA) com¬ munication or wideband CDMA, for example. The pilot PN is used to discriminate a base station with a unit of 64-chip interval.

[3] Further, the pseudo pilot PN in the present invention refers to not a pilot PN that is actually searched from a base station signal, but a pilot PN that is generated according to the present invention and inserted into the base station signal so as to be used as a reference when performing demodulation or a handoff at the terminal side.

[4] A wireless relay system in the present invention refers to a system that receives a base band signal wirelessly from the base station and relays the base band signal to a shadow region.

[5] Here, the term shadow area means an area where a radio path between the base station and a terminal is obstructed. That is, it refers to an area that a radio signal from the base station cannot reach due to surrounding structures or landscape. In order to remove the shadow area, new base stations are additionally installed or the wireless network is designed using a relay system.

[6] However, it is not efficient to remove the shadow area by increasing the number of base station since that would require a large investment. Accordingly, the relay system is widely used, and can provide high-quality communication at a low cost and with improved service coverage. That is, although the base station is superior to the relay system performance- wise, it has the drawback of being more costly than the relay system. Accordingly, the relay system is generally used to remove a small shadow area.

[7] Meanwhile, an existing wireless relay may be a general relay in a radio frequency

(RF) scheme, a microwave relay using microwaves, a small base station, a wireless optical relay using a wireless optical signal, and the like.

[8] FIGS. Ia to Id are views of an exemplary conventional wireless relay system.

[9] First, a general relay 11 shown in FIG. Ia receives a radio frequency signal of a wireless communication band from a parent base station, amplifies it, and transmits (radiates) the amplified signal to a shadow area.

[10] Further, a microwave relay 12 shown in FIG. Ib converts the RF signal into a signal having a microwave frequency (8-30GHz) using a small microwave transmission device between the parent base station and a small cell and transmits it.

[11] The small base station 13 shown in FIG. Ic is a miniaturized version of a general base station of a wireless communication system

[12] Finally, a wireless optical relay shown in FIG. Id includes a donor device 14 for converting a radio frequency signal transmitted from the base station into an optical signal, and a coverage device 15 for receiving an optical signal from the donor device 14, converting it into a radio frequency signal, and transmitting the converted signal. Disclosure of Invention

Technical Problem

[13] However, in the conventional wireless relay system, together with the base station signal being relayed to, an undesired signal of another base station is sometimes received, amplified, and transmitted into a service area of the wireless relay system are come into, amplified and transmitted. Accordingly, the signal of the other base station operates as reception noise in a terminal located in the service area of the cor¬ responding wireless relay system.

[14] Such a phenomenon may cause a more serious problem as an interval between base stations becomes narrower due to an increasing number of subscribers.

[15] That is, even in recent times, since there is a scramble for many base station signals coming into the wireless relay located downtown where an interval between nearby base stations is narrow due to a large number of subscribers, the other base station signal becomes a cause of bad reception in standby mode, speech quality reduction, and reduction of base station capacity. This is because there are frequent hand-off requests of the terminal depending on the change of signal level of each base station input into a wireless relay.

Technical Solution [16] It is, therefore, an object of the present invention to provide an apparatus and method for generating a pseudo pilot PN, and a computer-readable recording medium in which program for executing the method is recoded, capable of searching for a pilot PNs of various base station signals coming to a wireless relay, determining position and size of the pilot PN to be inserted to a signal of the base station to relay, and generating the pseudo pilot PN.

[17] It is another object of the present invention to provide a wireless relay system capable of transmitting a desired pilot PN of the base station among various base station signals, a level of the desired pilot PN being higher than those of the pilot PNs of other base stations.

[18] Further objects and advantages of the present invention can be more fully understood from the following detailed description and will be apparent through an embodiment of the present invention. Further, it can be understood that the objects and advantages of the present invention are embodied by means and their combination of them shown in claims.

[19] According to an aspect of the present invention, there is provided a pseudo pilot PN generating apparatus including: a frequency down converter for receiving base station signals to relay and converting the base station signals downward in frequency according to control of a controller; a demodulator for demodulating the base station signals that are converted downward in frequency in the frequency down converter; a searcher for searching for all of the pilot PNs of the base station signals demodulated in the demodulator; a controller for receiving a result of searching the pilot PNs of the base station signals in the searcher and determining position and size of the pilot PN to insert; a pseudo pilot PN generator for receiving the position and size of the pilot PN determined in the controller and generating the pseudo pilot PN caused by the reception; a modulator for modulating the pseudo pilot PN signal generated in the pseudo pilot PN generator; and a frequency up converter for converting the pseudo pilot PN signal modulated in the modulator upward in frequency according to the control of the controller and outputting the converted pseudo pilot PN signal to be inserted into the base station signals to relay.

[20] The controller may further calculate and search for position and size errors of the pseudo pilot PN inserted already after receiving a result of searching the pilot PN of the base station signals including the pseudo pilot PN in the searcher and transfer the result to the pseudo pilot PN generator.

[21] According to another aspect of the present invention, there is provided a method for generating a pseudo pilot PN, including the steps of: selecting a frequency assignment (FA) after initializing a search and a pseudo pilot PN generator; allowing the search to search for (detect) all of pilot PNs according to a PN offset value; determining position and size of the pilot PN to be inserted, using a result of searching for (detecting) the pilot PN in the search; and generating a pseudo pilot PN by transferring the determined position and size of the pilot PN to the pseudo pilot PN generator.

[22] The method may further include the steps of: allowing the search to search for

(detect) pilot PNs of the base station signals including the pseudo pilot PN; calculating the position and size errors of the pseudo pilot PN inserted already using a result of searching for the pilot PN of the base station signals including the pseudo pilot PN in the search; and regulating the calculated position and size errors of the pseudo pilot PN and then relaying from the step of generating the pseudo pilot PN.

[23] According to still another aspect of the present invention, there is provided a computer-readable recording medium containing program for executing, on a micro¬ processor to generate a pseudo pilot PN, the functions of: selecting a frequency assignment (FA) after initializing a search and a pseudo pilot PN generator; allowing the search to search for (detect) all of pilot PNs according to a PN offset value; de¬ termining position and size of the pilot PN to be inserted, using a result of searching for (detecting) the pilot PN in the search; and generating a pseudo pilot PN by transferring the determined position and size of the pilot PN to the pseudo pilot PN generator.

[24] The recording medium may further include the functions of: allowing the search and pseudo pilot PN generator to search for (detect) pilot PNs of the base station signals (including the pseudo pilot PN); calculating the position and size errors of the pseudo pilot PN inserted already using a result of searching for the pilot PN of the base station signals (including the pseudo pilot PN) in the search and pseudo pilot PN generator; and regulating the position and size errors of the pseudo pilot PN calculated and then relaying the steps starting from the step of generating the pseudo pilot PN.

[25] According to yet another aspect of the present invention, there is provided a pseudo pilot pseudo noise (PN) generator for determining position and size of a pilot pseudo noise (PN) to be inserted by searching for pilot PNs of base station signals on one side that are branched off at an end side and generating a pseudo pilot PN; a receiver for receiving the base station signals coming from a plurality of base stations through multiple paths; a pseudo pilot PN inserter for inserting the pseudo pilot PN received from the pseudo pilot PN generator into a base station signal to relay among the base station signals received through the receiver; a relay for receiving the base station signals to which the pseudo pilot PN is inserted from the pseudo pilot PN inserter and relaying the received base station signals; a signal branch for branching off the base station signals received from the relay and transferring the base station signals on one side to the pseudo pilot PN generator; and a transmitter for receiving base station signals on the other side to which a pseudo pilot PN is inserted from the signal branch and transmitting the base station signals

[26] The pseudo pilot PN generator may further search for the pilot PNs of the base station signals after receiving the base station signals on one side to which the pseudo pilot PN is inserted from the signal branch, generate the pseudo pilot PN by calculating and regulating position and size errors of the pseudo pilot PN that is already inserted, and transfer the pseudo pilot PN to the pseudo pilot PN inserter.

[27] As such, according to the present invention, a pilot PN that is a reference of de¬ modulation and handoff of a terminal among all of the base station signals input to a wireless relay is searched and a pilot PN of the base station signal to be serviced is transmitted higher than the pilot PNs of other base stations, so that a reception failure in a standby state can be prevented and a quality of speech is improved, thereby removing a shadow area caused by a PN pollution, a frequent hand-off of a terminal in a service area can be prevented, and a problem that base station capacity is reduced can be solved.

[28] That is, according to the present invention, a stable call process base is constructed by searching for pilot pseudo noises (PNs) of various base station signals incoming to a wireless relay, determining position and size of the pilot PN to insert, generating a pseudo pilot PN, inserting the determined size of pilot PN into the determined position within the pilot PN area of the base station to relay, and resultantly making the pilot PN of the base station to relay higher than the pilot PNs of the other base stations.

[29] Further, according to the present invention, in case that a capacity of the base station that is currently on the service is overloaded, a traffic can be distributed among base stations by searching for a pilot PN of various base station signals incoming to a wireless relay, determining position and size of the pilot PN to insert, generating a pseudo pilot PN, inserting the pseudo pilot PN generated newly in the determined size in the newly determined position within the pilot PN area of the base station to relay, and switching a terminal on service to a relay service of the other new base station without a call extinction.

[30] Further, in the process of determining the position and size of the pilot PN to insert, the position to which the pseudo pilot PN is inserted should be in the area that is recognized as the same pilot PN of the base station to relay, and should have searching energy higher than that of pilot PN of the other base station.

Advantageous Effects

[31] According to the present invention, a pilot PN that is a reference of demodulation and handoff of a terminal among all of the base station signals input to a wireless relay is searched and a pilot PN of the base station signal to be serviced is transmitted higher than the pilot PNs of other base stations, so that a reception failure in a standby state can be prevented and a quality of speech is improved, thereby removing a shadow area caused by a PN pollution, a frequent hand-off of a terminal in a service area can be prevented, and a problem that base station capacity is reduced can be solved.

[32] That is, in accordance with the present invention, a stable call process base can be constructed in a service area of the wireless relay by transmitting the pilot PN of the base station to be relayed higher than the pilot PNs of other base stations.

[33] Further, in accordance with the present invention, when the base station that is relayed currently is overloaded, current service can be converted into other base station nearby without call extinction of the serviced terminal so that traffic can be distributed among base stations.

[34] While the present invention has been described with reference to exemplary em¬ bodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the present invention as defined by the following claims.

Description of Drawings

[35] FIGS. IA to ID are exemplary views of a conventional wireless relay system.

[36] FIG. 2 is a conventional searching energy distribution diagram of a pilot pseudo noise (PN) to a time axis.

[37] FIG. 3 is a searching energy distribution diagram of a pilot pseudo noise (PN) including a pseudo pilot PN to a time axis in accordance with the present invention.

[38] FIG. 4 is a block diagram illustrating an embodiment of an apparatus for generating a pseudo pilot PN and a wireless relay system using the same in accordance with the present invention.

[39] FIG. 5 is a flow chart illustrating one embodiment of a method of generating a pseudo pilot PN in accordance with the present invention.

Mode for Invention

[40] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

[41] FIG. 2 is a conventional searching energy distribution diagram of a pilot pseudo noise (PN) to a time axis, and FIG. 3 is a searching energy distribution diagram of a pilot pseudo noise (PN) including a pseudo pilot PN to a time axis in accordance with the present invention.

[42] Generally, a short pseudo noise (PN) code loaded on a pilot channel (pilot PN) in a code division multiple access (CDMA) communication system or a wideband code division multiple access (WCDMA) communication system operates to discriminate each base station using a time offset.

[43] Further, when there exist several base stations around a wireless relay system, if a pilot pseudo noise (PN) is searched in signals coming into a wireless relay, it is possible to obtain a searching energy distribution diagram of the pilot PN to a time axis as shown in FIG. 2.

[44] At this time, the pilot PN is used to discriminate a base station in a 64-chip interval unit, and there exist several searching positions caused by multiple paths from the base station to a terminal in the 64-chip interval. In FIG. 2, searching energy denoted as numerals '201' and '202' means base stations different from each other, and #N (N being a natural number) means the number of signals that are sent from the same base station and pass through the multiple paths.

[45] Meanwhile, when there exist several base stations around the wireless relay system in accordance with the present invention, if a pilot pseudo noise (PN) is searched in signals coming into a wireless relay, it is possible to obtain a searching energy dis¬ tribution diagram of the pilot PN to the time axis as shown in FIG. 3. At this time, searching energy denoted as numerals '301' and '302' means base stations different from each other, and #N (N being a natural number) means the number of signals that are sent from the same base station and pass through the multiple paths.

[46] Further, numeral '303' in FIG. 3 represents a pseudo pilot PN that is forcibly inserted into a signal of a base station to relay using a pseudo pilot PN generating apparatus in accordance with the present invention.

[47] Meanwhile, the terminal employs a rake receiver structure in consideration of the effect of the multiple paths, which generally includes 4 fingers. At this time, several multiple path signals determined as the same base station signal by a searcher are assigned to the fingers depending on their positions, wherein a signal having high searching energy is preferentially assigned.

[48] Accordingly, a position to which the pseudo pilot PN 303 is inserted in FIG. 3 should be within an area that is recognized as the same pilot PN as that of the base station to be relayed, and the pseudo pilot PN 303 should have a higher searching energy than the pilot PNs of other base stations including '302'.

[49] FIG. 4 is a block diagram illustrating an embodiment of an apparatus of generating a pseudo pilot PN and a wireless relay system using the same in accordance with the present invention.

[50] Hereinafter, while the embodiment of the present invention is described taking an existing wireless communication RF relay (general relay) and a QPSK modulated base station signal as examples, the present invention should not be limited to the em¬ bodiments described herein.

[51] Referring to FIG. 4, the wireless relay system of the present invention includes a receiving antenna 410, a first coupler 420, a general relay 430, a second coupler 440, a transmitting antenna 450, and a pseudo pilot PN generating apparatus 460. [52] The receiving antenna 410 is a donor antenna, which receives a base station signal to relay together with undesired signals of other base stations which are incoming from a plurality of base stations adjacent to the wireless relay system through the multiple paths, and transfers the signals to the first coupler 420.

[53] The first coupler 420 receives a pseudo pilot PN generated by the pseudo pilot PN generating apparatus 460 and inserts it into the base station signal received through the receiving antenna 410. At this time, the pseudo pilot PN is inserted into the area that is recognized as the same pilot PN as that of the base station to relay, as is generated from the pseudo pilot PN generating apparatus 460 to be described later.

[54] According to the present invention, for example, the pseudo pilot PN is inserted into a position that is ahead of the foremost chip of the pilot PN of the base station by about 4 chips. Further, although an embodiment of the present invention describes a case where the pseudo pilot PN is coupled with the base station signal using the first coupler 420 and inserted, for example, it may also be embodied using a signal synthesizer, and so forth.

[55] The general relay 430 receives the base station signal to which the pseudo pilot PN is inserted from the first coupler 420, amplifies it and transfers the amplified signal to the second coupler 440. Here, one of a variety of kinds of wireless relays can be used as the general relay 430, and it operates in the same manner as existing various wireless relays expect an input signal, so that further explanation will be omitted here.

[56] The second coupler 440 branches off some of the base station signals amplified in the general relay 430 and transfers them to the pseudo pilot PN generating apparatus 460, and the rest of the base station signals are transferred to the transmitting antenna 450. Here, although an embodiment of the present invention describes a case where the base station signal is coupled using the second coupler 440 and some of the signals are extracted (branched off), for example, it may also be embodied using a signal distributor, a circulator, and so forth.

[57] The transmitting antenna 450 receives the base station signal to which the pseudo pilot PN is inserted from the second coupler 440 and transmits it to a shadow area. Ac¬ cordingly, the searcher of the terminal searches a pilot PN that becomes a reference of hand-off and demodulation of the terminal, and preferentially assigns a signal having high searching energy (a signal to which the pseudo pilot PN is inserted) to the finger.

[58] The pseudo pilot PN generating apparatus 460 searches for (detects) pilot PNs of several base station signals that are received through the second coupler 440, and determines position and size of the pilot PNs to be inserted. At this time, a position to which the determined pilot PN is inserted should be within an area that is recognized as the same pilot PN as that of the base station to relay (for example, a position that is ahead of the foremost chip of the pilot PN of the base station to relay by about 4 chips), and the determined pilot PN 303 has about 5% - 100% higher searching energy (preferably, about 20%) than the pilot PNs of other base stations having the highest searching energy. Here, the pilot PN may have a suitable value depending on the embodied environment.

[59] Further, the pseudo pilot PN generating apparatus 460 searches for (detects) the pilot PN of the various base station signals (including the pseudo pilot PN) received through the second coupler 440, and calculates and regulates position and size errors of the pseudo pilot PN inserted already. And then, it generates the pseudo pilot PN and transfers it to the first coupler 420. Although it is possible to insert the pseudo pilot PN into a correct position when the pseudo pilot PN is generated such that the pseudo pilot PN is inserted into a position that is ahead of the foremost chip of the pilot PN of the base station to relay by about 4 chips in consideration of the delay or the like initially, the procedure to calculate and regulate the position and size errors of the pseudo pilot PN inserted already is performed since the insertion may actually be have an error of about 1 chip. A more detailed description is as follows.

[60] First, an insertion position correction will be described below.

[61] As described above, while the position that is intended to be inserted is ahead of the foremost chip by 4 chips, when the pseudo pilot PN is detected ahead of the foremost chip by 5 chips as a result of researching, a microprocessor 467 commands the pseudo pilot PN generating apparatus 464 to generate the pseudo pilot after delaying one chip. On the contrary, when the pseudo pilot PN is detected ahead of the foremost chip by 3 chips, the microprocessor 467 commands to generate the pseudo pilot advancing by one chip. Meanwhile, although there occurs an error of two or more chips (2 or 3 chips) in the position that was intended first due to additional problems, the error correction is performed after delaying or advancing one chip. It is because a situation does not occur where there is excessiveness in the service due to the position, only if a position to which the pseudo pilot PN is inserted corresponds to an area that is recognized as the pilot PN of the same base station.

[62] Next, when reviewing the size correction, causes for the correction can be generally divided into two cases. One is a case that although an environment of signal coming into the general relay 430 is not changed, energy of the pseudo pilot PN that is inserted according to the present invention is different from the intended one, and the other is a case that although energy of the pseudo pilot PN inserted is the same as intended, its size should be regulated again due to the environment change of the signal coming to the general relay 430. However, it is not easy to discriminate that the size error is occurred in any cases from the viewpoint of the searching result only. Accordingly, target searching energy of the pseudo pilot PN is determined from the researching result (120% higher than the PN searching energy of the other base station that is changed as a result of the researching as initially shown), and it is determined how much the searching energy is increased or decreased on the basis of the searching energy of the pseudo pilot PN with respect to a current output level. Here, since the searching energy means power and is in proportion to the square of the signal magnitude, it is possible to determine how much the signal is increased or decreased when the searching energy and target searching energy with respect to the current signal magnitude. Further, the increase and decrease of the signal can be controlled using a digital gain of the pseudo pilot PN generator 464 and controlled by inserting a digital attenuator (not shown) into an external RF circuit, and both schemes are used to control them. At this time, even when the digital attenuator is used, it is controlled by the microprocessor 467.

[63] Meanwhile, the pseudo pilot PN generating apparatus 460 in accordance with the present invention includes a frequency down converter 461, a quadrature phase shift keying (QPSK) demodulator 462, a searcher 463, a pseudo pilot PN generator 464, a QPSK modulator 465, a frequency up converter 466 and a microprocessor 467.

[64] The frequency down converter 461 is a device performing a general frequency down function, which converts various base station signals some portions of whose output are branched off through the second coupler 440 downward in frequency according to the control (such as a PLL control) of the microprocessor 467 and transfers the converted signals to the QPSK demodulator 462. At this time, the frequency down converter 461 converts a high frequency signal of an RF band into an intermediate frequency (RF) band signal downward in frequency, for example, so that the high frequency signal can be processed.

[65] The QPSK demodulator 462 is a device performing a general QPSK demodulation function, which demodulates the various base band signals that are converted downward in frequency in the frequency down converter 461 and transfers the converted signals to the searcher 463.

[66] The searcher 463 is a device performing a general searching function, which searches for (detects) all of the pilot PNs of the various base station signals de¬ modulated in the QPSK demodulator 462 and transfers its result to the microprocessor 467.

[67] The microprocessor 467 receives the result of searching the pilot PN of the various base station signals from the searcher 463, determines the position and size of the pilot PN to be inserted and transfers its result to the pseudo pilot PN generator 464. At this time, the determined position and size of the pilot PN to be inserted are the same as described above.

[68] At this time, the microprocessor 467 further receives the result of searching for

(detecting) the pilot PNs of the various base station signals including the pseudo pilot PN from the searcher 463, calculates and regulates the position and size errors of the pseudo pilot PN inserted already, and transfers the result to the pseudo pilot PN generator 464. The reason is the same as described above.

[69] The pseudo pilot PN generator 464 is a device performing a general PN generation function, which receives the position and size of the pilot PN determined in the micro¬ processor 467, generates the pseudo pilot PN in response to the reception, and transfers the pseudo pilot PN to the QPSK modulator 465. At this time, the position and size of the generated pilot PN is the same as described above.

[70] The QPSK modulator 465 is a device performing a general QPSK modulation function, which performs QPSK modulation of the pseudo pilot PN signal generated in the pseudo pilot PN generator 464 and transfers the modulated signal to the frequency up converter 466.

[71] The frequency up converter 466 is a device performing a general frequency up function, which converts the pseudo pilot PN signals that are QPSK modulated in the QPSK modulator 465 upward in frequency according to the control (such as a PLL control) of the microprocessor 467 and transfers the converted signal to the first coupler 420. At this time, the frequency up converter 466 converts, for example, a signal of an IF band into a high frequency signal of a RF band.

[72] Further, although the QPSK modulation/demodulation schemes are described by way of an example in the one embodiment of the present invention, the modulation/ demodulation schemes used in a relayed base station signal may be practically applied.

[73] FIG. 5 is a flow chart of one embodiment of a method of generating a pseudo pilot

PN in accordance with the present invention, which shows a procedure to regulate correct insertion position and size of a pseudo pilot PN and generate the pseudo pilot PN.

[74] First, the microprocessor 467 initializes the searcher 463 and the pseudo pilot PN generator 464 (S510). Further, the microprocessor 467 selects a frequency assignment (FA) (S520).

[75] Subsequently, the microprocessor 467 controls the searcher 463 to search for

(detect) all of pilot PNs according to a PN offset value (S530).

[76] Next, the microprocessor 467 receives a result of searching for the pilot PN in the searcher 463 and determines the position and size of the pilot PN to be inserted (S540). At this time, the position and size of the determined pilot PN are the same as described above.

[77] Next, the microprocessor 467 transfers the determined position and size of the pilot

PN to the pseudo pilot PN generator 464 and then enable the pseudo pilot PN generator 464 to generate the pseudo pilot PN (S550). At this time, the position and size of the generated pseudo pilot PN are the same as described above. [78] Next, the microprocessor 467 controls the searcher 463 to search for the pilot PNs of the various base station signals including the pseudo pilot PN (S560).

[79] Next, the microprocessor 467 receives the result of searching for the pilot PNs of the various base station signal including the pseudo pilot PN from the searcher 463 and calculates the position and size errors of the pseudo pilot PN inserted already (S570).

[80] Next, the microprocessor 467 regulates the calculated position and size of the pseudo pilot PN (S580) and performs the pseudo pilot PN generation process (S570).

[81] As such, the microprocessor 467 performs an error correction of the determined insertion position and size of the pilot PN determined initially by relaying the processes described above (S550 to S580).

[82] The method of the present invention described above can be embodied as program and stored in recording medium (CD ROM, RAM, ROM, Floppy disk, hard disk, magneto-optical disk, and the like) in a format readable in computer. Such a procedure can be easily embodied by an ordinary person skilled in the art and therefore a further description will be omitted.

Claims

[1] 1. A wireless relay system comprising: a pseudo pilot pseudo noise (PN) generator for determining position and size of a pilot pseudo noise (PN) to be inserted by searching for pilot PNs of base station signals on one side that are branched off at an end side and generating a pseudo pilot PN; a receiver for receiving the base station signals coming from a plurality of base stations through multiple paths; a pseudo pilot PN inserter for inserting the pseudo pilot PN received from the pseudo pilot PN generator into a base station signal to relay among the base station signals received through the receiver; a relay for receiving the base station signals to which the pseudo pilot PN is inserted from the pseudo pilot PN inserter and relaying the received base station signals; a signal branch for branching off the base station signals received from the relay and transferring the base station signals on one side to the pseudo pilot PN generator; and a transmitter for receiving base station signals on the other side to which a pseudo pilot PN is inserted from the signal branch and transmitting the base station signals.

[2] 2. The wireless relay system as claimed in claim 1, wherein the pseudo pilot PN generator further searches for the pilot PNs of the base station signals after receiving the base station signals on one side to which the pseudo pilot PN is inserted from the signal branch, generates the pseudo pilot PN by calculating and regulating position and size errors of the pseudo pilot PN that is already inserted, and transfers the pseudo pilot PN to the pseudo pilot PN inserter.

[3] 3. The wireless relay system as claimed in claim 1 or 2, wherein the pseudo pilot

PN generator determines a position to which the pseudo pilot PN is inserted in order to insert the pseudo pilot PN into an area that is recognized as the same pilot PN as that of the base station to relay and generates a pseudo pilot PN.

[4] 4. The wireless relay system as claimed in claim 3, wherein the pseudo pilot PN generator determines the size of the pseudo pilot PN such that the pilot PN of the base station to relay has a searching energy higher than the highest searching energy of the pilot PN of the other base station and generates a pseudo pilot PN corresponding to the size.

[5] 5. The wireless relay system as claimed in claim 4, wherein the pseudo pilot PN generator comprises: a frequency down converter for receiving the base station signals on one side branched off in the signal branch and converting the received signals downward in frequency according to control of a microprocessor; a demodulator for demodulating the base station signals that are converted downward in frequency in the frequency down converter; a searcher for searching for all of the pilot PNs of the base station signals de¬ modulated in the demodulator; the microprocessor for receiving a result of searching the pilot PN of the base station signals in the searcher and determining the position and size of the pilot PN to insert; a pseudo pilot PN generator for receiving the position and size of the pilot PN determined in the microprocessor and generating a pseudo pilot PN caused by the reception; a modulator for modulating the pseudo pilot PN signal generated in the pseudo pilot PN generator; and a frequency up converter for converting the pseudo pilot PN signal modulated in the modulator upward in frequency according to control of the microprocessor and transferring the converted pseudo pilot PN signal to the pseudo pilot PN inserter.

[6] 6. A pseudo pilot PN generating apparatus comprising: a frequency down converter for receiving base station signals to relay and converting the base station signals downward in frequency according to control of a controller; a demodulator for demodulating the base station signals that are converted downward in frequency in the frequency down converter; a searcher for searching for all of the pilot PNs of the base station signals de¬ modulated in the demodulator; a controller for receiving a result of searching the pilot PNs of the base station signals in the searcher and determining position and size of the pilot PN to insert; a pseudo pilot PN generator for receiving the position and size of the pilot PN determined in the controller and generating the pseudo pilot PN caused by the reception; a modulator for modulating the pseudo pilot PN signal generated in the pseudo pilot PN generator; and a frequency up converter for converting the pseudo pilot PN signal modulated in the modulator upward in frequency according to the control of the controller and outputting the converted pseudo pilot PN signal to be inserted into the base station signals to relay.

[7] 7. The pseudo pilot PN generating apparatus as claimed in claim 6, wherein the controller further calculates and regulates position and size errors of the pseudo pilot PN inserted already after receiving a result of searching the pilot PN of the base station signals including the pseudo pilot PN in the searcher and transfers the result to the pseudo pilot PN generator.

[8] 8. The pseudo pilot PN generating apparatus as claimed in claim 6 or 7, wherein the controller determines a position to which the pseudo pilot PN is inserted in order to insert the pseudo pilot PN into an area that is recognized as the same pilot PN as that of the base station to relay, wherein the pseudo pilot PN generator generates the pseudo pilot PN to be inserted into the insert position determined by the controller.

[9] 9. The pseudo pilot PN generating apparatus as claimed in claim 8, wherein the controller determines the size of the pseudo pilot PN such that the pilot PN of the base station to relay has a higher searching energy than the highest searching energy of the pilot PN of the other base station, wherein the pseudo pilot PN generator generates the pseudo pilot PN determined by the controller.

[10] 10. A method of generating a pseudo pilot PN, comprising the steps of: selecting a frequency assignment (FA) after initializing a search and a pseudo pilot PN generator; allowing the search to search for (detect) all of pilot PNs according to a PN offset value; determining position and size of the pilot PN to be inserted, using a result of searching for (detecting) the pilot PN in the search; and generating a pseudo pilot PN by transferring the determined position and size of the pilot PN to the pseudo pilot PN generator.

[11] 11. The method as claimed in claim 10, further comprising the steps of: allowing the search to search for (detect) pilot PNs of the base station signals including the pseudo pilot PN; calculating the position and size errors of the pseudo pilot PN inserted already using a result of searching for the pilot PN of the base station signals including the pseudo pilot PN in the search; and regulating the calculated position and size errors of the pseudo pilot PN and then relaying from the step of generating the pseudo pilot PN.

[12] 12. The method as claimed in claim 10 or 11, wherein in the step of determining the position to which the pseudo pilot PN is inserted, the position to which the pseudo pilot PN is inserted is determined to insert the pseudo pilot PN into an area that is recognized as the same pilot PN as that of the base station to relay. [13] 13. The method as claimed in claim 12, wherein in the step of determining the size of the pseudo pilot PN, the size of the pseudo pilot PN is determined such that the pilot PN of the base station to relay has a higher searching energy than the highest searching energy of the pilot PN of the other base station. [14] 14. A computer-readable recording medium containing program for executing, on a microprocessor to generate a pseudo pilot PN, functions of: selecting a frequency assignment (FA) after initializing a search and a pseudo pilot PN generator; allowing the search to search for (detect) all of pilot PNs according to a PN offset value; determining position and size of the pilot PN to be inserted, using a result of searching for (detecting) the pilot PN in the search; and generating a pseudo pilot PN by transferring the determined position and size of the pilot PN to the pseudo pilot PN generator. [15] 15. The recording medium as claimed in claim 14, further comprising the functions of: allowing the search to search for (detect) pilot PNs of the base station signals including the pseudo pilot PN; calculating the position and size errors of the pseudo pilot PN inserted already using a result of searching for the pilot PN of the base station signals including the pseudo pilot PN in the search; and regulating the calculated position and size errors of the pseudo pilot PN and then relaying from the step of generating the pseudo pilot PN.