KR20120133336A - Apparatus and method for receiving signal of acquiring antenna diversity in a ofdm system - Google Patents

Abstract

PURPOSE: An antenna diversity obtaining apparatus and a method thereof for OFDM(Orthogonal Frequency Division Multiplexing) system are provided to obtain an antenna diversity in consideration of frequency selection fading with an SNR(Signal to Noise Ratio). CONSTITUTION: A plurality of receiving processing units(110A,110B) performs channel equalization of signals received through two or more antennas. A plurality of adaptive weight calculating units(210A,210B) calculates a channel power with an SNR. A plurality of adaptive weight calculating units calculates weight value of each receiving processing unit. A combining unit(131) combines each weight values calculated from the adaptive weight calculating units. [Reference numerals] (110A) First receiving processing unit; (110B) Second receiving processing unit; (111a) First RF unit; (111b) Second RF unit; (112a) First synchronizing unit; (112b) Second synchronizing unit; (113a) First FFT unit; (113b) Second FFT unit; (114a) First channel synchronizing unit; (114b) Second channel synchronizing unit; (131) Combining unit; (210A) First adaptive weight calculating unit; (210B) Second adaptive weight calculating unit; (211a) First channel power calculating unit; (211b) Second channel power calculating unit; (212a) First SNR presuming unit; (212b) Second SNR presuming unit; (213a) First weighted value calculating unit; (213b) Second weighted value calculating unit

Description

Apparatus and method for acquiring antenna diversity for orthogonal frequency division multiple access system {APPARATUS AND METHOD FOR RECEIVING SIGNAL OF ACQUIRING ANTENNA DIVERSITY IN A OFDM SYSTEM}

The present invention relates to an apparatus and method for obtaining antenna diversity in an orthogonal frequency division multiplexing (OFDM) system. In particular, the present invention can simplify antenna structure and improve antenna diversity gain. It is about technology.

Recently, an OFDM system is a communication method that has been in the spotlight in a wireless communication system, and has a merit of transmitting a large amount of data at a high speed, compared to a code division multiplexing (CDM) method, which is mainly used. The OFDM scheme is widely used in portable wireless communication systems capable of communicating with a large number of terminals, and also in DMA and DAB systems, which are one of local area network (LAN) and broadcast communication.

In such an OFDM system, a diversity scheme using multiple antennas may be used to receive wireless data more effectively. This diversity method is a technique for receiving a signal through each of two or more antennas, and by reconstructing the signal by reflecting the characteristics of the signal received at each of these antennas to obtain a more improved signal.

Therefore, in the present invention, in calculating the weight applied to the MRC scheme in an OFDM system that obtains antenna diversity using the Maximum Ratio Combining (MRC) scheme, the frequency selective fading along with the SNR of the received signal is used. An apparatus and method for acquiring antenna diversity in consideration of all characteristics are provided.

The present invention provides an apparatus and method for reducing the volume of hardware by applying weights according to modulation schemes in an OFDM system that obtains antenna diversity using the MRC technique.

The present invention provides an apparatus and method for providing an optimal weight in an environment with low reception sensitivity in consideration of the power of a received signal and the overall characteristics of an OFDM symbol in an OFDM system that acquires antenna diversity using the MRC technique. .

The present invention provides an apparatus and method capable of providing optimal MRC performance in an OFDM system that obtains antenna diversity using the MRC technique.

An apparatus according to an embodiment of the present invention is an apparatus for acquiring antenna diversity using a maximum-non-combination (MRC) technique in an OFDM system, and a signal for channel equalizing and outputting a signal received through each antenna Reception processing units provided with numbers corresponding to the respective antennas; An adaptive weight calculator which calculates a symbol-to-noise ratio (SNR) and channel power in each channel equalized signal output from the receivers and calculates weights of the receivers through a product thereof; And a combining unit which combines the equalized signals output from the respective reception processors by using the weights of the respective reception processors calculated by the adaptive weight calculator.

In addition, the adaptive weight calculation unit,

A channel power calculator configured to calculate the channel power from the channel equalized signal; An SNR estimator for calculating the SNR from the channel equalized signal; And a weight calculator configured to calculate an adaptive weight by multiplying the channel power calculated by the channel power calculator and the estimated SNR.

It may be configured with a number corresponding to each of the receiving processing units.

In addition, the weight calculation unit,

The SNR reference value according to the modulation scheme is determined in advance, and when the estimated SNR value is larger than the predetermined SNR compared with the SNR received from the SNR estimation, the corrected SNR is set as the reference SNR. After setting the corrected SNR, the channel power received from the channel power calculator can be multiplied with the set SNR to calculate a weight.

The calculated weight may be cut from the least significant bit of the weight multiplied by the predetermined number of SNR bits by a modulation scheme so that the weight becomes a constant bit.

In addition, each of the receiving processing unit,

An RF unit converting a radio signal received from the antenna into a baseband signal; A synchronizer configured to output time and frequency synchronization of the baseband signal; An FFT unit for fast Fourier transforming the output of the synchronization unit; And a channel equalizer for channel equalizing the output of the FFT unit using a known signal.

A method according to an embodiment of the present invention is a method for obtaining antenna diversity using a maximum-non-combination (MRC) technique in an OFDM system, by channel equalizing a signal received through each antenna for each antenna A first process of outputting; A second step of calculating a symbol-to-noise ratio (SNR) and a channel power in each of the channel equalized signals and calculating weights of the received signal for each antenna through a multiplication thereof; And a third process of combining the channel equalized signals for each antenna by using the weights calculated for each antenna.

In addition, the second process,

Calculating the channel power from the channel equalized signal; Calculating the SNR from the channel equalized signal; And calculating the adaptive weight by multiplying the calculated channel power by the estimated SNR.

The third step,

A step 3-1 of determining an SNR reference value according to a modulation scheme in advance; A third step of setting the corrected SNR as the reference SNR when the estimated SNR value is larger than the predetermined SNR compared with the SNR received from the SNR estimation, and setting the estimated SNR as the corrected SNR when it is not large. ; Step 3-3 to calculate the weight by multiplying the channel power received from the channel power calculation unit with the set SNR;

The method may further include a step 3-4 of cutting the least significant bit of the weight multiplied by the predetermined number of SNR bits with respect to the calculated weight so that the weight becomes a constant bit.

In the present invention, the weight is calculated using the symbol-to-noise ratio (SNR) and the channel power according to the frequency selective fading characteristic of the OFDM symbol output from the fast Fourier transform (FFT) unit. . Through this, the present invention may consider not only components of reception sensitivity and signal reception power but also frequency selective fading characteristics. Therefore, the present invention can obtain the performance of the optimum maximum-non-coupling (MRC) scheme in the mobile environment.

In addition, in the present invention, the estimated SNR is determined to be a meaningful value only within a predetermined range by using only the SNR range for performance required according to the modulation scheme. Through this, in the present invention, since the weight of the MRC can be obtained, not only the number of bits for transmitting the weight can be reduced, but also the hardware structure of the combining unit can be simplified.

1 is a block diagram of an apparatus for acquiring reception diversity using multiple antennas in a general OFDM system.
2 is a block diagram of an apparatus for obtaining antenna diversity using an MRC scheme in an OFDM system according to the present invention;
3 is a control flowchart for calculating and weighting an SNR estimated according to a modulation scheme in a weight calculator according to the present invention;
4 is a control flow diagram for acquiring antenna diversity using the MRC scheme in accordance with the present invention in an OFDM system.

Hereinafter, the technical spirit of the present invention will be described in detail with reference to the accompanying drawings. On the other hand, it should be noted that the same reference numerals in the accompanying drawings used the same reference numerals.

The present invention described below will describe a receive antenna diversity structure in which a maximum ratio non-combining (MRC) technique is applied to an OFDM system. In this case, the combining weight is calculated using the symbol-to-noise ratio (SNR), which is the overall performance of the received signal, and the characteristics represented by the frequency selective fading by the multipath. In addition, the present invention will be described an apparatus and a control method that can obtain an improved gain with a simplified diversity structure by correcting the weight in consideration of the modulation scheme.

First, a configuration and an operation of an apparatus for acquiring reception diversity using multiple antennas in an OFDM system will be described first with reference to FIG. 1.

FIG. 1 is a block diagram of an apparatus for acquiring reception diversity using multiple antennas in a general OFDM system. 1 illustrates a case where only two antennas are used for convenience of description.

The first antenna ATN1 and the second antenna ANT2 respectively receive signals transmitted through different reception paths. The signal received through the first antenna ANT1 is processed by the first receiving processor 110A, and the signal received through the second antenna ANT2 is processed by the second receiving processor 110B. Here, the first receiving processor 110A and the second receiving processor 110B have a difference in processing signals received from different antennas ANT1 and ANT2, respectively, and generally go through the same process.

Hereinafter, the configuration and operation of the first reception processing unit 110A will be described, and the configuration and operation of the second reception processing unit 110B are the same as the configuration and operation of the first reception processing unit 110A. .

The first RF unit 111a converts the radio signal received from the first antenna ANT1 into a baseband signal and provides it to the first synchronizer 112a. The first synchronizer 112a then provides the baseband signal to the first Fast Fourier Transform (FFT) unit 113a in synchronization with time and frequency. The first FFT unit 113a converts the synchronized time domain signal into a frequency domain signal. In this way, the symbol converted into the frequency domain signal by the first FFT unit 113a is input to the first channel equalizer 114a. Accordingly, the first channel equalizer 114a performs an equalization process of the received symbol. Thereafter, the first channel equalizer 114a provides a signal obtained by equalizing the channel to the first weight calculator 121a and simultaneously provides the signal to the combiner 131. The above operation is that of the first receiving processing unit 110A.

As described above, the operation of the second receiving processor 110B is generally substantially the same as the operation of the first receiving processor 110A. Accordingly, the signal output from the second receiving processor 110B becomes a channel equalized signal from the second channel equalizer 114b as the signal received from the second antenna ANT2 is the same as that of the first receiving processor 110A. The second weight calculator 121b and the combiner 131 are provided.

Then, each weight calculator 121a, 121b calculates the weight of each subcarrier for MRC and provides them to the combining unit 131, respectively. Accordingly, the combining unit 131 obtains the antenna diversity gain by performing combining using the received signal received from each antenna ANT1 and ANT2 using channel equalized signals and calculated weight information, respectively.

Let's look again at the MRC method described above through the equations.

Output signals from the FFT units 113a and 113b received by the respective antennas ANT1 and ANT2 and included in the reception processing units 110A and 110B may be modeled as in Equation 1 below.

는 각각 k번째 부 반송파의 채널 특성, 전송 데이터, 잡음을 나타낸다. 또한 MRC를 위한 위한 각 안테나의 이론적인 가중치 (

)는 하기의 <수학식 2>와 같다.In Equation 1, 1 and 2 each represent a receiving antenna index, and P is a reception power of each antenna,

Denotes the channel characteristics, transmission data, and noise of the k-th subcarrier, respectively. Also the theoretical weight of each antenna for MRC (

) Is as shown in Equation 2 below.

과

는 각 안테나의 수신 SNR로 하기 <수학식 3>과 같이 표현할 수 있다.In Equation (2)

and

May be expressed as Equation 3 below by using the received SNR of each antenna.

In addition, the combining unit 131 using the MRC technique synthesizes a received signal as shown in Equation 4 below.

In the general OFDM system of FIG. 1 described above, the apparatus for acquiring antenna diversity calculates weights using SNRs, which are overall performances of OFDM signals, in the weight calculators 121a and 121b. Another method is to calculate weights using only frequency selective fading characteristics. In addition, in the salping method, a weighting method is used regardless of a modulation method of a transmitted signal. Therefore, the weights are calculated in the same way for all signals transmitted in different modulation schemes, so that a large number of bits of data for transmitting weights for combining must be allocated.

Meanwhile, in the OFDM system, not only the power of the received signal is changed by the wireless channel, but also the characteristics of each subcarrier are changed by frequency selective fading generated by the multipath. Therefore, in calculating the weight applied to the MRC scheme, both the SNR of the received signal and the characteristics of frequency selective fading must be considered.

In the above-described general OFDM system, a method of obtaining diversity is a case where a weight is configured using only the SNR of the received signal. In this case, since the frequency selective fading characteristic is not taken into account, the gain of the MRC is reduced in a multipath environment. On the other hand, if the weight is configured by considering only the channel characteristics of each subcarrier due to frequency selective fading, it is impossible to consider the power of the received signal and the characteristics of the entire OFDM symbol. none.

In addition, although the SNR operated according to the data modulation method is different, the above-described general technique of FIG. 1 does not consider this when calculating the weight applied to the MRC scheme. As a result, in an OFDM system using various modulation schemes, the estimated weight is expressed, and the number of bits for transmitting the same increases, thereby increasing the hardware structure for combining.

Then, in the reception diversity structure using the MRC scheme in the OFDM system according to the present invention, using the SNR of the received signal and the frequency selective fading characteristic by the multipath to improve the reception performance of the weight estimation and diversity of the MRC scheme An apparatus and a method for the same will be described. In addition, the present invention will also be described with an apparatus and a control method for simplifying the size of the system by reducing the data assigned to the weight by correcting the weight according to the modulation scheme of the received signal according to the various modulation schemes in the OFDM system will be.

2 is a block diagram of an apparatus for acquiring antenna diversity using an MRC scheme in an OFDM system. In the block structure of FIG. 2, the same parts as those of FIG. 1 use the same reference numerals. In addition, the present invention may be configured using a plurality of antennas, but for the convenience of description, only two antennas will be described.

Let us briefly look at the same configuration as in Figure 1 of the configuration of FIG.

The first RF unit 111a converts the radio signal received from the first antenna ANT1 into a baseband signal and provides it to the first synchronizer 112a. The first synchronizer 112a then provides the baseband signal to the first Fast Fourier Transform (FFT) unit 113a in synchronization with time and frequency. The first FFT unit 113a converts the synchronized time domain signal into a frequency domain signal. In this way, the symbol converted into the frequency domain signal by the first FFT unit 113a is input to the first channel equalizer 114a. Accordingly, the first channel equalizer 114a performs an equalization process of the received symbol.

Thereafter, the first channel equalizer 114a provides a signal in which the channel is equalized according to the present invention to the first channel power calculator 211a and the first SNR estimator 212a, and at the same time the combining unit 131. To provide. That is, it is provided to the first adaptive weight calculator 210A according to the present invention.

The same applies to the case of the second receiving processor 110B. That is, the operation until the second channel equalizer 114b is the same, except that the output of the second channel equalizer 114b is provided to the second channel power calculator 211b and the second SNR estimator 212b. At the same time, it is provided to the combining unit 131. Here too, the output of the second channel equalizer 114b is provided to the second adaptive weight calculator 210B according to the present invention.

In this case, the channel equalizers 114a and 114b may estimate the channel and perform channel compensation using a pilot signal known between the transmitter and the receiver in advance. Next, a process in which the signal output from the first reception processor 110A is processed by the first adaptive weight calculator 210A will be described. Here, the configuration and operation of the first adaptive weight calculator 210A and the second adaptive weight calculator 210B are the same.

The first channel power calculator 211a of the first adaptive weight calculator 210A calculates the channel power using the estimated channel for each subcarrier from the equalized signal received through the first antenna ANT1. . In addition, the second channel power calculator 211b of the second adaptive weight calculator 210B calculates the channel power by using the estimated channel for each carrier from the equalized signal received through the second antenna ANT2. do.

를 계산한다. 여기서

이며, N은 FFT의 크기를 나타낸다. 또한 각 채널파워 계산부들(211a, 211b)에서 계산된 가중치는 각각 대응하는 가중치계산부들(213a, 213b)로 출력한다.In this case, each of the channel power calculators 211a and 211b calculates a weight based on a frequency selective fading characteristic, and is a channel power for each subcarrier using channel estimates estimated by the channel equalizers 114a and 114b.

. here

Where N represents the size of the FFT. In addition, the weights calculated by the respective channel power calculators 211a and 211b are output to the corresponding weight calculators 213a and 213b, respectively.

를 추정한다.Also, the respective SNR estimators 212a and 212b of the adaptive weight calculators 210A and 210B estimate the SNR value using the channel equalization result in the channel equalizers 114a. In this case, each of the SNR estimation units 212a and 212b is an average SNR of all subcarriers of the OFDM symbol using pilot signals which are signals previously known between the transmitter and the receiver among the channel corrected data.

.

Methods of estimating the SNR include a method using correlation between pilot signals and a method using a distance between actual pilot data and demodulated pilot data. Since the method for estimating the SNR is already described in detail in a number of papers and patents, a detailed method will not be described herein. In the present invention, when estimating the SNR, any method known or used in the future may be applied.

In the above manner, the information estimated by the respective SNR estimation units 212a and 212b is provided to the corresponding weight calculators 213a and 213b, respectively.

를 계산한다. Then, each of the weight calculators 213a and 213b according to the present invention uses the SNR and the channel power within the SNR range set according to the modulation scheme to determine the weight of each antenna.

.

In this case, the SNR estimated as described above represents the quality of the entire received OFDM symbol, and the weights estimated by the channel power calculators 211a and 211b represent the quality of each subcarrier by multipath. . Therefore, by multiplying the estimated SNR by the power of the channel estimate as shown in Equation 2, weights for the MRC considering the performance of the entire OFDM symbol and the performance of the frequency selective fading characteristic can be obtained.

As such, the weights calculated by the weight calculators 213a and 213b are provided to the combining unit 131.

Therefore, the combining unit 131 corrects the output of the first receiving processor 110A by using the output of the first adaptive weight calculator 210A at the output of the first receiving processor 110A, and the second receiving processor 110A. After correcting the output of the second receiving processor 110B by using the output of the second adaptive weight calculator 210B in the output at 110B, the first receiving processor 110A and the second receiving processor 110B. The antenna diversity gain is obtained by calculating the MRC of the signal.

That is, in the combiner 131, the channel equalization result from the signals received at the antennas ANT1 and ANT2 through the reception processing units 110A and 110B and the adaptive weighting units according to the present invention ( Combining is performed using Equation 4 described above using the weights calculated in 210A and 210B.

In this case, when the number of bits representing the calculated weight increases, the amount of data transmitted from each receiver to the combining unit 131 is increased, and the hardware size of the combining unit 131 is increased. To solve this problem, each weight calculator 213a, 213b calculates the correction and weight of the estimated SNR according to the modulation scheme. As a result, the number of bits representing weights can be minimized.

3 is a control flowchart of the SNR correction and the weight calculation estimated by the modulation method in the weight calculator according to the present invention. 3 is an operation performed by both the first weight calculator 213a and the second weight calculator 213b in the same manner. Therefore, hereinafter, the first weight calculator 213a and the second weight calculator 213b will be described as the weight calculator 213 for convenience of description. In addition, the channel power calculators 211a and 211b and the SNR calculators 212a and 212b are also set as the channel power calculator 211 and the SNR calculator 212.

The weight calculator 213 acquires in advance information about a modulation scheme of a signal transmitted before the weight correction operation, that is, a signal received by each of the antennas ANT1 and ANT2, and obtains an SNR reference value according to each modulation scheme. Set in advance. As described above, the SNR reference value which is set in advance may be set differently according to the channel coding scheme and the mapping scheme, and may be set differently according to the range satisfying the performance. Examples of channel coding methods include convolution coding, low density parity check (LDPC) coding, and reed-solomon (RS) coding. Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) are used.

For ease of explanation, the system uses convolution channel coding and QAM data mapping, and the SNR reference values for the assumption that the output BER performance of Viterbi decoding for operation should be less than 10xE-6 are listed in the following table. 1>, where the SNR reference value is set to the maximum range that satisfies the output BER performance. In the SNR reference values of Table 1, dB and linear represent dB scale and linear scale, respectively, and SNR bits represent the number of bits for representing the linear scale.

As shown in Table 1, the SNR range in which the Viterbi output BER satisfies a certain performance varies depending on the channel modulation method, and the SNR reference value and the number of SNR bits can be predetermined according to the modulation method.

That is, when setting the SNR reference value according to the modulation scheme, the weight calculator 213 determines the SNR reference value and the number of bits predetermined by the modulation scheme of the signal transmitted through the channel. Thereafter, the weight calculator 213 receives the SNR estimation value and the channel power calculation value from the channel power calculator 211 and the SNR estimation 212 in operation S302.

The weight calculator 213 then checks whether the SNR estimated by the SNR estimator 212 in step S304 is greater than the SNR reference value set according to the modulation scheme. If the SNR provided in step S304 is greater than the preset SNR reference value, the process proceeds to step S308. Otherwise, the process proceeds to step S306.

In this case, when the SNR provided as a result of the check in step S304 is greater than the preset SNR reference value, that is, when the process proceeds to step S308, the situation of the channel is better than the desired performance, and thus it is not necessary to set the weight above the reference value. Therefore, the weight calculator 213 uses the SNR reference value as the corrected SNR in step S306.

On the other hand, when the SNR provided as a result of the check in step S304 is not greater than the preset SNR reference value, that is, when proceeding to step S306, the weight calculator 213 uses the estimated SNR as the corrected SNR.

Thereafter, after performing step S306 or S308, the weight calculator 213 calculates the weight by multiplying the channel power of each subcarrier by the corrected SNR as shown in Equation 2 described above in step S310. That is, the weight calculator 213 calculates the weight by multiplying the channel power calculation value received in advance in step S302 by the corrected SNR.

Thereafter, the weight calculator 213 may adjust the number of bits having a constant weight by cutting the least significant bit of the weight multiplied by the number of SNR bits set by the modulation scheme with respect to the weight calculated in step S312. That is, the weight calculator 213 cuts the least significant number of bits to reduce the data transmission amount for the MRC. As such, by reducing the amount of data transmission, it is not necessary to increase the hardware size of the combining unit 131 as in the prior art in order to obtain improved performance in all modulation schemes.

4 is a control flowchart for obtaining antenna diversity using an MRC scheme according to the present invention in an OFDM system. In the following description, the subject of each operation is assumed to be a receiver. In addition, although a plurality of antennas may be used in the present invention, it will be described on the assumption that only two antennas are used for convenience of description.

The receiver converts the radio signal received for each antenna into a baseband signal in step S400. As described above, after converting the radio signal received for each antenna into a baseband signal, the receiver synchronizes time and frequency with respect to each baseband signal in step S402. Thereafter, the receiver performs fast Fourier transform using a signal having time and frequency synchronization in step S404. Such FFT conversion is to convert a time domain signal into a frequency domain signal.

Thereafter, the receiver performs channel equalization of the symbol converted into the frequency domain signal in step S406. Such channel equalization may be performed using a symbol known in advance between the transmitter and the receiver. The symbol known in advance may be, for example, a pilot.

Thereafter, the receiver calculates the channel power using the channel equalized signal at step S408 and simultaneously calculates the SNR using a signal known in advance between the transmitter and the receiver. When the channel power and the SNR are calculated as described above, the receiver calculates the weight using the two values in step S410. Such weight calculation may be calculated as in Equation 2 described above. In addition, since the operation of the weight calculation has already been described in detail with reference to FIG. 3, the description thereof will be omitted.

Thereafter, in step S412, the receiver compensates for each antenna by using the channel equalized signal and the weight, and combines them. This process can be implemented through the process as shown in Equation 4 described above.

ANT1, ANT2: Antenna
110A, 110B: Receiver
111a, 111b: RF section
112a, 112b: synchronization unit
113a, 113b: FFT section
114a, 114b: channel equalizer
121a, 121b: Weight calculator
131: Combined part
210A, 210B: Adaptive Weight Calculator
211a and 211b: channel power calculation unit
212a, 212b: SNR estimation
213a, 213b: weight calculator

Claims (11)

An apparatus for acquiring antenna diversity using a maximum-non-coupling (MRC) technique in an orthogonal frequency division multiple access system,
A plurality of reception processing units 110A and 110B respectively configured to equalize and output the signals received through two or more antennas, respectively, and output the corresponding signals;
A plurality of adaptive weight calculators 210A and 210B for calculating symbol-to-noise ratios (SNRs) and channel powers from the signals equalized and output by the respective receivers and calculating the weights of the receivers through multiplication;
A combining unit 131 which combines the respective channel equalization signals in the respective reception processing units by using the weights of the reception processing units calculated in the adaptive weighting unit;
Antenna diversity apparatus for an orthogonal frequency division multiple access system comprising a.
The method according to claim 1,
The adaptive weight calculation unit 210A, 210B,
Channel power calculators 211a and 211b for calculating the channel power from the channel equalized signal;
SNR estimation (212a, 212b) for calculating the SNR from the channel equalized signal;
A weight calculator (213a, 213b) for calculating an adaptive weight by multiplying the channel power calculated by the channel power calculator and the SNR estimated by the SNR estimation unit;
Antenna diversity apparatus for an orthogonal frequency division multiple access system comprising a.
The method according to claim 2,
And the weight calculator (213a, 213b) is provided corresponding to each of the receiving processors (110A, 110B).
The method according to claim 3,
The weight calculation unit (213a, 213b),
The SNR reference value according to the modulation scheme is determined in advance, and compared with the estimated SNR received from the SNR estimation, if the estimated SNR value is larger than the SNR reference value, the corrected SNR is set as the reference SNR, If not, the antenna diver for an orthogonal frequency division multiple access system, characterized in that the corrected SNR is set to the estimated SNR and then multiplied by the channel power received from the channel power calculator and the corrected SNR to calculate a weight. City device.
The method of claim 4,
The weight calculation unit (213a, 213b),
Orthogonal frequency division multiple access system according to the modulation method of the received signal by cutting the number of the predetermined SNR bits from the least significant bit of the determined weight so that the weight becomes a constant bit. Diversity device for the device.
The method according to any one of claims 1 to 5,
The reception processing unit (110A, 110B),
RF units (111a, 111b) for converting the radio signal received from the antenna into a baseband signal;
A synchronization unit (112a, 112b) for outputting time and frequency synchronization of the baseband signal;
FFT units 113a and 113b for fast Fourier transforming the output of the synchronization unit;
Channel equalizers 114a and 114b for channel equalizing the output of the FFT unit using a known signal;
Antenna diversity apparatus for an orthogonal frequency division multiple access system comprising a.
A method for obtaining antenna diversity using a maximum-non-coupling (MRC) technique in an orthogonal frequency division multiple access system,
A first step of channel-equalizing and outputting a signal received through two or more antennas for each antenna;
A second step of calculating a symbol-to-noise ratio (SNR) and a channel power in each channel equalized signal and calculating a weight of a signal received for each antenna through a multiplication thereof;
A third step of combining the channel equalized signal for each antenna by using a weight calculated for each antenna;
Antenna diversity method for an orthogonal frequency division multiple access system comprising a.
The method of claim 7,
The second process,
Calculating the channel power from the channel equalized signal;
Calculating the SNR from the channel equalized signal;
Calculating a adaptive weight by multiplying the calculated channel power by the estimated SNR;
Antenna diversity method for an orthogonal frequency division multiple access system comprising a.
The method according to claim 8,
In the third step,
A step 3-1 of determining an SNR reference value according to a modulation scheme in advance;
Step 3-2 of setting the corrected SNR to the reference SNR if the estimated SNR value received from the SNR estimation is greater than a predetermined SNR reference value, and setting the corrected SNR to the estimated SNR if it is not large. ;
Step 3-3 of calculating a weight by multiplying the channel power received from the channel power calculator by a set SNR;
Antenna diversity method for an orthogonal frequency division multiple access system comprising a.
The method according to claim 9,
In the third step,
A step 3-4 of cutting the predetermined number of SNR bits from the least significant bit of the determined multiplied weight value according to a modulation scheme of the received signal with respect to the calculated weight value so that the weight becomes a constant bit;
Antenna diversity method for an orthogonal frequency division multiple access system, characterized in that it further comprises.
The method according to any one of claims 7 to 10,
The first process,
A first step of converting the radio signal received from the antenna into a baseband signal;
A first step 1-2 outputting time and frequency synchronization of the baseband signal;
A first to third step of fast Fourier transforming the output of the synchronizer;
First to fourth channel equalizing the output of the FFT unit using a known signal;
Antenna diversity method for an orthogonal frequency division multiple access system comprising a.

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