KR20060014557A - Apparatus and method for transmitting/receiving of reference signal - Google Patents

Abstract

The present invention relates to a method for generating and transmitting a reference signal transmitted and received for communication between a subscriber station and a base station, comprising: grouping an arbitrary reference signal in which +1 and -1 are repeated according to a predetermined number of groups; Generating new reference signals by adding a first variable necessary for a group identification correlation operation to a +1 and -1 of each of the group signals, and multiplying a second variable for increasing a reference signal transmission power; And selecting and transmitting a reference signal differently for each base station among the newly generated reference signals.

Orthogonal Sequences, Preambles, Correlation Operations, Autocorrelation

Description

Reference signal transmission and reception apparatus and method {APPARATUS AND METHOD FOR TRANSMITTING / RECEIVING OF REFERENCE SIGNAL}             

1 schematically illustrates a frame structure used in a general TDD-OFDMA communication system.

2 is a diagram illustrating a sequence detection apparatus of a subscriber station according to an embodiment of the present invention.

3 is a flowchart illustrating a sequence detection process of a subscriber station according to an embodiment of the present invention.

4 is a diagram illustrating an internal structure of a transmitter of an OFDM communication system to which an embodiment of the present invention is applicable.

5 is a diagram illustrating an internal structure of a receiver of an OFDM communication system to which an embodiment of the present invention is applicable.

6 is a graph showing the simulation performance test results between the preamble proposed in the present invention and the existing preamble

The present invention relates to an apparatus and a method for transmitting and receiving a reference signal.

In general, orthogonal or quasi-orthogonal sequences are used for effective signal detection of a transmitting and receiving end in a communication system. That is, when the transmitting end selects an arbitrary orthogonal sequence among predefined sets of orthogonal sequences and maps the data to the receiving end, the receiving end correlates the received signal using a correlation function. In this way, the receiving end is correlated and finds that the signal indicating the maximum output power is the signal to be received. In other words, the orthogonal or quasi-orthogonal sequence is a reference signal for detecting a signal between a transmitter and a receiver.

A method of generating and detecting a signal using the orthogonal sequence is applied and operated in most communication systems. Hereinafter, for convenience of description, it will be described as an Institute of Electrical and Electronics Engineers (IEEE) 802.16d communication system of the communication system.

The IEEE 802.16d communication system uses a preamble sequence to acquire synchronization between a base station and a subscriber station. The preamble sequence is an example of a representative orthogonal sequence. Therefore, hereinafter, the description of the orthogonal sequence will be replaced with the description of the preamble sequence.

The IEEE 802.16d communication system employs an Orthogonal Frequency Division Multiple Access (OFDMA) scheme to support a broadband transmission network. In addition, the IEEE 802.16d communication system is a broadband wireless access communication system using a Time Division Duplexing (OFDDD) -OFDMA scheme (hereinafter, referred to as TDD-OFDMA). The broadband wireless access communication system is a system supporting a wireless communication service, and is composed of a base station and a subscriber station. The base station and the subscriber station support a wireless communication service using a transmission frame. Accordingly, the base station and the subscriber station must acquire mutual synchronization for transmission and reception of a transmission frame, and for the synchronization acquisition, the base station acquires a synchronization signal so that the subscriber station knows the start of a frame transmitted from the base station. Send it.

Then, the subscriber station receives the synchronization signal transmitted by the base station, checks the frame timing of the base station, and demodulates the received frame according to the checked frame timing. In addition, the synchronization signal generally uses a specific preamble sequence previously promised by the base station and the subscriber station.

Next, a frame structure used in a general TDD-OFDMA communication system will be described with reference to FIG. 1.

1 is a diagram schematically illustrating a frame structure used in a general TDD-OFDMA communication system.                         

Referring to FIG. 1, first, a frame used in the TDD-OFDMA is called a downlink (hereinafter referred to as DL) 149 section and an uplink (UL). The section 153 is divided by time. In the transition period from the DL 149 to the UL 153, a Transmission Transition Gap (TTG) 151 transitions back to the DL 149 from the UL 153 with a guard time. In the interval, a reception transition gap (RTG) 155 configures a guard time. Meanwhile, the TDD-OFDMA frame includes a vertical axis composed of a plurality of subchannels 147 and a horizontal axis composed of an OFDMA symbol 145.

Then, referring to the DL 149, the DL 149 is a preamble (111) for the synchronization acquisition in the K OFDMA symbols, the frame control in the K + 1 or K + 2 OFDMA symbols Broadcast data information to be commonly received by subscriber stations such as a header (FCH: frame control header, FCH) 113, DL_MAP 115, and UL_MAP 117 is located. In this case, the FCH 113 is composed of two sub-channels and delivers basic information on sub-channels, ranging and modulation methods. Downlink bursts (DownLink Burst, hereinafter referred to as 'DL burst') (121, 123, 125, 127, 129) are located from the K + 2 OFDMA symbol to the K + 8 OFDMA symbol except the UL_MAP. . Next, the UL [)] Referring to 153, the UL 153 is K + 9 preamble (131, 133, 135) are located at the OFDMA symbols, and, in K + 10 OFDMA symbols to K + 12 OFDMA symbols Each uplink burst (hereinafter, referred to as an 'UL burst') 137, 139, and 141 is located. In addition, the ranging subchannel 143 for ranging in the K + 9 to K + 12 OFDMA symbol is located.

Information regarding the location and allocation of the UL bursts 137, 139, and 141 and the DL bursts 121, 123, 125, 127, and 129 may be used to control an arbitrary cell through the DL_MAP 115 and the UL_MAP 117. The base station informs the subscriber stations belonging to the cell, and the subscriber stations are variably allocated a subchannel combining a frequency and a symbol every frame through the information to perform communication.

In this case, the subscriber station detects a specific signal pattern of the preamble located in the DL section 149 and the UL section 153 to recognize the start point of the frame. For example, in a multi cell environment, the preamble is defined in a unique form that is different for each cell. In addition, different preambles are designed to be orthogonal to each other or quasi orthogonal to each cell in order to maximize detection probability. In this way, the subscriber station located in an arbitrary cell sequentially correlates the preambles stored in advance with the preambles of the frame, and then determines the reference preamble signal having the largest correlation value as the correct preamble signal.

Meanwhile, as the number of reference preambles stored in advance by the subscriber station increases, the amount of correlation computation increases, and thus serves as a load of the subscriber station. In addition, the detection time for the subscriber station to determine the correct preamble becomes long. Therefore, the subscriber station fails to perform the purpose of using the preamble, that is, synchronization acquisition, base station discrimination, and channel estimation. In conclusion, there is a need for a method of reducing the preamble detection time for a case where the number of reference preambles is large.

Accordingly, it is an object of the present invention to provide a reference signal transmission apparatus and method for reducing the reference signal detection time and the amount of calculation calculation.

Another object of the present invention is to provide a reference signal receiving apparatus and method for reducing the reference signal detection time and the amount of detection calculation.

The first method of the present invention for achieving the above objects; A method for generating and transmitting a reference signal transmitted / received for communication between a subscriber station and a base station, the method comprising: grouping an arbitrary reference signal having +1 and -1 repeated corresponding to a predetermined number of groups; Generating new reference signals by adding a first variable necessary for a group identification correlation operation to each of +1 and -1, and multiplying a second variable for increasing a reference signal transmission power; And selecting and transmitting a reference signal differently for each base station among the reference signals.

A second method of the present invention for achieving the above objects; A method of determining a reference signal transmitted and received for communication between a subscriber station and a base station, wherein any reference signal with +1 and -1 repeated is grouped according to a predetermined number of groups, and + of each of the divided group signals The reference signal differently selected for each base station among the newly generated reference signals is multiplied by 1 and -1 by adding a first variable required for a group identification correlation operation and multiplying a second variable for increasing a reference signal transmission power. A process of receiving from a base station, identifying a group of the received reference signals, correlating a plurality of reference signals belonging to the identified group with the received reference signals, and having a maximum correlation value And finally determining the signal as the received reference signal.

A first apparatus of the present invention for achieving the above objects; An apparatus for transmitting a reference signal transmitted and received for communication between a subscriber station and a base station, wherein any reference signal with +1 and -1 repeated is grouped according to a predetermined number of groups, and each of the divided group signals + 1 and -1, add a first variable required for the group identification correlation operation, multiply a second variable to increase the reference signal transmission power to generate new reference signals, base stations of the newly generated reference signals It characterized in that it comprises a reference signal generator for selecting and transmitting a reference signal differently.

A second device of the present invention for achieving the above objects; An apparatus for determining a reference signal transmitted and received for communication between a subscriber station and a base station, wherein any reference signal in which +1 and -1 are repeated is grouped according to a predetermined number of groups, and + of each of the divided group signals is +. The reference signal differently selected for each base station among the newly generated reference signals is multiplied by 1 and -1 by adding a first variable required for a group identification correlation operation and multiplying a second variable for increasing a reference signal transmission power. Correlating a plurality of correlators received from a base station, a first extractor identifying the group of received reference signals, a plurality of reference signals belonging to the identified group, and a received reference signal, respectively, for maximum correlation And a second extractor which finally determines the reference signal having the value as the received reference signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted without departing from the scope of the present invention.

The present invention proposes a reference signal transmission / reception apparatus and method that can reduce the number of correlation operations when detecting a reference signal from N times to 2rootN times. A representative example of the reference signal is a preamble sequence, and the present invention will be described as an Institute of Electrical and Electronics Engineers (IEEE) 802.16d communication system among various communication systems using the preamble sequence.

Prior to the description of the present invention, the preamble is a signal that is pre-defined between the base station and the subscriber station to detect the starting point of the frame. For example, the IEEE 802.16d communication system has a multi-cell structure and uses different preambles for each of the plurality of cells. Accordingly, the subscriber station located in an arbitrary cell detects the preamble having the maximum peak by performing correlation and auto correlation between the reference preambles and the preamble of the received signal. The preamble is defined as a sequence of +1 and -1 in the frequency domain, and is orthogonal or quasi orthogonal between different preambles. In the IEEE 802.16d communication system, the following preambles exist. In the following preamble sequence, + means +1 and-means -1.

가 된다.If the preamble is referred to as Sequence 1 and expressed as a formula

Becomes

Another preamble includes the following preambles.

가 된다.When the preamble is called a sequence 2 and expressed as a formula

Becomes

는 모두 주파수 영역에서 정의된 수열이며, 기지국은 상기

또는

수열들을 역고속 푸리에 변환(IFFT: Inverse Fast Fourier Transform, 이하 'IFFT'라 칭하기로 한다)하여 가입자 단말기로 송신한다. 상기 IFFT 이후의 신호는 시간 영역의 신호로

로 나타낼 수 있다. 여기서,

은 n번째 시간 신호 샘플값이다. 따라서, 상기 가입자 단말기는 상기 수신한

를 고속 푸리에 변환(FFT: Fast Fourier Transform, 이하 'FFT'라 칭하기로 한다)하여 주파수 영역의 신호

로 변환한다. remind

Are all sequences defined in the frequency domain, and the base station

or

The sequences are transmitted to the subscriber station by performing an Inverse Fast Fourier Transform (IFFT). The signal after the IFFT is a signal in the time domain

It can be represented by. here,

Is the n th time signal sample value. Accordingly, the subscriber station receives the received

Signal in the frequency domain by fast Fourier transform (FFT).

Convert to

은 다른 값 r[n]으로 왜곡되며, r[n]은 FFT에 의해 R[k]로 변환된다. 상기 R[k]는 수신된 시간 영역의 신호를 FFT를 통해 변환된 주파수 영역의 신호이다. 상기 가입자 단말기는 상기 R[k]와 기준 프리앰블

와 상관 연산 수행 후 가장 큰 상관값

을 갖도록 하는

를 선택한다. 여기서, 상기 상관 연산에 사용되는 상관 함수는 하기 수학식 1과 같이 정의된다. Generally, the transmission signal in the time domain in the presence of distortion such as noise in the transmission channel

Is distorted to another value r [n], and r [n] is converted to R [k] by the FFT. The R [k] is a signal in the frequency domain obtained by converting the received time domain signal through the FFT. The subscriber station includes the R [k] and a reference preamble.

Correlation value after performing the

To have

Select. Here, the correlation function used for the correlation operation is defined as in Equation 1 below.

As described above, when the preamble is detected by the general method, as the number of reference preambles increases, the amount of correlation calculation and the preamble detection time increase in proportion to the number of reference preambles.

Therefore, in the present invention, the orthogonality of the orthogonal sequence is partially impaired, so that the amount of correlation computation is reduced to reduce the time required for preamble detection.

An arbitrary vector signal set S is defined as in Equation 2 below.

는 크로너커 델타 함수(kronecker delta function)이다. 상기 크로너커 델타 함수는 i=k 인 경우에 대해서만

가 된다.In Equation 2, N = nm, and n and m are positive integers. In addition, M> 0,

Is the kronecker delta function. The Kroner delta function is only for the case where i = k

Becomes

First, assuming that the defined S a m divided into groups S _1, S _2, ...., respectively, S _m, and can be represented as shown in equation (3).

이 상기 S내의 모든

와도 직교한다고 가정한다. 즉,

,

와 같이 가정할 수 있다.Where orthogonal to each other

All within this S

Assume that is also orthogonal with. In other words,

,

We can assume

를 더하고,

를 곱해 새로운 집합 T_k를 만든다. 여기서, 상기 각 벡터들에 더해지는

는 가입자 단말기가 그룹 식별, 즉, 각 그룹별 상관 연산을 수행하기 위한 파라미터이다. 또한,

을 곱하는 이유는 신호를 일정수의 그룹 신호를 분할하기 이전과 동일하게 전력비를 맞춰주기 위함이다. 다시 말하자면, 상기 수학식 2에 나타낸 신호 S를 전송하는데에 '1'이라는 전력이 소요된다면, 상기 수학식 3에 나타낸 각각의 신호들을 전송하는데에는 '1'보다 작은 전력이 소요될 수 밖에 없다. 그러나, 상기 각각의 신호들(S₁,S₂,....,S_m)들이 기준 신호들임을 감안하면, 높은 전력으로 송신되는 것이 바람직하기 때문에

을 곱해 전력 증대(power boosting)를 하는 것이다. 한편, 상기 T_k를 하기 수학식 4와 같이 나타낼 수 있다. In each vector of S _k according to the above assumption

Add,

Multiply by to make a new set T _k . Here, added to each of the vectors

Is a parameter for the subscriber station to perform group identification, that is, correlation operation for each group. Also,

The reason for multiplying is to adjust the power ratio in the same way as before dividing a signal of a predetermined number of group signals. In other words, if a power of '1' is required to transmit the signal S shown in Equation 2, a power smaller than '1' is inevitably required to transmit each signal shown in Equation 3. However, considering that the respective signals S ₁ , S ₂ ,..., S _m are reference signals, it is preferable to transmit at high power.

Multiply by to get power boosting. Meanwhile, T _k may be represented as in Equation 4 below.

에 속한 임의의 벡터가 된다.According to Equation 4, the transmission signal sequence is

Is any vector belonging to.

라고 가정한다. 상기 가입자 단말기는 먼저 상관 함수

가 최대값이 되는

를 검출한다. 상기 송신 신호 수열 가정에 따른 상기 상관 함수를 하기 수학식 5와 같이 나타낼 수 있다.Next, the preamble detection algorithm performed by the subscriber station will be described. Transmit signal sequence

Assume that The subscriber station first performs a correlation function

Is the maximum value

Detect. The correlation function according to the transmission signal sequence assumption may be expressed by Equation 5 below.

일 때, 상기

가 최대값을 가진다. 이것은

을 의미한다. 다음으로,

를 최대화하는

를 선택한다. 여기서,

가 되므로,

일 때

가 최대값을 가 진다. 따라서, 상기 가입자 단말기는 최종 결정된 수신 신호를

로 결정한다. 상기 가입자 단말기가

을 결정하는데 걸리는 상관 연산 횟수는 m이고,

중에서 하나를 고르는데 걸리는 상관 연산 횟수는 n이므로, 총 상관 횟수는 n+m<nm=N이 되므로, N이 큰 경우 상관 연산 횟수를, 대략

으로 크게 줄일 수 있다.In Equation 5,

When

Has the maximum value. this is

Means. to the next,

To maximize

Select. here,

Becomes,

when

Has a maximum value. Accordingly, the subscriber station receives the final determined received signal.

Decide on The subscriber station

The number of correlation operations it takes to determine is m,

Since the number of correlation operations it takes to select one out of n is n, the total number of correlations is n + m <nm = N, so if N is large,

Can be greatly reduced.

Next, a sequence detection apparatus of a subscriber station according to an embodiment of the present invention will be described with reference to FIG. 2.

2 is a diagram illustrating a sequence detection apparatus of a subscriber station according to an embodiment of the present invention.

(201)를 상관기들(202, 204, 206)로 입력하여 상관 연산을 수행한다. 여기서, 최초 상관 연산으로 결정되는 것은 상기 수학식 3에 나타낸 바와 같은 최대 상관값을 가지는 그룹 결정이다. 즉, 도 2에 도시된 바와 같이, 상기 상관기들(202, 204, 206)은 상기 수신 수열

(201)와, 그룹핑된 수열 집합

와 상관 연산한 상관 연산값을 제1추출기(208)로 출력한다. 상기 제1추출기(208)는 상기 입력한 상관값들 중 가장 큰 상관값을 가지는 그룹

을 선택한다. 상기 제1추출기(208)는 상기 선택된 그룹

의 그룹 인덱스인 l을 다중화기(multiplexor)(212)로 출력한다.Referring to FIG. 2, first, the subscriber station receives the received sequence.

Input 201 to the correlators 202, 204, 206 to perform a correlation operation. Here, what is determined by the initial correlation operation is a group decision having the maximum correlation value as shown in Equation (3) above. That is, as shown in Figure 2, the correlators 202, 204, 206 are the receiving sequence

201 and grouped sequence sets

The correlation calculation value correlated with and is output to the first extractor 208. The first extractor 208 is a group having the largest correlation value among the input correlation values.

Select. The first extractor 208 is the selected group

The group index of L is output to the multiplexer 212.

의 각 벡터에

를 더하고,

를 곱해 새롭게 생성한 집합군(210)

중 상기 인덱스값 l에 해당하는 집합

을 선택하고 상관기들(214, 216, 218)로 출력한다. 상기 각각의 상관기들(214, 216, 218)은 상기 수신 수열

과, 상기

의

들과 각각 상관 연산 수행한 후, 상관 연산값들을 제2추출기(220)로 출력한다. 상기 제2추출기(220)는 상기 상관 연산한 값들을 입력하여 가장 큰 상관값을 가지는 인덱스(즉, 1~n 값 중 하나)를 선택하여 출력한다.On the other hand, the multiplexer 212 is the grouped sequence set as shown in equation (4)

On each vector of

Add,

Multiplying the newly created set group (210)

Set corresponding to the index value l among

Is selected and output to the correlators 214, 216, 218. Each of the correlators 214, 216, 218 is the received sequence.

And above

of

After performing the correlation operation with each other, the correlation calculation values are output to the second extractor 220. The second extractor 220 inputs the correlation values and selects and outputs an index (ie, one of 1 to n values) having the largest correlation value.

Next, the sequence detection process of the subscriber station according to the embodiment of the present invention will be described with reference to FIG. 3.

3 is a flowchart illustrating a sequence detection process of a subscriber station according to an embodiment of the present invention.

을 수신하고 304단계로 진행한다. 상기 304단계에서 상기 가입자 단말기는 상기

과, 그룹핑된 수열 집합

와 상관 연산을 수행하여 가장 큰 상관값을 가지는 그룹

을 선택하고 306단계로 진행한다. 상기 306단계에서 상기 가입자 단말기는 상기 선택된 그룹 인덱스에 상응한 새로운 수열 집합

을 선택하고 308단계로 진행한다. 상기 308단계에서 상기 가입자 단말기는

가 최대값을 가지는 k를 선택하고 310단계로 진행한다. 상기 310단계에서 상기 가입자 단말기는 최종 수신 신호를

로 결정한다. Referring to FIG. 3, in step 302, the subscriber station receives a signal sequence transmitted from a base station.

Received and proceeds to step 304. In step 304 the subscriber station is

And grouped sequence sets

The group with the highest correlation by performing the correlation operation with

Select and proceed to step 306. In step 306, the subscriber station sets a new sequence set corresponding to the selected group index.

Select and proceed to step 308. In step 308, the subscriber station

Selects k having the maximum value and proceeds to step 310. In step 310, the subscriber station transmits a final received signal.

Decide on

Next, an internal structure of a transmitter of an OFDM communication system to which an embodiment of the present invention is applicable will be described with reference to FIG. 4.

4 is a diagram illustrating an internal structure of a transmitter of an OFDM communication system to which an embodiment of the present invention is applicable.

4, the transmitter includes a modulator 401, a preamble generator 403, a modulator 405, a selector 407, and a serial to parallel converter 409. ), IFFT unit 411, parallel to serial converter 413, guard interval inserter 415, and digital to analog converter ( 417 and a radio frequency (RF) processor 419.

First, when data to be transmitted, that is, information data bits, is generated, the information data bits are input to the modulator 401. The modulator 401 modulates the input information data bits in a predetermined modulation scheme to generate a modulation symbol and outputs the modulated symbols to the selector 407. Here, the modulation scheme may be a quadrature phase shift keying (QPSK) scheme or a quadrature amplitude modulation (16QAM) scheme.

In addition, the preamble generator 403 to which the present invention is applied generates a preamble that is a quasi-orthogonal sequence that artificially degrades orthogonality, and outputs the preamble to the modulator 405. More specifically, the preamble generator 403 divides an arbitrary signal set into a predetermined number of groups, adds beta_k to each of the grouped signals, and multiplies 1 / root2 to generate new signals. The modulator 405 inputs a signal output from the preamble generator 403, modulates the signal in a preset modulation scheme, generates a modulated symbol, and outputs the modulated symbol to the selector 407. Here, a binary phase shift keying (BPSK) scheme may be used as the modulation scheme.

The selector 407 controls to output the signal output from the modulator 401 to the serial / parallel converter 409 when the transmitter is in a data symbol transmission interval in which a current data symbol should be transmitted. In the pilot symbol transmission period in which the transmitter should transmit the current pilot symbol, the transmitter outputs the signal output from the modulator 405 to the serial / parallel converter 409. The serial / parallel converter 409 inputs the serial modulation symbols output from the selector 407, converts them in parallel, and then outputs them to the IFFT unit 411. The IFFT unit 411 inputs a signal output from the serial / parallel converter 409 to perform an N-point IFFT and then outputs the signal to the parallel / serial converter 413.

The parallel / serial converter 413 inputs the signal output from the IFFT device 411 to serially convert the signal and outputs the serial signal to the guard interval inserter 415. The guard interval inserter 415 inputs the signal output from the parallel / serial converter 413 to insert the guard interval signal and outputs the guard interval signal to the digital / analog converter 417. Here, the guard interval is inserted to remove interference between the OFDM symbol transmitted at the previous OFDM symbol time and the current OFDM symbol transmitted at the current OFDM symbol time when the OFDM symbol is transmitted in the OFDM communication system. . In addition, the guard interval is a 'Cyclic Prefix' method of copying the last predetermined samples of the OFDM symbols in the time domain and inserting them into the valid OFDM symbols, or by copying the first predetermined samples of the OFDM symbols in the time domain. Inserted using any one of the 'Cyclic Postfix' method to insert into the symbol.

The digital-to-analog converter 417 inputs the signal output from the guard interval inserter 415, converts the analog signal, and outputs the analog signal to the RF processor 419. Here, the RF processor 419 includes components such as a filter and a front end unit, and transmits the signal output from the digital-to-analog converter 417 on actual air. After RF processing, the antenna transmits the air through an antenna.

In FIG. 4, an internal structure of a transmitter of an OFDM communication system to which an embodiment of the present invention is applicable has been described. Next, an internal structure of a receiver of an OFDM communication system to which an embodiment of the present invention is applicable will be described with reference to FIG. 5. .

5 is a diagram illustrating an internal structure of a receiver of an OFDM communication system to which an embodiment of the present invention is applicable.

Referring to FIG. 5, the receiver includes an RF processor 501, an analog / digital converter 503, a guard interval remover 505, and a serial / parallel converter. 507, FFT 509, parallel / serial converter 511, selector 513, demodulators 515, 517, and preamble detector 519.

First, a signal transmitted from a transmitter of the OFDM communication system is received through an antenna of the receiver in the form of a multipath channel and a noise component added thereto. The signal received through the antenna is input to the RF processor 501, and the RF processor 501 down converts the signal received through the antenna to an intermediate frequency (IF) band. After the output to the analog-to-digital converter 503. The analog-to-digital converter 503 digitally converts the analog signal output from the RF processor 501 and outputs the digital signal to the guard interval remover 505.

The guard interval remover 505 removes the guard interval signal by inputting the signal output from the analog / digital converter 503 and outputs the signal to the serial / parallel converter 507. The serial / parallel converter 507 inputs the serial signal output from the guard interval eliminator 505 to perform parallel conversion and outputs the serial signal to the FFT unit 509. The FFT unit 509 performs an N-point FFT on the signal output from the serial / parallel converter 507 and then outputs the signal to the parallel / serial converter 511.

The parallel / serial converter 511 inputs a parallel signal output from the FFT unit 509 to perform serial conversion and outputs the serial signal to the selector 513. The selector 513 controls to output the signal output from the FFT 509 to the demodulator 515 when the receiver is in a data symbol reception interval in which the receiver should receive the current data symbol, and the receiver controls the current preamble. In the case of the section to be received, the signal output from the FFT unit 509 is controlled to be output to the demodulator 517. The demodulator 515 demodulates the signal output from the FFT 509 in accordance with the modulation scheme applied by the transmitter and restores the data, that is, the information data bits.

Meanwhile, the demodulator 517 demodulates the signal output from the FFT 509 according to the modulation scheme applied by the transmitter, restores the signal to the preamble, and outputs the signal to the preamble detector 519. The preamble detector 519 inputs a signal output from the demodulator 517 to determine a preamble having a maximum correlation value.

6 is a graph illustrating a simulation performance test result between the preamble proposed in the present invention and the existing preamble.

The orthogonal preamble used for the simulation performance experiment of FIG. 6 is made of a Hadamard matrix. We experimented with selecting 100 orthogonal vectors from the row vectors of the 1024x1024 Hadamard determinant and 100 orthogonal vectors from the row vectors of the 512x512 Hadamard determinant. The channel model is a mobile vehicle based on ITU-R (International Telecommunication Union-Radiocommunication Sector), and the moving speed of the subscriber station is 60 km / h. The maximum Doppler spread is about 130 Hz and the channel bandwidth is 10 MHz. Adjacent cell interference resulting from a multi-cell environment can be approximated with additive white Gaussian noise (AWGN). In this experiment, the probability of correct estimation of the preamble was derived for the case where the carrier to interference ratio is -20, -15, -10, -5, and 0 dB.                     

It can be seen that the proposed sequence of the present invention has the same performance as that of the conventional method in the case where the autocorrelation value is 512 or more and the signal-to-interference ratio is less than -10 dB, although the number of correlations required for determining the received signal is smaller than that of the conventional method. . That is, the sequence detection according to the proposed scheme approaches the same performance as the conventional scheme in the wider signal-to-noise ratio region as the autocorrelation value of the sequence vector increases. More specifically, when the autocorrelation value is 512, 90% or more detection performance is shown at -10dB or more, whereas the autocorrelation value 1024 shows 90% detection performance at -15dB.

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 defined not only by the scope of the following claims, but also by the equivalents of the claims.

으로 크게 줄일 수 있으면서도 성능면에서도 우수하다는 이점이 있다.As described above, when the reference signal proposed in the present invention is generated and transmitted to the subscriber station, the subscriber station transmits the number of correlation operations from the existing N.

It can be greatly reduced, but also has an advantage in terms of performance.

Claims (16)

A method for generating and transmitting a reference signal transmitted and received for communication between a subscriber station and a base station, Grouping any reference signal in which +1 and -1 are repeated according to a predetermined number of groups; Generating new reference signals by adding a first variable required for a group identification correlation operation to a +1 and -1 of each of the divided group signals, and multiplying a second variable for increasing a reference signal transmission power; , And selecting and transmitting a reference signal differently for each of the base stations from among the newly generated reference signals. The method of claim 1, The second variable value is

The method characterized in that. The method of claim 1, Wherein the first variable value adds a different value for each of the divided groups. A method for determining a reference signal transmitted and received for communication between a subscriber station and a base station, Any reference signals, in which +1 and -1 are repeated, are grouped in correspondence with a predetermined number of groups, and to the +1 and -1 of each of the divided group signals, a first variable necessary for a correlation for group identification is added. Receiving a reference signal differently selected for each base station from among the newly generated reference signals by multiplying a second variable for increasing a reference signal transmission power, Identifying the group of received reference signals; And correlating a plurality of reference signals belonging to the identified group with a received reference signal, and finally determining a reference signal having a maximum correlation value as a received reference signal. The method of claim 4, wherein Wherein the first variable value adds a different value for each of the divided groups. The method according to claim 4 and 5, The group identification of the reference signal correlates the received reference signal with first variable values having different values for each divided group to determine a first variable value having a maximum correlation value, thereby determining the determined first variable. And determining a group corresponding to the value as a group to which the reference signal belongs. The method of claim 4, wherein The second variable value is

The method characterized in that. The method of claim 4, wherein The correlation operation is performed using Equation 6 below.

In Equation 6,

Denotes a kronecker delta function, and C denotes a correlation function. An apparatus for transmitting a reference signal transmitted and received for communication between a subscriber station and a base station, Group any reference signal in which +1 and -1 are repeated in correspondence with a predetermined number of groups, and add +1 and -1 to each of the divided group signals, and add a first variable necessary for a correlation operation for group identification. And a reference signal generator for generating new reference signals by multiplying a second variable for increasing a reference signal transmission power, and selecting and transmitting a reference signal differently for each base station among the newly generated reference signals. Said device. The method of claim 9, The second variable value is

The device, characterized in that. The method of claim 9, And the first variable value adds a different value for each of the divided groups. An apparatus for determining a reference signal transmitted and received for communication between a subscriber station and a base station, Any reference signals, in which +1 and -1 are repeated, are grouped in correspondence with a predetermined number of groups, and to the +1 and -1 of each of the divided group signals, a first variable necessary for a correlation for group identification is added. A plurality of correlators for receiving from the base station a reference signal differently selected for each of the newly generated reference signals by multiplying a second variable for increasing a reference signal transmission power; A first extractor for identifying a group of the received reference signals; And a second extractor configured to correlate a plurality of reference signals belonging to the identified group with a received reference signal to finally determine a reference signal having a maximum correlation value as a received reference signal. Device. The method of claim 12, And the first variable value adds a different value for each of the divided groups. The method according to claim 12 and 13, The first extractor correlates the received reference signal with first variable values having different values for each divided group to determine a first variable value having a maximum correlation value. And determining a group corresponding to the determined first variable value as a group to which the reference signal belongs. The method of claim 12, The second variable value is

The device, characterized in that. The method of claim 12, The correlation operation is performed by using Equation 7 below.

In Equation 6,

Denotes a kronecker delta function, and C denotes a correlation function.

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