KR20080097838A - Apparatus and method for transmitting beacons in wireless communication system based cognitive radio - Google Patents

Abstract

An apparatus and a method for transmitting beacons in a wireless communication system based on cognitive radio receive a beacon signal flexibly without a demodulation process in a receiving terminal by combining a control channel sequence and a DQPSK modulation symbol. A sequence generating unit generates a control sequence with orthogonality in a quaternary domain and a binary domain. A transmitting unit transmits the generated control sequence. The control sequence is one of the RTS(Request To Send) or the ACK(ACKnowledgment)/NACK(Negative-ACKnowledgment).

Description

Beacon transmission device and method in wireless communication system based on wireless recognition {APPARATUS AND METHOD FOR TRANSMITTING BEACONS IN WIRELESS COMMUNICATION SYSTEM BASED COGNITIVE RADIO}

The present invention relates to a beacon transmission apparatus and method in a wireless communication system, and more particularly, to an apparatus and method for flexibly transmitting a beacon signal in a wireless communication system based on wireless recognition.

Recently, the shortage of frequency resources due to the rapid increase in the market of wireless communication systems has emerged seriously, and as a solution for this, research on wireless cognitive (hereinafter referred to as "CR") technology is being actively conducted. The CR technology is fundamentally based on a new concept of frequency management policy of open frequency allocation, which is an advanced resource sharing concept in the fixed frequency allocation of frequency assignment, which is a national propagation policy. Currently, most countries in the world are considering solving the frequency shortage problem by changing the concept from fixed frequency allocation to open frequency allocation and are trying to develop a frequency sharing technology such as CR that embodies this concept.

The basic concept of the CR technology is that a new user (CR user) added while guaranteeing service in a licensed frequency band of an incumbent user periodically or aperiodically to perform a predetermined communication purpose. And repeating the setting-moving-transmission-release of the communication channel actively by measuring the unexpected interference.

Most importantly in the CR technology, the CR user should not detect and interfere with the signal of the user. Accordingly, there is a need for a fast and reliable radio control channel, which can be made with the use of radio beacons. For example, in order for a CR base station and a CR user to recognize the appearance of a low power user (eg, a wireless microphone), a beacon signal must be broadcast through a control channel at high power to inform the presence of the low power user. . Here, what is generally required for the beacon is to avoid interference between the user and the CR user. It must be resistant to disturbances in the radio channel, beacon periods must be short, and used at low power. Currently, a general example of the beacon has been developed in the Institute of Electrical and Electronics Engineers (IEEE) 802.22.1 standard.

In the IEEE 802.22.1 standard, a beacon signal is processed by differential quadrature phase shift keying (hereinafter referred to as "DQPSK") using a complex spreading sequence. Within the IEEE 802.22.1 standard, the control channel is still based on a binary decision approach. The receiver works with an inflexible detection structure that cannot be flexibly demodulated at the receiving end.

1 illustrates an example of a request to send (RTS) and an acknowledgment / negative-acknowledgment period (ANP) slot structure according to the prior art.

Referring to FIG. 1, a time slot is divided into a turn time, an RTS burst, a turn time, an ANP burst, and a turn time. In addition, the time slot is divided into symbol times (segments), and one modulation symbol is transmitted through one symbol time. One time slot consists of a total of 32 symbols, the RTS burst has six symbols, the ANP burst has three symbols, and each transition time has five symbols.

Here, in the DQPSK region, the RTS burst and the ANP burst are not orthogonal and are not the same length. Therefore, since the RTS burst and the ANP burst are detected in the binary region, the RTS burst and the ANP burst cannot be detected flexibly at the receiving end. That is, DQPSK is required at the receiving end.

Accordingly, there is a need for an apparatus and method for flexibly transmitting a beacon signal by combining a control channel sequence and a DQPSK modulation symbol in a wireless communication system based on wireless recognition.

Accordingly, an object of the present invention is to provide a beacon transmission apparatus and method in a wireless communication system based on wireless recognition.

It is another object of the present invention to provide an apparatus and method for transmitting a beacon signal in a flexible manner directly without a demodulation process in a wireless communication system based on wireless recognition.

It is still another object of the present invention to provide an apparatus and method for transmitting a beacon signal by combining a control channel sequence and differential quadrature phase shift keying (DQPSK) in a wireless communication system based on wireless recognition. have.

According to a first aspect of the present invention for achieving the above objects, in a beacon transmission apparatus in a wireless communication system based on wireless recognition, orthogonality in a binary domain and a quaternary domain And a transmitter for transmitting the generated control sequence and a transmitter for transmitting the generated control sequence.

According to a second aspect of the present invention for achieving the above object, in a beacon receiving apparatus in a wireless communication system based on wireless recognition, a matched filter unit for detecting a signal and despreading the detected signal And a decoupling unit for outputting a modulation symbol, a correlator for correlating the despread modulation symbol with a control sequence, and a determining unit for determining a corresponding control sequence from the correlation result value.

According to a third aspect of the present invention for achieving the above object, in a beacon receiving apparatus in a wireless communication system based on wireless recognition, a matching filter unit for detecting a signal and despreading the detected signal And a demodulator configured to demodulate the despread modulation symbol, and a comparator configured to determine a corresponding control sequence by comparing the demodulated output bit with a control sequence.

According to a fourth aspect of the present invention for achieving the above objects, in a beacon transmission method in a wireless communication system based on wireless recognition, orthogonality in a binary domain and a quaternary domain And generating a control sequence having the control sequence and transmitting the generated control sequence.

According to a fifth aspect of the present invention for achieving the above objects, in a beacon receiving method in a wireless communication system based on wireless recognition, a process of detecting a signal, despreading the detected signal to modulate a modulation symbol And performing a correlation between the despread modulation symbol and a control sequence and determining a corresponding control sequence from the correlation result.

According to a sixth aspect of the present invention for achieving the above objects, in a beacon receiving apparatus in a wireless communication system based on a wireless recognition, the process of detecting a signal, despreading the detected signal to modulate the modulation symbol And a process of demodulating the despread modulation symbol, and determining a corresponding control sequence by comparing the demodulated output bit with a control sequence.

According to a seventh aspect of the present invention for achieving the above object, in a wireless communication system based on a radio beacon (beacon) transmission, the first transmission of data, RTS (Request To Send) during transmission And a second beacon device transmitting an ACK (ACKnowledgment) or a NACK (Negative-ACKnowledgment) after the beacon device and the RTS are transmitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of related well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, an apparatus and method for flexibly transmitting a beacon signal in a wireless communication system based on Cognitive Radio (hereinafter referred to as "CR") will be described.

2 illustrates an example of a beacon operation for protecting terminals in a licensed frequency band in a wireless communication system based on wireless recognition according to an embodiment of the present invention.

Referring to FIG. 2, the CR base station 212 communicates with the CR terminals 204 to 210 by reusing the licensed frequency within the cell radius 202. In this case, the CR base station 212 and the CR terminal (204 ~ 210) when there is a terminal (hereinafter referred to as a licensed terminal) using a licensed frequency band in the vicinity of the licensed terminal (for example, wireless microphones 213, 214 ), TV receivers, etc.) shall not interfere.

When low power grant terminals such as wireless microphones (MCs) 213 and 214 do not exist near the CR base station 212 (cell radiuses 200 and 224 of the wireless microphones 213 and 214 are CR base stations 212, respectively). And when not included in the reception range of the CR terminals 204 to 210) In fact, it is difficult for the CR base station 212 to detect the appearance of all grant terminals 213 and 214 within a cell radius. Therefore, it should be detected by the search by the CR terminals 204 to 210 distributed in the cell. However, the CR terminals 204 to 210 do not exist in the vicinity of the low power terminal such as the wireless microphones 213 and 214, and the wireless microphones 213 and 214 use the same spectrum as the CR base station 212. In this case, since the CR base station 212 and the CR terminals 204 to 210 do not recognize the existence of the wireless microphones 213 and 214, the CR system is maintained without changing the communication channel. Therefore, the wireless microphones 213 and 214 can no longer communicate on the corresponding channel due to the interference of the CR system.

In order for the CR base station 212 and the CR terminals 204 to 210 to recognize the appearance of the low power wireless microphones 213 and 214, a primary protecting device (PPD) 216 and a secondary protecting device (SPD) 218 are provided. Broadcast a beacon signal at high power to indicate the presence of the wireless microphones (213, 214). Here, the PPD 216 and the SPD 218 are beacon devices that issue beacon signals, respectively, within the allowable ranges 220 and 222. Accordingly, the PPD 216 and the SPD 218 transmit a beacon signal so that the CR base station 212 or the CR terminals 204-210 can detect the existence of the wireless microphones 213 and 214. do.

In general, the PPD 216 and the SPD 218 allow communication according to the mutual communication procedure in the IEEE 802.22.1 standard. A communication procedure between the PPD 216 and the SPD 218 will be described with reference to FIG. 9.

First, when transmitting data to the PPD 216 in step 904, the SPD 218 transmits a Request To Send (RTS) burst to indicate that there is data to transmit.

After that, when the PPD 216 receives the RTS burst from the SPD 218 in step 906, the PPD 216 transmits an ACK / NACK burst during the Acknowledgment / Negative-acknowledgment Period (ANP) to determine whether to allow the data transmission of the SPD 218. Inform.

In this case, when the SPD 218 receives the ACK burst in step 912, the SPD 902 transmits a beacon signal. If the NACK burst is transmitted, the PPD 216 transmits a beacon signal in step 910. do. Hereinafter, the RTS and ANP slot structures will be described with reference to FIG. 3.

The algorithm of the present invention is then terminated.

3 illustrates an RTS and ANP slot structure according to an embodiment of the present invention.

Referring to FIG. 3, a time slot is divided into a turn time (Turnaround Time), an RTS burst, a turn time, an ANP burst, and a turn time. In addition, the time slot is divided into symbol times (segments), and one modulation symbol is transmitted through one symbol time. One time slot consists of a total of 32 symbols, the RTS burst has 4 symbols, the ANP burst has 4 symbols, and each transition time has 8 symbols. In this case, the RTS burst size, the ANP burst size, and the switching time size may be changed according to an implementation. However, the RTS burst size and the ANP burst size should be designed to maintain orthogonality with each other.

If the PPD 216 transmits the RTS burst periods r0, r1, r2, and r3, the SPD 218 receives the ANP burst periods a0, a1, a2, and a3. On the contrary, when the SPD 218 transmits the RTS burst periods r4, r5, r6, and r7, the PPD 216 receives the ANP burst periods a4, a4, a4, and a4.

The RTS and ACK / NACK bursts are made up of two sequence sets of four DQPSK modulation symbols. These sequences (RTS and ACK / NACK) are selected in consideration of their good autocorrelation and cross-correlation characteristics. They are also selected by optimizing the codewords simultaneously in the binary and quaternary domains. The receiver can flexibly choose ACK and NACK.

The RTS and the ANP codewords (ACK / NACK) are surrounded by a period of turnaround time. Therefore, the DQPSK encoder and decoder must be initialized at the beginning of each codeword. The sequence of DQPSK symbols associated with the binary codeword is therefore crucial. The codeword is designed using this property.

In the present invention, the RTS codeword, the ACK, and the NACK codeword are defined as shown in Table 1, Table 2, and Table 3, respectively. Table 1 below shows an RTS codeword format.

(DQPSK) Symbol number 0 One 2 2 Bit i One 0 One 0 Bit Q One 0 One 0 DQPSK symbol -1-j -1-j 1 + j 1 + j

Table 2 below shows the ACK codeword format.

(DQPSK) Symbol number 0 One 2 2 Bit i 0 One 0 One Bit Q 0 One 0 One DQPSK symbol 1 + j -1-j -1-j 1 + j

Table 3 below shows a NACK codeword format.

(DQPSK) Symbol number 0 One 2 2 Bit i One 0 One 0 Bit Q One 0 One 0 DQPSK symbol -1-j -1-j -1 + j 1 + j

That is, the sequences {1 + j, -1-j, -1-j, 1 + j} and {-1-j, -1-j, 1 + j, 1 + j} are considered. Where j is to be. The two sequences are orthogonal to each other and they also have only two levels of signals 1 + j, -1-j. The first codeword (-1-j, -1-j, 1 + j, 1 + j) is selected as the ACK codeword and the second codeword (1 + j, -1-j, -1-j, 1 + j) selects the NACK codeword and the RTS codeword.

The ACK and the NACK codewords are selected with two different codewords to be separated by the maximum distance, so that the SPD does not confuse the PPD's response with the RTS. After receiving the ACK, the SPD may begin transmitting. On the other hand, if the SPD receives a NACK, it does not allow the transmission to start. When the RTS codeword is selected as the NACK codeword, it may be received by another SPD at an incorrect timing. Again, due to orthogonality, other SPDs do not confuse NACK with ACK. Since the NACK codeword has been transmitted by the PPD, there is no chance of being received by the PPD and confused with the RTS.

The length of the turnaround times is increased from 8 symbols to 8 symbols in the prior art. However, this is independent of the present invention and other lengths of transition periods are provided without change in the proposed sequences and methods.

4 illustrates a beacon transmitter in a wireless communication system based on wireless recognition according to an embodiment of the present invention.

Referring to FIG. 4, the beacon transmitter includes a sequence generator 400, a series-parallel converter 402, a modulator 404, a diffuser 406, and a pulse shape unit 408.

The sequence generator 400 generates a sequence defined in <Table 1>, <Table 2>, and <Table 3> and outputs the sequence to the serial-to-parallel converter 402. For example, when it is necessary to generate the RTS and NACK sequences, the sequence generator 400 generates the 11001100 sequence, and when generating the ACK sequence, the sequence generator 400 generates the 00110011 sequence. Here, the RTS and NACK sequence and the ACK sequence have orthogonality when they have the same size. The 11001100 sequence and the 00110011 sequence are just examples, and codes having orthogonality between codes may be various in some cases, and the present invention may also be applied to other orthogonal codes.

The serial-to-parallel converter 402 receives a serial sequence generated from the sequence generator 400, converts the serial sequence into a parallel sequence, and outputs the serial sequence to the modulator 404.

The modulator 404 receives the parallel sequence from the serial-to-parallel converter 402 and modulates the parallel sequence to the spreader 406. For example, when using DQPSK modulation, the DQPSK symbols shown in Table 1, Table 2, and Table 3 are output. The DQPSK modulation is a phase modulation that performs a logical sum of binary codes on the transmitting side and shifts four kinds of phases to different propagation, and is used in a direct sequence spread spectrum (DSSS) scheme. In some embodiments, the modulator 404 may use other modulation schemes (eg, QPSK, BPSK, QAM modulation).

The spreader 406 receives a modulation symbol from the modulator 404, multiplies the spread symbol, and spreads a modulation symbol (output at chips), and outputs the modulated symbol to the pulse shape unit 408. Here, if one signal symbol is spread in a predetermined sequence, a spread spectrum signal with a lower power density per frequency can be obtained. The same spreading sequence can be used at the receiver to reproduce the original signal. Modulation efficiency is good, signal synchronization is fast, and lower power density results in less in-band interference.

The pulse shaper 408 performs a pulse shape to remove the inter-symbol interference of the signal with respect to the spreading sequence output at the chip rate from the spreader 406. The spreading sequences passing through the pulse shape unit 408 are transmitted through an antenna by dividing the I (Inphase) / Q (Quadrature) channel and multiplying each of the corresponding carriers (not shown in FIG. 4).

5 illustrates a beacon receiver in a wireless communication system based on wireless recognition according to an embodiment of the present invention.

Referring to FIG. 5, the beacon receiver includes a matched filter unit 500, a despreader 502, a first correlator 504, a second correlator 506, and a determiner 508. do.

The matched filter unit 500 matches a signal received from an antenna (not shown) and outputs an RTS and an ACK / NACK signal to the despreader 502. In other words, the matched filter unit 500 detects extremely weak specific signals (RTS and ACK / NACK signals) among the noise-rich signals.

The despreader 502 despreads the signal from the matched filter unit 500 using a spreading sequence of the transmitter (the beacon transmitter of FIG. 4). The despreading outputs a signal having a chip rate and a corresponding modulation symbol (eg, a DQPSK modulation symbol).

The first correlator 504 receives a modulation symbol from the despreader 502 and multiplies with a predetermined ACK sequence to perform correlation to provide a result to the determiner 508.

The second correlator 506 receives the modulation symbol from the despreader 502 like the first correlator 504 and multiplies with a predetermined NACK sequence to perform correlation to determine the result. Provided at 508. In some implementations, the functions of the first correlator 504 and the second correlator 506 may be changed.

The determination unit 508 determines whether the signal received from the antenna is an ACK signal or a NACK signal by using correlation results from the first correlator 504 and the second correlator 506, respectively.

6 illustrates a beacon receiver in a wireless communication system based on wireless recognition according to another embodiment of the present invention.

Referring to FIG. 6, the beacon receiver includes a matched filter unit 600, a despreader 602, a modulator 604, and a comparator 606.

The matched filter unit 600 matches signals received from an antenna (not shown) and outputs an RTS and an ACK / NACK signal to the despreader 502. That is, the matched filter unit 600 detects extremely weak specific signals (RTS and ACK / NACK signals) among the noise-rich signals.

The despreader 602 despreads the signal from the matched filter unit 600 using a spreading sequence of the transmitter (the beacon transmitter of FIG. 4). The despreading outputs a signal having a chip rate and a corresponding modulation symbol (eg, a DQPSK modulation symbol).

The demodulator 604 demodulates a corresponding modulation symbol from the despreader 602 and outputs a sequence (bit).

The comparator 606 receives the sequence from the demodulator 604 and compares a predetermined ACK sequence and a NACK sequence to determine whether the signal received from the antenna is an ACK sequence or a NACK sequence.

As described above, by setting the RTS or NACK sequence and the ACK sequence to the same size and having orthogonality between the two sequences, the receiver can flexibly determine the RTS or NACK sequence and the ACK sequence. That is, the receiver can determine the RTS or NACK sequence and the ACK sequence without the demodulator (FIG. 5).

7 illustrates a beacon transmitter operation in a wireless communication system based on wireless recognition according to an embodiment of the present invention.

Referring to FIG. 7, the transmitter determines an RTS or ANP burst structure in step 700. For example, it is designed to have the same RTS burst or ANP burst size.

The transmitter generates a sequence for an RTS or ANP burst in step 702. At this time, the sequence for the RTS or ANP burst is generated to have orthogonality to each other.

The transmitter transmits the corresponding sequence (RTS, ACK / NACK) generated in step 704 in a direct sequence spread spectrum (DSSS) scheme.

The algorithm of the present invention is then terminated.

8 illustrates a beacon receiver operation in a wireless communication system based on wireless recognition according to an embodiment of the present invention.

Referring to FIG. 8, the receiver receives an RTS or ACK / NACK through an antenna in step 800.

In step 802, the receiver demodulates a signal according to a corresponding RTS or ACK / NACK structure. In this case, the receiver may directly determine the RTS or ACK / NACK sequence without demodulation using the correlation of the signal, and may perform the demodulation to determine the RTS or ACK / NACK sequence.

If the demodulated signal is ACK in step 804, the receiver transmits a beacon signal to the SPD in step 806.

If the demodulated signal is NACK in step 804, the PPD transmits a beacon signal in step 808.

The algorithm of the present invention is then terminated.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, in a wireless communication system based on wireless recognition, by combining a control channel sequence and a DQPSK modulation symbol, there is an advantage in that a receiver can receive a beacon signal directly and flexibly without demodulation.

1 is a view illustrating a structure of a request to send (RTS) and an acknowledgment / negative-acknowledgment period (ANP) slot according to the prior art;

2 is a view illustrating an operation of a beacon for protecting terminals of a licensed frequency band in a wireless communication system based on wireless recognition according to an embodiment of the present invention;

3 is a diagram illustrating an RTS and ANP slot structure according to an embodiment of the present invention;

4 is a beacon transmitter in a wireless communication system based on wireless recognition according to an embodiment of the present invention;

5 is a beacon receiver in a wireless communication system based on wireless recognition according to an embodiment of the present invention;

6 is a beacon receiver in a wireless communication system based on wireless recognition according to another embodiment of the present invention;

7 is a flowchart illustrating an operation of a beacon transmitter in a wireless communication system based on wireless recognition according to an embodiment of the present invention;

8 is a flowchart illustrating an operation of a beacon receiver in a wireless communication system based on wireless recognition according to an embodiment of the present invention;

9 is a communication procedure diagram between a primary protecting device (PPD) and a secondary protecting device (SPD).

Claims (27)

A beacon transmitter in a wireless communication system based on wireless recognition, A sequence generator which generates a control sequence having orthogonality in a binary domain and a quaternary domain; And a transmitter for transmitting the generated control sequence. The method of claim 1, And the control sequence is one of Request To Send (RTS) or ACKnowledgment (ACK) / Negative-ACKnowledgment (NACK). The method of claim 2, The RTS and the ACK / NACK is characterized in that the same symbol size is transmitted divided by the symbol time. The method of claim 2, The sequence for the RST and the NACK is (00, 11, 00, 11) and the modulation symbol is (-1-j, -1-j, 1 + j, 1 + j), and the sequence for the ACK is ( 11, 00, 11, 00) and the modulation symbol is (1 + j, -1-j, -1-j, 1 + j). The method of claim 2, The RST is transmitted to inform that there is data to be transmitted. The method of claim 1, The transmitting unit A serial-to-parallel converter for converting the generated control sequence from serial to parallel; A modulator for modulating the parallel control sequence into modulation symbols A diffusion unit to multiply and spread the modulation symbol and a spreading code; And a pillar shape unit configured to pulse-shape and output the spread modulation symbol. The method of claim 6, The modulation method is characterized in that for using differential quadrature phase shift keying (DPQPK). The method of claim 6, And a direct sequence spread spectrum (DSSS) as the spreading method. In a beacon receiver in a wireless communication system based on wireless recognition, A matching filter unit for detecting a signal, A despreader for despreading the detected signal and outputting the modulated symbol; Correlating the despread modulation symbol with a control sequence, And a determination unit to determine a corresponding control sequence from the correlation result value. The method of claim 9, The correlator A first correlator for performing correlation between the despread modulation symbol and an ACK sequence; And a second correlation unit for performing correlation between the despread modulation symbol and a NACK sequence. In a beacon receiver in a wireless communication system based on wireless recognition, A matching filter unit for detecting a signal, A despreader for despreading the detected signal and outputting the modulated symbol; A demodulator for demodulating the despread modulation symbol; And a comparing unit to determine a corresponding control sequence by comparing the demodulated output bits with a control sequence. The method of claim 9 or 11, And the control sequence is one of Request To Send (RTS) or ACKnowledgment (ACK) / Negative-ACKnowledgment (NACK). A beacon transmission method in a wireless communication system based on wireless recognition, Generating a control sequence having orthogonality in the binary domain and the quaternary domain; Transmitting the generated control sequence. The method of claim 13, The control sequence is characterized in that one of Request To Send (RTS) or ACK (ACKnowledgment) / NACK (Negative-ACKnowledgment). The method of claim 14, The RTS and the ACK / NACK is characterized in that the same symbol size is transmitted divided by the symbol time. The method of claim 14, The sequence for the RST and the NACK is (00, 11, 00, 11) and the modulation symbol is (-1-j, -1-j, 1 + j, 1 + j), and the sequence for the ACK is ( 11, 00, 11, 00) and the modulation symbol is (1 + j, -1-j, -1-j, 1 + j). The method of claim 14, The RST is transmitted to indicate that there is data to transmit. The method of claim 13, The process of transmitting the generated control sequence is Converting the generated control sequence from serial to parallel, Modulating the parallel control sequence with a modulation symbol; Multiplying and spreading the modulation symbol and a spreading code; And pulse shaping and outputting the spread modulation symbol. The method of claim 18, The modulation method is characterized by using differential quadrature phase shift keying (DPQPK). The method of claim 18, And using direct sequence spread spectrum (DSSS) as the diffusion method. A beacon receiving method in a wireless communication system based on wireless recognition, Detecting the signal, Despreading the detected signal and outputting the modulated symbol; Correlating the despread modulation symbol with a control sequence; Determining the control sequence from the correlation result value. The method of claim 21, The process is performed by correlating the despread modulation symbol with a control sequence. Performing a correlation between the despread modulation symbol and an ACK sequence; And performing correlation between the despread modulation symbol and a NACK sequence. A beacon receiving method in a wireless communication system based on wireless recognition, Detecting the signal, Despreading the detected signal and outputting the modulated symbol; Demodulating the despread modulation symbol; And comparing the demodulated output bit with a control sequence to determine a corresponding control sequence. The method of claim 21 or 23, The control sequence is characterized in that one of Request To Send (RTS) or ACK (ACKnowledgment) / NACK (Negative-ACKnowledgment). In the wireless communication system based on the radio beacon (beacon) transmission, A first beacon device that transmits a Request To Send (RTS) upon data transmission; And a second beacon device for transmitting an ACKnowledgment (ACK) or a negative-ACKnowledgment (NACK) after the RTS is transmitted. The method of claim 25, The second beacon device transmits a beacon signal when the ACK is received, and the first beacon device transmits a beacon signal when the NACK is transmitted. The method of claim 25, The RTS is transmitted to the second beacon device to indicate that there is data to transmit, and the ACK or the NACK is sent to the first beacon device to indicate whether data transmission is allowed.