WO2005039071A1

WO2005039071A1 - Apparatus and method for generating the beacon signal of time sharing multi-carrier

Info

Publication number: WO2005039071A1
Application number: PCT/KR2004/002553
Authority: WO
Inventors: Deuk Hyung Ryu
Original assignee: Contela, Inc.
Priority date: 2003-10-06
Filing date: 2004-10-06
Publication date: 2005-04-28
Also published as: KR20050033246A; KR100604455B1

Abstract

There is provided a time sharing multi-carrier beacon signal generating apparatus comprising: a time-division control unit for time-dividing baseband-signal-processed digital communication data into multiple FA frequencies signals and multiple sector signals based on predetermined beacon control information by synchronizing digital clocks with analog clocks and performing signal interpolation for an FA beacon function and a sector beacon function, respectively; a digital-to-analog signal converting unit for converting the time-divided FA and sector beacon digital communication data to FA and sector beacon analog signals, respectively; a frequency modulating the FA and sector beacon RF signals, respectively; and a signal amplification unit for amplifying the FA and sector beacon RF signals to output a predetermined system frequency.

Description

APPARATUS AND METHOD FOR GENERATING THE BEACON SIGNAL OF TIME SHARING MULTI-CARRIER

TECHNICAL FIELD The present invention relates to the apparatus and method for generating the time sharing multi-carrier beacon signal for handoff between base stations having different FA(frequency allocation) s in a CDMA(code division multiple access) wireless communication system. And more particularly, the present invention relates to the apparatus and method for generating the time sharing multi-carrier beacon signal capable of periodically transmitting overhead channels between base stations having different sectors for handoff between base stations having different FAs and multiple sectors in a CDMA wireless communication system.

BACKGROUND ART In CDMA wireless communication system, a handoff scheme is used to allow a communication connection to continue when a mobile unit crosses the boundary between coverage areas of two different base stations. As is known to those skilled in the art, the types of handoff are classified into mainly a soft handoff and a hard handof f . In the present specification, the method and apparatus of performing the hard handoff efficiently is proposed. In order to perform hard handoff between base stations having different FAs in the CDMA communication system, beacon signals including overhead channels (such as pilot, synchronization, and paging channels) are generated. FIG. 1 is a block diagram illustrating a conventional time sharing multi-carrier beacon signal generating apparatus. As shown in FIG. 1, the conventional time sharing multi-carrier beacon signal generating apparatus comprises a baseband signal processing unit 100, a digital-to-analog signal converting unit 110, a CDMA modulating circuit unit 120, a frequency modulating unit 130, a beacon signal processing unit 170, and a power amplification circuit unit 180. The baseband signal processing unit 100 generates the physical layer-processed digital CDMA processing data of CDMA processing data to be transmitted, such as overhead channel, traffic channel, and the like. The digital-to-analog signal converting unit 110 converts the digital CDMA processing data generated by the baseband signal processing unit 100 to analog baseband signal. The CDMA modulating circuit unit 120 modulates the analog baseband signal to generate an intermediate frequency (IF) signal. Alternatively, the baseband signal processing unit 100 may generate digital IF data. In this case, the digital-to-analog signal converting unit 110 converts the digital IF data generated by the baseband signal processing unit 100 to analog IF signal. And the CDMA modulating circuit unit 120 is omitted. The frequency modulating unit 130 modulates the analog IF signal generated by the modulating circuit unit 120 to generate an RF signal. The beacon signal processing unit 170 comprises digital-to-analog signal converting units 140a to 140n, CDMA modulating circuit units 150a to 150n, and periodic beacon signal generating units 160a to lβOn. The digital-to-analog signal converting units 140a to 140n convert the digital CDMA processing data output from the baseband signal processing unit 100 to analog baseband signals corresponding to the number of sectors for beacon function. The CDMA modulating circuit units 150a to 150n modulates the analog baseband signals to analog IF signals for beacon function. The plurality of periodic beacon signal generating units 160a to 160n receives IF signal from the CDMA modulating circuit unit 120 and a plurality of CDMA modulating circuit units 150a to 150n and periodically changes frequency of a PLL (phase locked loop) for modulating the IF signals to RF signals to perform hopping of the beacon signal among RF frequencies. In addition, a power amplification circuit unit 180 amplifies a signal synthesized from the RF signals output from the frequency modulating unit 130 and periodic beacon signal generating units 160a to 160n. The time sharing multi-carrier beacon signal generating apparatus has main signal processing means for providing sound and data. The main signal processing means comprises a baseband signal processing unit 100, a digital-to-analog signal converting unit 110, a CDMA modulating circuit unit 120, and a frequency modulating unit 130. The baseband signal processing unit 100 generates digital CDMA processed data. The digital CDMA processed data is converted to an analog signal by the digital-to-analog signal converting unit 110. The analog signal is modulated into an IF signal having a frequency of, for example, 4.95 MHz by the CDMA modulating circuit unit 120. The IF signal is modulated to an RF signal used for a wireless sound/data service by a frequency modulating unit 130. On the other hand, in the beacon signal processing unit 170 for facilitating communication between the base stations having different FAs, the following operations are performed. The digital-to-analog signal converting units 140a to 140n convert the digital CDMA processing data output from the baseband signal processing unit 100 to analog signals corresponding to the number of sectors for beacon function. The CDMA modulating circuit units 150a to 150n modulates the analog signals to IF signals for beacon function. In response to the IF signals, the periodic beacon signal generating units 160a to 160n generates beacon signal having a frequency of 100 ~ 500 ms . FIG. 2 is a view showing frequency and time domain characteristics of a beacon signal generated by the periodic beacon signal generating unit 160a to 160n. In FIG. 2, traffic FA signal 200 is shown as a main signal in the frequency domain. Beacon signal generating units 160a to 160n receive the IF signals from the CDMA modulating circuit units 120, and 150a to 150n and generate beacon signals 201f to 201n for FA #1 to FA #n, respectively. On the other hand, when the IF signal from the CDMA modulating circuit unit 120 is input to the periodic beacon signal generating units 160a to 160n, in order to compensate for signal loss due to splitting, an power strength of an actually transmitted beacon signal is larger than the power strength 204 of the required beacon signal. In the figure, the power strength of the actually transmitted beacons signal is indicated by 204 + 205. However, in a beacon signal generating apparatus, since unnecessary traffic data as well as overhead channel data is used for the beacon function, much load is burdened on the subsequent power amplification circuit unit. There is a problem in that production cost of the system increases in order to reduce the load. In addition, in the beacon signal processing unit 170, when signals are transmitted from the digital-to- analog signal converting units 140a to 140n thorough the CDMA modulating circuit units 150a to 150n to the periodic beacon signal generating units 160a to 160n, the actually transmitted beacon signal must have the power strength 204 + 205 which is larger than the power strength 204 of the required beacon signal in order to compensate for signal loss generated by the CDMA modulating circuit units 150a to 150n and the periodic beacon signal generating units 160a to 160n. Therefore, there is another problem in that the signal-to-noise (S/N) ration is lowered. Moreover, although the periodic beacon signal generating units 160a to 160n change FAs' by reinitializing the PLL in a software manner, since a time interval 202 of 30 ~ 40 ms is needed to perform the reinitializing process, the beacon signal may be disconnected during the time interval 202. In addition, in a code division multiple access (CDMA) wireless communication system having multiple sectors, there is still another problem in that a large number of digital-to-analog signal converting units, CDMA modulating circuit units, and periodic beacon signal generating units are needed corresponding to the number of sectors.

SUMMARY OF THE INVENTION In order to solve the aforementioned problems, an object of the present invention is to provide a time sharing multi-carrier beacon signal generating apparatus and method capable of perform handoff by simultaneously providing a beacon function for multiple FAs and multiple sectors in a CDMA wireless communication system where multiple sectors are provided to base stations having different FAs or in a CDMA wireless communication system where multiple FA beacon signals are generated for the same sector. Another object of the present invention is to provide a time sharing multi-carrier beacon signal generating apparatus and method by time-dividing sector signals on digital baseband or digital intermediate frequency band capable of minimizing time delay, signal distortion, and forward noise associated with a periodic change of RF carrier frequencies during RF modulation. Still another object of the present invention is to provide a time sharing multi-carrier beacon signal generating apparatus and method capable of simultaneously using FA beacons and sector beacons between non-stereotyped base stations having different FAs and sectors.

In order to achieve the objects, according to an^' aspect of the present invention, there is provided is a time sharing multi-carrier beacon signal generating apparatus comprising: a time-division control unit for time-dividing baseband-signal-processed digital communication data into multiple FA frequencies signals and multiple sector signals based on predetermined beacon control information by synchronizing digital clocks with analog clocks and performing signal interpolation for an FA beacon function and a sector beacon function, respectively; a digital-to-analog signal converting unit for converting the time-divided FA and sector beacon digital communication data to FA and sector beacon analog signals, respectively; a frequency modulating unit for frequency modulating the FA and sector beacon analog signals to FA and sector beacon RF signals, respectively; and a signal amplification unit for amplifying the FA and sector beacon RF signals to output a predetermined system frequency. According to another aspect of the present invention, there is provided a time sharing multi- carrier beacon signal generating method comprising of: a time-division controlling step of time-dividing baseband-signal-processed digital communication data into multiple FA frequencies signals and multiple sector signals based on predetermined beacon control information by synchronizing digital clocks with analog clocks and performing signal interpolation for an FA beacon function and a sector beacon function, respectively; a digital-to-analog signal converting step of converting the time-divided FA and sector beacon digital communication data to FA and sector beacon analog signals, respectively; a frequency modulating step of frequency modulating the FA and sector beacon analog signals to FA and sector beacon RF signals, respectively; and a signal amplifying step of amplifying the FA and sector beacon RF signals to output a predetermined system frequency.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram illustrating a conventional time sharing multi-carrier beacon signal generating apparatus; FIG. 2 is a view showing frequency and time domain characteristics of a beacon signal of FIG. 1; FIG. 3 is a block diagram illustrating a time sharing multi-carrier beacon signal generating apparatus according to the present invention; FIG. 4 is a block diagram illustrating a time- division control unit according to the present invention; FIG. 5 is a view showing time domain characteristics of a beacon signal in a sector beacon according to a preferred embodiment of the present invention; and FIG. 6 is a view showing time and frequency domain characteristics of a beacon signal in an FA beacon according to a preferred embodiment of the present invention .

BEST MODE FOR CARRYING OUT THE INVENTION Now, preferred embodiments of the present invention will be described in detail. FIG. 3 is a block diagram illustrating a time sharing multi-carrier beacon signal generating apparatus according to the present invention As shown in FIG. 3, the time sharing multi-carrier beacon signal generating apparatus comprises a baseband signal processing unit 300, a digital-to-analog signal converting unit 310, a frequency modulating unit 320 (for traffic FA), a beacon signal generating unit 390, an analog switch 370s, and a power amplification circuit unit 380. The baseband signal processing unit 300 generates digital CDMA processing data for CDMA physical layer transmission corresponding to all the data transmitted through overhead channel, traffic channel, and the like. In addition, according to the present invention, the digital CDMA processing data can be generated in a form of a digital IF data signal unlike the prior art. The digital-to-analog signal converting unit 310 converts the digital CDMA processing data or digital intermediate-frequency data output from the baseband signal processing unit 300 to analog baseband data or analog intermediate-frequency data. The frequency modulating unit 320 modulates the analog baseband data signal or analog intermediate- frequency data signal to RF signals. The beacon signal generating unit 390 comprises a time-division control unit 330, digital-to-analog signal converting units 340f and 340s, FA beacon frequency modulation units 350f, and sector beacon frequency modulating units 350s. The time-division control unit 330 performs a time-division process on FA frequency signals and sector signals into multiple FA frequencies signals used for a frequency beacon function and multiple sector signals used for a sector beacon function . Each of the digital-to-analog signal converting units 340f and 340s converts the digital CDMA processing data signal or digital intermediate-frequency data signal output from the baseband signal processing unit 300 to an analog baseband data signal or an analog intermediate-frequency data signal, which are classified into FA beacon and sector beacon types. Each of the frequency modulation units 350f and 350s modulates the analog baseband data signal and an analog intermediate-frequency data signal output from the digital-to-analog signal converting units 340f and 340s to the respective RF signals, which are classified into FA beacon and sector beacon types. Although the ^: digital-to-analog signal converting units 340f and 340s and the frequency modulation units

350f and 350s are classified into FA beacon and sector beacon types, these components may be implemented in a single device without separation. On the other hand, since the beacon signal generating unit 390 is a unitary component for FA beacon and sector beacon, a plurality of the beacon signal generating units 390 may be installed on boards of the respective devices. In the figure, the analog switch 370s performs a

1:N time-division de-multiplexing process to switch the sector beacon RF signals output from the sector beacon frequency modulating unit 350s to the corresponding sectors . The power amplification circuit unit 380 amplifies the RF signals generated by the frequency modulating unit 320 and the frequency modulation units 350f and 350s. Now, detail construction of the time-division control unit 330 will be described with reference to FIG, 4. As shown in FIG. 4, the time-division control unit 330 comprises a time-division multiplexer 401s, a ti e- division processing unit 401f, a system timing control unit 402, a digital synthesizer 403, and a mixer 404. The time-division multiplexer 401s performs a time- division multiplexing process on beacon signals for the multiple sectors s#l to s#n transmitted from the baseband signal processing unit 400 and outputs a time- division multiplexed sector signal to the digital-to- analog signal converting unit 406s. The time-division processing unit 401f performs a time-division process with multiple FA frequencies used for a system and changes signals in a sample rate for signal mixing based on clocks and interpolation factors applied by the system timing control unit 402 in order to synchronize digital process clocks with analog process clocks. Here, it is preferable that the time-division processing unit 401f comprise three FIFO (first in first out) memories in order to cope with a case where the digital process clocks have a higher frequency than analog process clocks (for example, the digital process clock has a frequency of 1.2288 MHz; and the analog process clock has a frequency of 1.25 MHz) . Here, in a case where the same data stored in the two FIFO memories and then time-divided data is changed, the time-division processing unit 401f performs a switching process to switch the FIFO memories every time when the frequency changes, so that under-run and over-run resulting from difference clocks can be removed. The system timing control unit 402 controls system timings of the time-division multiplexer 401s and the time-division processing unit 401f with respective system timing control signals 402f and 402s generated based on control information transmitted from an external CPU interface. In addition, the system timing control unit 402 controls system timings of the digital- to-analog signal converting unit 340f and the analog switch 370 with respective system timing control signals 360f and 360s. Here, the control information transmitted from the CPU interface 407 includes beacon control information used for the system (that is, number of FAs, number of sectors, time-division timings, period, duration, and signal interpolation factors) and mixing period information . The digital synthesizer 403 generates digital sine/cosine signals based on the control information such as timing information transmitted from the system timing control unit 402. In addition, the digital synthesizer 403 generates a clock signal in proportion to the sampling rate of the time-division processing unit 401f . The mixer 404 multiplies a signal output from the time-division processing unit 401f with a signal output from the system timing control unit 402 to output the multiplied signal to the digital-to-analog signal converting unit 406f. FIG. 6 is a view showing time domain characteristic of a beacon signal in a sector beacon according to a preferred embodiment of the present invention. As shown in FIG. 5, for the purpose of traffic FA communication, the analog RF signal 500 processed by the baseband signal processing unit 300, the digital-to-analog signal converting unit 310, and the frequency modulating unit 320 is generated in a frequency band of 1.25 MHz band. In the time domains (the x-axis), a real traffic FA comprises the analog RF signal 500 and the traffic FA RF signal 504. In addition, in the figure, for the beacon transmission, analog RF signals 501sa to 501sn which are processed by the time-division control unit 330, the digital-to-analog signal converting unit 340s, and the frequency modulating unit 350s are generated at the respective sectors sa to sn at the respective given times. The analog RF signals 501sa to 501sn are generated to change sectors for a delay time 502s of 0 ns . FIG. 6 is a view showing time and frequency domain characteristics of a beacon signal in an FA beacon according to a preferred embodiment of the present invention. As shown in FIG. 6, for the traffic FA communication, the analog RF signal 600f processed by the baseband signal processing unit 300, the digital-to- analog signal converting unit 310, and the frequency modulating unit 320 is generated in a frequency band of 1.25 MHz. In the time and frequency domains (the x- axis), a real traffic FA comprises the analog RF signal 600f and the traffic FA RF signal 604f. In addition, in the figure, for the beacon transmission, analog RF signals 601fa to 601fn processed by the time-division control unit 330, the digital-to- analog signal converting unit 340f, and the frequency modulating unit 350f are generated at the respective frequencies fa to fn at the respective given times. The analog RF signals 601sa to 601sn are generated to change sectors for a delay time 602f of 0 ns . Now, operations of the time sharing multi-carrier beacon signal generating apparatus according to the present invention will be described with reference to the accompanying drawings. First, operations of the present invention will be described in point of sector beacon characteristics The digital-to-analog signal converting unit 310 converts the digital CDMA processing data or digital intermediate-frequency data output from the baseband signal processing unit 300 to analog baseband data or analog IF data. The frequency modulating unit 320 modulates the analog baseband data signal or analog IF data signal to RF signals to provide sound and data in a wireless communication. The beacon signal generating unit 390 generates beacon signals for a good communication between the base station having different FAs and multiple sectors. The time-division multiplexer 401s of the time-division control unit 330 performs a time-division multiplexing process on beacon signals for the multiple sectors s#l to S#n transmitted from the baseband signal processing unit 400 to generate sector signals having a duration of 100 to 500 ms with the same frequency for the sector S#l to S#n at the timings which the system timing control unit 402 controls based on sector beacon control information (that is, number of sectors, time-division timings, period, and duration) transmitted from the CPU interface 407. More specifically, in a case where the time- division multiplexer 401s of the beacon signal generating unit 390 performs a beacon function for 4 FAs at a base station having 3 sectors, the time-division multiplexer 401s generates sector signals based on 3 sector beacon signals transmitted from the baseband signal processing unit 300 at the timings which the system timing control unit 402 controls based on time- division timing information transmitted from the CPU interface 407. Next, the digital-to-analog signal converting unit 340s converts the time-divided sector signals (digital signals) to analog sector signals. The frequency modulating unit 350s modulates the analog sector signals to RF sector beacon signals, so that the beacon function can be performed for the 3 sectors with the same frequency. The RF sector beacon signal generated by the frequency modulating unit 350s is output to the power amplification circuit unit 380 via the analog switches 370s. The power amplification circuit unit 380 amplifies the RF sector beacon signal to matching to the corresponding sector. If 4 -sets of the aforementioned components for forming sector beacons are constructed, a time-division sector beacon device with a 3-sector 4-FA beacon function can be implemented. On the other hand, as shown in FIG. 5, the time- division control unit 330 can construct multiple sectors for a delay time 502s of 0 ns, so that it is possible to remove service failure time involved in PLL initialization unlike the prior art. In addition, it is possible to support base stations having multiple sectors with a single sector beacon path. In addition, as shown in FIG. 5, since only beacon signals with necessary beacon power are transmitted by the sector beacon function according to the present invention, it is possible to minimize load of the power amplification circuit unit 180 unlike the prior art. Now, operations and FA beacon characteristics of the time sharing multi-carrier beacon signal generating apparatus according to the present invention will be described with reference to the accompanying drawings. The digital-to-analog signal converting unit 310 converts the digital CDMA processing data or digital intermediate-frequency data output from the baseband signal processing unit 300 to analog baseband data or analog IF data. The frequency modulating unit 320 modulates the analog baseband data signal or analog IF data signal to RF signals to provide sound and data in a wireless communication. The beacon signal generating unit 390 generates beacon signals for a good communication between the base station having different FAs. In a first example of performing a beacon function for 4 FAs, the beacon control information provide by the CPU interface 407 is assumed to be as follows. Number of FAs: 4, Duration per FA: 200 ms , tl = 0ms 4- 200ms x 4a, t2 = 200ms + 200ms x 4a, t3 = 400ms + 200ms x 4a, t4 = 600ms + 200ms x 4a (here, a is a integer) CDMA data: chip x 1 (1 oversample) , 1.2288 MHz Digital Synthesizer Clock: 1.2288 MHz x n (here, n = 2 x integer) , and FIFO Clock: 1.2288 MHz Beacon Bandwidth: 5 MHz In addition, it is assumed in the first example that sine (0, 1, 0, -1) and cosine (1, 0, -1, 0) signals having 4 samples are generated by the digital synthesizer 403. Firstly, the system timing control unit 402 receives the aforementioned beacon control information such as number of sectors, time-division timings, period, duration, and signal interpolation factor from the CPU interface 407. In the step tl, the system timing control unit 402 set the signal interpolation factor of the time-division processing unit 401f to "0", so that the time-division processing unit 401f can be bypassed. In addition, the system timing control unit 402 allows the digital synthesizer 403 and the mixer to be bypassed. The digital-to-analog signal converting unit 340f is provided with chip xl clock (1.25 MHz). Next, in the step t2, the system timing control unit 402 set the' signal interpolation factor of the time-division processing unit 401f to "4", so that 4 samples can be generated. In addition, the system timing control unit 402 allows the digital synthesizer 403 to generate the sine and cosine signals having a frequency of 1.25 MHz. As a result, the bits of 0, 4, 0, and -4 are generated in a rate of 1.25 x 4 MHz. The system timing control unit 402 commands the mixer 404 to multiply the data output from the time-division processing unit 401f with the data output from the digital synthesizer 403. The digital-to-analo^'g signal converting unit 340f is provided with a clock signal of 5 MHz. Next, in the step t3, the system timing control unit 402 set the signal interpolation factor of the time-division processing unit 401f to "8", so that 8 samples can be generated. In addition, the system timing control unit 402 allows the digital synthesizer 403 to generate the sine and cosine signals having a frequency of 2.5 MHz. As a result, the bits of 0, 4, 0, and -4 are generated in a rate of 2.5 x 4 MHz. The system timing control unit 402 commands the mixer 404 to multiply the data output from the time-division processing unit 401f with the data output from the digital synthesizer 403. The digital-to-analog signal converting unit 340f is provided with a clock signal of 10 MHz. Next, in the step t4, the system timing control unit 402 set the signal interpolation factor of the time-division processing unit 401f to "12", so that 12 samples can be generated. In addition, the system timing control unit 402 allows the digital synthesizer 403 to generate the sine and cosine signals having a frequency of 3.75 MHz. As a result, the bits of 0, 4, 0, and -4 are generated in a rate of 3.75 x 4 MHz. The system timing control unit 402 commands the mixer 404 to multiply the data output from the time-division processing unit 401f with the data output from the digital synthesizer 403. The digital-to-analog signal converting unit 340f is provided with a clock signal of 15 MHz. The time-division control unit 330 repeats the steps tl to t4 in units of 200 ms to generate beacon signal by performing beacon functions on the digital baseband and IF signals. The beacon signal is converted to an analog signal by the digital-to-analog signal converting unit 340f. In the step tl, the analog signal is modulated with a frequency of 870.265 MHz by the frequency modulating unit 350f to generate a signal having a central frequency of 870.265 MHz and a bandwidth of 1.25 MHz. As a result, the beacon signal performs hopping among frequencies of 870.265, 871.515 (870.265 + 1.25), 872.765, and 874.265 MHz in the steps tl to t4, respectively. As a second example, it is assumed that sine (1, 2, 3, 4, 3, 2, 1, 0, -1, -2, -3, -4, -3, -2, -1) and cosine (4, 3, 2, 1, 0, -1, -2, -3, -4, -3, -2, -1, 0, 1, 2, 3) signals having a maximum of 16 samples are generated by the digital synthesizer 403. The beacon control information transmitted from the CPU interface 407 in the second example for the 16 samples is the same as that of the first example for the 4 samples. In response to the beacon control information transmitted from the CPU interface 407, the system timing control unit 402 set the signal interpolation factor to "16" for the time-division processing unit 401f and provides a 20-MHz clock to the digital-to- analog signal converting unit 340f. In addition, the digital synthesizer 403 is adjusted with the number of frequency samples. That is, in a step tl, the system timing control unit 402 performs a bypass control on the digital synthesizer 403 and the mixer 404. In a step t2, under the control of the system timing control unit 402, sine and cosine signals (that is, 0, 1, 2, 3, 4, 3, 2, 1, 0, -1, -2, -3, -4, -3, -2, -1) for 16 samples are generated with a frequency of 1.25 MHz by the digital synthesizer 403; and the mixer 404 multiplies the data output from the time-division processing unit 401f with the data output form the digital synthesizer 403. In addition, in a step t3, under the control of the system timing control unit 402, sine and cosine signals (that is, 0, 2, 4, 2, 0, -2, -4, -2) for 8 samples are generated with a frequency of 2.5 MHz by the digital synthesizer 403; and the mixer 404 multiplies the data output from the time-division processing unit 401f with the data output form the digital synthesizer 403. Next, in a step t4, under the control of the system timing control unit 402, sine and cosine signals (that is, 0, 4, 0, -4) for 4 samples are generated with a frequency of 5 MHz by the digital synthesizer 403; and the mixer 404 multiplies the data output from the time- division processing unit 401f with the data output form the digital synthesizer 403. The time-division control unit 330 repeats the steps tl to t4 in units of 200 ms to generate beacon signal by performing beacon functions on the digital baseband and IF signals. The beacon signal is converted to an analog signal by the digital-to-analog signal converting unit 340f. In the step tl, the analog signal is modulated with a frequency of 870.265 MHz by the frequency modulating unit 350f to generate a signal having a central frequency of 870.265 MHz and a bandwidth of 1.25 MHz. As a result, the beacon signal performs hopping among frequencies of 870.265, 871.515 (870.265 + 1.25), 872.765, and 874.265 MHz in the steps tl to t4, respectively. Here, the frequency modulating unit 350f modulates the signal with different frequency suitable for the system. The FIFOs of the time-division processing unit 401f can be selectively provided in order to compensate for synchronization mismatching of signal mixing due to different clocks of digital and analog domains. The data output from the baseband signal processing unit 300 is stored in the two FIFO memories. As a result, under-run and over-run resulting from difference clocks can be removed. In addition, the frequency error between the digital and analog signal due to different processing frequencies are prevented in advance. Therefore, it is possible to obtain a high quality of CDMA data. Referring to FIG. 6, in the frequency domain, the traffic FA 600f is generated as a main signal; and n FA beacon signals 601fa to 601fn for n FAs FA#1 to FA#n are generated. According to the present invention, since only the beacon signals with necessary beacon power 603 are transmitted by the sector beacon function according to the present invention, it is possible to minimize load of the power amplification circuit unit 180 unlike the prior art . As described above, in the time sharing multi- carrier beacon signal generating apparatus according to the present invention, the beacon signal may be used to perform FA and sector beacon functions on the digital communication data in accordance with one of a CDMA scheme, a GSM scheme, and a Wireless LAN data communication scheme. While the present invention has been particularly shown and described with reference to exemplary embodiments 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 spirit and scope of the present invention as defined by the appended claims.

INDUSTRIAL APPLICABILITY

According to the present invention, in a multi- carrier/multi-sector environment where base stations have different FAs and sectors, FA and sector beacon functions are provided to all types of system, so that it is possible to perform the beacon functions by a single system board without change of hardware. In addition, since only beacon signals with necessary beacon power are transmitted by the beacon functions, it is possible to minimize load of a power amplification circuit unit. In addition, it is possible to prevent loss of signal resulting from signal splitting in analog transmission region and IF signal modulating. In addition, it is possible to reduce cost of system and transmit a high quality of signal.

Claims

CLAIMS 1. A time sharing multi-carrier beacon signal generating apparatus comprising: a time-division control unit for time-dividing baseband-signal-processed digital communication data into multiple FA (frequency allocation) frequency signals and multiple sector signals based on predetermined beacon control information by synchronizing digital clocks with analog clocks and performing signal interpolation for an FA beacon function and a sector beacon function, respectively; a digital-to-analog signal converting unit for converting the time-divided FA and sector beacon digital communication data to FA and sector beacon analog signals, respectively; a frequency modulating unit for frequency modulating the FA and sector beacon analog signals to FA and sector beacon RF signals, respectively; and a signal amplification unit for amplifying the FA and sector beacon RF signals to output a predetermined system frequency.

2. The time sharing multi-carrier beacon signal generating apparatus according to claim 1, wherein the time-division control unit comprises: a time-division multiplexer for time-division- multiplexing the multiple sector signal; a time-division processing unit for performing time-division process with multiple FA frequencies by converting the digital communication data to a predetermined number of sample data; a digital synthesizer for generating digital sine/cosine signals based on the predetermined beacon control information; a multiplication unit for multiplying a signal output from the time-division processing unit with a signal output from the digital synthesizer to generate a multiple-frequency beacon signal; and a system timing control unit for controlling timings of the time-division process on the sector signals in the time-division multiplexer and the time- division process of the FA frequency signals in the time-division processing unit, digital synthesizer, and multiplication unit based on the predetermined beacon control information.

3. The time sharing multi-carrier beacon signal generating apparatus according to claim 2, wherein the predetermined beacon control information includes at least one of number of FAs, time-division timings, period, duration, and signal interpolation factor.

4. The time sharing multi-carrier beacon signal generating apparatus according to claim 3, further comprising a CPU interface for externally setting the predetermined beacon control information.

5. The time sharing multi-carrier beacon signal generating apparatus according to claim 1, wherein the respective numbers of the time-division control units, the digital-to-analog signal converting units, and the frequency modulating units are determined based on the numbers of the required FA frequency and the sectors.

6. The time sharing multi-carrier beacon signal generating apparatus according to one of claims 1 to 5, wherein the beacon signal is used to perform FA and sector beacon functions on the digital communication data in accordance with one of a CDMA scheme, a GSM scheme, and a Wireless LAN data communication scheme.

7. The time sharing multi-carrier beacon signal generating apparatus according to claim 1, further comprising an analog switch for performing a 1:N time- division de-multiplexing process to switch the sector beacon RF signals output from the frequency modulating unit to the corresponding sectors.

8. A time sharing multi-carrier beacon signal generating method comprising of: a time-division controlling step of time-dividing baseband-signal-processed digital communication data into multiple FA frequencies signals and multiple sector signals based on predetermined beacon control information by synchronizing digital clocks with analog clocks and performing signal interpolation for an FA beacon function and a sector beacon function, respectively; a digital-to-analog signal converting step of converting the time-divided FA and sector beacon digital communication data to FA and sector beacon analog signals, respectively; a frequency modulating step of frequency modulating the FA and sector beacon analog signals to FA and sector beacon RF signals, respectively; and a signal amplifying step of amplifying the FA and sector beacon RF signals to output a predetermined system frequency.

9. The time sharing multi-carrier beacon signal generating method according to claim 8, wherein the time-division controlling step comprises: a time-division multiplexing step of time-division- multiplexing the multiple sector signals; a time-division processing step of performing time-, division process with multiple FA frequencies by converting the digital communication data to a predetermined number of sample data; a digital synthesizing step of generating digital sine/cosine signals based on the predetermined beacon control information; and a multiplying step of multiplying a signal generated in the time-division processing step with a signal generated in the digital synthesizing step to generate a multiple-frequency beacon signal.

10. The time sharing multi-carrier beacon signal generating method according to claim 9, wherein the predetermined beacon control information includes at least one of number of FA frequency, time-division timings, period, duration, and signal interpolation^' factor.

11. The time sharing multi-carrier beacon signal generating method according to claim 8, wherein the predetermined beacon control information is set by an external CPU interface.

12. The time sharing multi-carrier beacon signal generating method according to one of claims 8 to 11, wherein the beacon signal is used to perform FA and sector beacon functions on the digital communication data in accordance with one of a CDMA scheme, a GSM scheme, and a Wireless LAN data communication scheme.

13. The time sharing multi-carrier beacon signal generating method according to claim 8, further comprising an analog switching step of performing a 1:N time-division de-multiplexing process to switch the sector beacon RF signals to the corresponding sectors.