JP2007097103A - Signal separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To separately extract a signal with less computational complexity to improve frequency use efficiency under the condition that many signals are overlapped on the same frequency in a radio station in the receiving side. <P>SOLUTION: The signal separator comprises a variable frequency band-pass filter for varying the pass band by limiting the frequency band of the receiving signal, a signal parameter detecting means for detecting signal parameters of a plurality of signals included in the receiving signal, an extracting order determining means for determining the extracting order of the receiving signal from the receiving signal and signal parameter, a parameter control means for controlling pass band of the variable frequency band-pass filter from the extracted signal and signal parameter, an equalization determining means for equalizing and determining the output signal from the variable frequency band-pass filter, and a replica generating means for generating a replica of the receiving signal using an estimated value of the transmission path estimated by the determination result and equalizing process in the equalization determining means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a signal separation device used for a wireless receiver constituting a wireless communication system.

  In a wireless communication system, in order to efficiently use limited frequency resources, a technique for suppressing the amount of interference to be received is important. As a conventional technique for improving frequency utilization efficiency, there is a replica generation type interference canceller that generates a replica of a received signal as shown in FIG. 1 and effectively removes interference (see, for example, Non-Patent Document 1). .

  The replica generation type interference canceller shown in FIG. 1 sequentially estimates the transmission path of the desired signal and the interference signal using the estimation error and the reference signal by the transmission path estimation unit a, and all the symbol sequences that can be taken by the desired signal and the interference signal. By performing a convolution operation with the respective channel estimation values in the desired signal replica generator b and the interference signal replica generator c, the candidates are obtained as desired signal replicas and interference signal replicas for all symbol sequence candidates, and the sum thereof. The received signal replica is generated, the desired signal and the interference signal symbol sequence candidate that gives the closest received signal replica to the actual received signal are determined by the maximum likelihood sequence estimation unit d, and the desired signal symbol sequence candidate is received. The interference is effectively removed by outputting as the determination result. Here, as the reference signal, a known symbol series is used in the training section, and a determined symbol is used in the data section.

  In this way, by adaptively removing the interference signal from the received signal, a plurality of different signals can use the same frequency at the same time, and the frequency utilization efficiency can be improved.

  On the other hand, as another conventional technique for improving frequency utilization efficiency, a sequential multiuser detection method based on a MMSE (Minimum Mean Square Error) filter for a plurality of user signals having the same signal bandwidth as shown in FIG. Patent Document 2) has been studied.

  In the multi-user detection method based on the MMSE filter for a plurality of user signals having the same signal bandwidth shown in FIG. 2, firstly a signal to be extracted first (hereinafter, the kth extraction signal is referred to as a kth extraction target signal). The first extraction target signal is pre-estimated by the MMSE filter, and equalization processing is performed using the transmission path information of all the extraction target signals. Subsequently, based on the equalized signal, signal detection and replica generation of the first extraction target signal are performed. Next, focusing on the second extraction target signal, equalization, detection, and replica generation processing are performed. At this time, processing is performed using a signal obtained by subtracting the replica signal of the first extraction target signal from the input signal. Thereby, the second extraction target signal can be subjected to signal detection processing in a state where interference from the first extraction target signal is suppressed, and a highly reliable detection result can be obtained. In the k-th extraction target signal, signal detection processing is performed using a signal obtained by subtracting the replica signal from the first extraction target signal to the (k−1) -th extraction target signal from the input signal.

In this way, different signals use the same frequency at the same time by sequentially detecting other signals that become interference sources to the signal to be extracted, and generating and removing replicas. Thus, it is possible to improve frequency utilization efficiency.
“Proposal of separation and removal method for signals with different transmission speeds”, Proceedings of the IEICE General Conference, B-5-174, (March 2004) 'An efficient square-root algorithm for BLAST,' International conference on Acoustics, Speech, and Signal Processing (ICASSP) '00, (June 2000) 'Fractional Tap-Spacing Equalizer and Consequences for Clock Recovery in Data Modems,' IEEE Transaction on Communications, (August 1976)

  The replica generation type interference canceller shown in FIG. 1 can extract a signal by generating a replica of a signal included in a received signal. However, as the number of signals handled increases, the amount of calculation increases exponentially. There is a problem that it is difficult to complete the processing in a certain calculation time. In particular, when a plurality of narrowband signals are superimposed and transmitted on the same frequency as the wideband signal, a large number of narrowband signals must be processed at the same time in order to separate and extract the wideband signal. It becomes difficult to separate and extract the.

  In addition, the multi-user detection method based on the MMSE filter for a plurality of user signals having the same signal bandwidth shown in FIG. 2 performs signal equalization using the channel information of the interference signal in the MMSE filter. The accuracy and the replica generation accuracy can be kept high. At this time, generally, the transmission path information uses a value estimated on the receiver side. However, when signals with different signal bandwidths are superimposed on the same frequency in the received signal, each signal is band-limited by a filter (not shown) having a different pass band from the transmission side. The signal is affected by inter-symbol interference (ISI). Regarding this ISI, the signal to be extracted included in the received signal itself is the same in the environment where there is no delayed wave because the signal bandwidth of the band limiting filter on the transmitting side and the band limiting filter on the receiving side are the same. It is possible to prevent ISI from occurring by using a band-limiting filter. However, for signals of other users whose signal bandwidth is different from the extraction target signal, the reception signal is band-limited by the reception-side band limiting filter for the extraction target signal. Therefore, the signal bandwidths of the band-limiting filters are different, resulting in ISI. This ISI varies greatly depending on the sample timing, and the state of the transmission path also varies greatly at each sample timing. Such fluctuations can be estimated by performing transmission path estimation using a fractionally spaced coefficient variable filter (Non-patent Document 3), but the number of filter taps is extremely large, resulting in an increase in the amount of calculation and transmission. The path estimation accuracy is degraded.

  The present invention has been made to solve the above-mentioned conventional problems, and enables separation and extraction of signals with a small amount of calculation under the condition that a large number of signals overlap on the same frequency. An object of the present invention is to provide a signal separation device capable of improving frequency utilization efficiency.

  In order to solve the above-described problems, in the present invention, as described in claim 1, a plurality of transmission-side radio stations and a plurality of reception-side radio stations having different signal bandwidths and carrier frequencies of transmission signals In the wireless communication system that performs communication by transmitting a wireless signal from the transmitting wireless station to the receiving wireless station that is a communication counterpart, the signal separating device is provided in the receiving wireless station. A bandpass filter that can limit the band of the received signal and vary the passband, signal parameter detection means for detecting signal parameters of a plurality of signals included in the received signal, and the received signal Extraction order determination means for determining the extraction order of received signals from the signal parameters extracted by the signal parameter detection means, and extraction order determined by the extraction order determination means Parameter control means for controlling the passband of the passband variable bandpass filter from signal parameters extracted by the signal parameter detection means, and equalization and determination of the output signal from the passband variable bandpass filter A replica generation unit configured to generate a replica of the received signal using a determination unit and a determination result in the equalization determination unit and a transmission path estimation value estimated in the equalization process, and included in the received signal Using the difference in signal parameters of the plurality of signals, and sequentially separating and extracting the plurality of signals from the received signal by the passband variable bandpass filter and equalization determining means according to the extraction order. Yes. By adopting such a configuration, when various types of signals share the frequency band, it is possible to separate and extract the signals included in the received signal with a small amount of processing on the receiving side. It becomes.

  In addition, as described in claim 2, the signal separation device according to claim 1, wherein the extraction order determination means includes a plurality of signals included in the received signal from the received signal and the signal parameter. Using the mutual interference amount estimation means for estimating the mutual interference amount when the signals of the two signals interfere with each other, and the estimated mutual interference amount estimated by the mutual interference amount estimation means, from the received signal to the received signal. Quality estimation and rank determination means for determining a rank for separating and extracting the included signals, and the quality estimation and rank determination means has a quality as a reference when determining a signal of a predetermined extraction rank. It is possible to calculate the estimated mutual interference amount to other signals due to the signal having the extraction order before the predetermined extraction order as a predetermined value or less and determine the order. Thereby, it becomes possible to extract in order from a signal with high quality.

  In addition, as described in claim 3, the signal separation device according to claim 2, wherein the mutual interference amount estimation unit estimates a reception power of a plurality of signals included in the reception signal. A unit of each of a plurality of signals included in the received signal from power estimation means, the signal parameter, and a power estimation value of each of the plurality of signals included in the received signal estimated by the signal power estimation means Based on the power calculation means for calculating the power per bandwidth and the signal parameters, the bandwidth of the frequency at which the plurality of signals included in the received signal overlap and interfere with each other is estimated. Signal power per unit bandwidth of each of a plurality of signals included in the received signal, calculated by the signal superimposition state estimating means and the power per unit bandwidth calculating means Interference power calculation means for calculating an estimated mutual interference amount from a calculated value and a superimposed frequency bandwidth of a plurality of signals included in the received signal estimated by the signal superposition state estimation means It can be. This makes it possible to easily estimate the amount of interference between a plurality of signals included in the received signal.

  In addition, as described in claim 4, the signal separation device according to claim 3, wherein the mutual interference amount estimation unit uses the received signal and the signal parameter to include the received signal in the received signal. Comprising a transmission path estimation means for estimating a transmission path estimation value that is a state of a transmission path with a time spread of a plurality of signals included, wherein the signal power estimation means includes each signal estimated by the transmission path estimation means The power can be estimated using the transmission path estimation value for the main wave. This makes it possible to estimate the power of each signal with high accuracy.

  In addition, as described in claim 5, the signal separation apparatus according to claim 3, wherein the signal power estimation means is a known symbol sequence corresponding to each of a plurality of signals included in the received signal. By performing correlation detection using, the power of each signal can be estimated. This makes it possible to estimate the power of each signal with a simple configuration.

  In addition, as described in claim 6, the signal separation device according to claim 3, wherein the power calculation unit per unit bandwidth is a signal of each signal for a predetermined time by the signal power estimation unit. The signal power per unit bandwidth of each signal can be calculated by averaging the estimated power value with the signal bandwidth included in the signal parameter of each signal. This makes it possible to estimate the amount of interference per unit bandwidth that each signal gives to other signals.

  In addition, as described in claim 7, in the signal separation device according to claim 3, the signal superimposition state estimation unit is configured to calculate from the center frequency information and the signal bandwidth information included in the signal parameter. The upper and lower limits of the frequency band used for each signal are calculated, and the upper and lower limits of the calculated frequency band are compared among all the signals included in the received signal, and the superimposed frequency between the signals is calculated. The bandwidth can be calculated. This makes it possible to obtain a signal band in which the signals interfere with each other with a simple calculation.

  Further, as described in claim 8, in the signal separation device according to claim 3, the interference power calculation unit is configured to calculate per unit bandwidth of each signal obtained by the power calculation unit per unit bandwidth. The interference power between a plurality of signals included in the received signal is calculated by multiplying the signal power by the superimposed frequency bandwidth between the signals obtained by the signal superposition state estimating means. it can. As a result, it is possible to estimate the interference power between the signals with a simple calculation.

  The signal separation device according to any one of claims 1 to 3, wherein the extraction order determining means is included in the received signal from the received signal and the signal parameter. A plurality of signals included in the received signal from a mutual interference amount estimating means for estimating a mutual interference amount when the plurality of signals overlap on the frequency axis and interfere with each other, and the received signal and the signal parameter Using the noise estimation means for estimating the noise power received by each of the signals, the estimated mutual interference amount estimated by the mutual interference amount estimation means, and the estimated noise power estimated by the noise estimation means, Quality estimation and rank determination means for determining a rank for separating and extracting signals included in the received signal from the signal, and the quality estimation and rank determination means is a signal having a predetermined extraction rank. Decision criteria become quality extraction rank than the predetermined extraction rank when calculates the estimated mutual interference amount to other signals by the signal before the predetermined value or less, it can be made to determine the ranking. As a result, the extraction order can be determined using the communication quality in consideration of the noise included in the received signal, and the signal can be separated and extracted with high accuracy.

  The signal separation device according to claim 9, wherein the noise estimation unit generates a replica of the received signal from the received signal and the signal parameter. Generating means, a subtractor for subtracting the replica signal generated by the replica signal generating means from the received signal, and outputting a residual signal; and the residual signal, each of a plurality of signals included in the received signal A band-pass filter that limits the bandwidth with the signal bandwidth, and a noise power estimation means that calculates the power of the noise band-limited by the band-pass filter, and estimates a noise signal waveform included in the received signal By limiting the frequency band, the power of noise that affects a plurality of signals included in the received signal can be obtained and output for each signal. This makes it possible to easily obtain the noise power that affects each signal included in the received signal.

  In addition, as described in claim 11, in the signal separation device according to claims 1 to 10, the extraction order determination means sets a higher extraction order as communication quality is higher. it can. As a result, it is possible to reduce determination errors in signals with higher extraction ranks, and to separate and extract signals with high accuracy.

  Further, as described in claim 12, in the signal separation device according to claims 1 to 11, using the passband variable bandpass filter, the equalization determination unit, and the replica generation unit, There are multiple stages that output replica signals of each signal included in the received signal, and at a given stage, the replica signal generated in the previous stage is subtracted from the received signal, and the result is used to limit the bandwidth, etc. It is possible to make a determination. By performing iterative equalization using multiple stages in this way, it is possible to obtain a highly accurate transmission path estimation value, and each signal included in the received signal is separated and extracted with high accuracy. Is possible.

  The signal separation device according to any one of claims 1 to 12, wherein the signal parameter detecting means estimates a signal parameter of each signal included in the received signal from the received signal. And can be detected. As a result, signal separation can be performed in a state where there is no information regarding each signal in advance.

  In addition, as described in claim 14, in the signal separation device according to claims 1 to 13, the signal parameter detection unit is notified in advance of signal parameters of each signal from a radio station on the transmission side. Can be. As described above, by obtaining the signal parameters of each signal in advance, the signal separation operation can be easily performed.

  In addition, as described in claim 15, there are a plurality of wireless transmitters having different signal bandwidths of transmission signals and a single wireless receiver including a multi-user detector, and the wireless reception from the wireless transmitter In a wireless communication system for performing communication by transmitting a wireless signal to a device, the signal separation device is provided in the wireless receiver, wherein the multi-user detector is configured to transmit signals from the plurality of wireless transmitters. Correspondingly, a band limiting filter having a different pass band and a code used by the plurality of radio transmitters using the signal information and having a different pass band for each user and a code generated by the filter in the radio receiver A transmission line calculation unit that calculates the state of the transmission line in consideration of interference, the transmission line state calculated by the transmission line calculation unit, and the filter information using the signal information. MMSE filter for equalizing the band limited signal in the band limiting filter using the replica of the symbol sequence mapped on the signal space estimated in the replica generator, and equalized by the MMSE filter A soft input / output decoder for determining received data of each user using a signal in consideration of the signal information, and calculating a likelihood of a symbol mapped on the signal space; and the soft input / output decoding A symbol sequence replica of the signal mapped in the signal space is generated from the likelihood of the symbol calculated by the transmitter and input to the MMSE filter, and the influence of the transmission path is determined using the generated symbol sequence replica and the signal information. A replica generator that generates a received signal replica in consideration and a signal input to the multi-user detector in the replica generator. The generated received signal replicas can be made and a subtracter for subtracting. As a result, it is possible to perform equalization processing in consideration of large fluctuations in ISI due to filters of signals having different signal bandwidths, and signals can be separated with high accuracy.

  In addition, as described in claim 16, the signal separation device according to claim 15, wherein the radio receiver is obtained by cascading a plurality of the multi-user detection units. In the multi-stage multi-user detection unit, the multi-user detection unit may perform signal detection and replica generation using a replica signal generated in the multi-user detection unit in the previous stage of the cascade connection. . As a result, the accuracy of replica generation can be improved and signals can be separated with higher accuracy.

  According to the signal separation device of the present invention, it is possible to separate and extract signals with a small amount of calculation under the condition that a plurality of signals having different signal parameters share the same frequency and perform communication.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 3 is a block diagram illustrating a configuration example of a receiver including the signal separation device according to the first embodiment of the present invention. FIG. 4 shows a conceptual diagram of a signal processing process of the signal separation device.

In FIG. 3, the receiver 10 limits the band of a received signal and can change the pass band, and a variable band-pass filter 11 (11 ₁ , 11 ₂ ) and a plurality of signals included in the received signal. Signal parameter detection means 12 for detecting parameters, extraction order determination means 13 for determining the extraction order of received signals from the received signals and the signal parameters extracted by the signal parameter detection means 12, and extraction order determination means 13 The parameter control means 14 for controlling the pass band of the pass band variable band pass filter 11 from the extracted extraction order and the signal parameter extracted by the signal parameter detection means 12, and the output signal from the pass band variable band pass filter 11 are equalized And the equalization determination means 15 (15 ₁ , 15 ₂ ) to be determined, the determination result in the equalization determination means 15 and the transmission path estimation value estimated in the equalization It comprises replica generating means 16 for generating a replica of the received signal and a subtractor 17 for subtracting the replica signal from the received signal.

Signals having different transmission signal parameters are transmitted from the transmitter 1 and the transmitter 2, respectively, and the receiver 10 receives a reception signal A obtained by adding these signals. The received signal A is input to the passband variable bandpass filter 11 ₁ , the extraction order determining means 13 and the subtractor 17. Further, the parameters of the transmission signal such as the signal bandwidth, the center frequency, and the modulation method of the signal 1 and the signal 2 are notified to the signal parameter detection unit 12 of the receiver 10 prior to communication. As an example, the signal parameter is notified prior to the start of communication by a radio control signal using a common radio channel. Here, an example in which notification is given prior to the start of communication is shown.

The signal parameter detection unit 12 detects the signal parameters of the signal 1 and the signal 2 included in the received signal and inputs them to the extraction order determination unit 13 and the parameter control unit 14. The extraction order determining means 13 determines the order of extracting signals (signal 1 and signal 2) included in the received signal from the received signal A and the signal parameter B, and inputs the extraction order C to the parameter control means 14. The parameter control means 14 determines the passband variable bandpass filter # 1 (11 ₁ ) so that the signal with the highest extraction order is passed from the information on the center frequency and signal bandwidth detected by the signal parameter detection means 12. Similarly, the passband is controlled, and parameters necessary for equalization and determination, such as the modulation scheme and symbol rate of the signal with the highest extraction order, are input to equalization determination means # 1 (15 ₁ ). Similarly, the passband variable bandpass filter # 2 (11 ₂ ) and equalization determination means # 2 (15 ₂ ) are controlled using the signal parameters of the signal with the second extraction order.

The signal that has passed through the passband variable bandpass filter # 1 (11 ₁ ) is a signal component in a frequency band other than the frequency band of the signal with the highest extraction order, as indicated by the signal G after band limitation in FIG. Becomes a suppressed signal. The band-limited signal G is input to equalization determination means # 1 (15 ₁ ) to perform equalization and determination. At this time, the determination result # 1 (D ₁ ) and the transmission path estimation value E obtained in the equalization process are input to the replica generation means 16. The replica generation means 16 generates a replica signal F of the signal ranked first in the extraction order from the determination result # 1 (D ₁ ) and the transmission path estimation value E, and inputs the replica signal to the subtracter 17. The subtractor 17 subtracts the replica signal F from the received signal A and inputs the result to the passband variable bandpass filter # 2 (11 ₂ ). At this time, the signal input to the passband variable bandpass filter # 2 (11 ₂ ) is obtained by subtracting the signal having the highest extraction order from the received signal, as indicated by the signal H after the extraction target signal is removed in FIG. That is, the extracted signal, that is, the signal having the second extraction order and the signal consisting of noise. The pass band variable band pass filter # 2 (11 ₂ ) varies the pass band so as to pass the signal of the second extraction order specified by the parameter control means 14, and the output of the filter is equalized by the judgment means # 2 ( 15 Enter in ₂ ). The equalization determination means # 2 (15 ₂ ) equalizes and determines the second extraction order signal from the input signal, and outputs a determination result # 2 (D ₂ ).

  By doing this, it is possible to perform the determination in a state where the amount of interference received from the signal of the extraction order first is small, under the condition that the signal of the extraction order first can be correctly determined. Therefore, it is possible to separate and extract the signal included in the reception signal A with high accuracy.

<Second Embodiment>
FIG. 5 is a block diagram showing a configuration example of a receiver including a signal separation device according to the second exemplary embodiment of the present invention. The configuration in the case where there are two transmitters in the first exemplary embodiment shown in FIG. The example is extended when there are K transmitters from 1 to K. Functional blocks that operate in the same manner as in FIG. 3 will be assigned the same reference numerals and description thereof will be omitted.

At receiver 10, the bandpass tunable bandpass filter _{11 (11 1, 11 2,} ~, 11 K) and the equalization judging means _{15 (15 1, 15 2,} ~, 15 K) K number of each replica generating means 16 (16 ₁ , 16 ₂ ,..., 16 _K-1 ) and _K-1 subtractors 17 (17 ₁ , 17 ₂ ,..., 17 _K-1 ). Passband variable bandpass filter # 1 (11 ₁ ) is the first extraction order signal, passband variable bandpass filter # 2 (11 ₂ ) is the second extraction order signal, and passband variable bandpass filter # K (11 _K ) varies the pass band of the filter so that signals of the extraction rank K are passed through. The signals that have passed through the passband variable bandpass filters # 1, # 2,..., #K are input to equalization determination means # 1, # 2,. Equalization determining means # 1, # 2,..., #K equalize and determine the input signal, and determine the transmission path estimation values E ₁ , E ₂ ,. D ₁ , D ₂ ,... Are input to replica generation means # 1, # 2,. The replica generation means # 1, # 2,... Generate replicas of extraction order signals 1, 2,..., Respectively, and input them to the subtracters 17 ₁ , 17 ₂ ,. The subtractor # 1 (17 ₁ ) subtracts the replica signal F ₁ of the extraction rank first signal from the received signal A, and the subtraction result is passed through the passband variable bandpass filter # 2 (11 ₂ ) and the subtractor # 2 ( 17 Input to ₂ ). The subtracter # 2 (17 ₂ ) subtracts the replica signal F ₂ of the second extraction rank signal from the signal input from the subtractor # 1, and the subtraction result is the passband variable bandpass filter of the next stage. And input to the subtractor. In this way, by removing from the received signal in order from the signal with the highest extraction order, the signal input to the passband variable bandpass filter at a predetermined stage has a higher extraction order than the signal to be passed by the filter. A signal replica signal is subtracted, and the signal can be separated and extracted with high accuracy.

  FIG. 6 is a block diagram showing an example of the configuration of the extraction order determination means 13, which is composed of a mutual interference amount estimation means 131 and a quality estimation and order determination means 132.

  The mutual interference amount estimating means 131 estimates a mutual interference amount (estimated mutual interference amount I) between a plurality of signals included in the received signal from the received signal A and the signal parameter B, and performs quality estimation and rank determining means 132. To enter. Here, the estimated mutual interference amount I is expressed by Equation 1 below, where I (a, b) is an estimated value of the interference amount that the signal a gives to the signal b. The interference amount estimated value I (a, a) is the power of the signal a.

図７は図６の品質推定及び順位決定手段132の動作を表すフローチャートである。品質推定及び順位決定手段132は、図７のフローに従って抽出順位を決定する。

FIG. 7 is a flowchart showing the operation of the quality estimation and rank determination means 132 of FIG. The quality estimation and rank determination means 132 determines the extraction rank according to the flow of FIG.

First, the extraction order i is set to “1” as an initial setting (step S10). Subsequently, it is determined whether i is equal to the number of signals included in the received signal (step S11). If they are not equal, the process proceeds to step S12. If they are equal, the process ends. In step S12, the communication quality of each signal is estimated using the estimated mutual interference amount estimated by the mutual interference amount estimating means 131. Then, a desired signal power to interference signal power ratio SIR _est corresponding to each signal included in the received signal is calculated by the following formula 2, and the one having the highest value is set as the extraction order i (step S13).

続いて、ステップS13において最も品質の良かった信号が他の信号へ与える干渉量と、その信号自身の希望信号電力を全て‘0’にする（ステップS14）。なお、ここでは電力を‘0’としたが、レプリカ信号の生成誤差から信号を完全に除去することが困難である条件を考慮して、微小な値に設定するのであっても良い。続いて、抽出順位iを1増加し、i+1 にし（ステップS15）、ステップS11に戻る。

Subsequently, the amount of interference given to the other signal by the signal having the best quality in step S13 and the desired signal power of the signal itself are all set to “0” (step S14). Although the power is set to “0” here, it may be set to a minute value in consideration of the condition that it is difficult to completely remove the signal from the generation error of the replica signal. Subsequently, the extraction order i is incremented by 1 to i + 1 (step S15), and the process returns to step S11.

  The extraction order is determined by the above operation. In this way, it is possible to extract in order from a signal that is less affected by interference and is expected to have good communication quality.

FIG. 8 is a block diagram showing another configuration example of the extraction order determination means 13. In FIG. 8, the extraction order determination means 13 includes a mutual interference amount estimation means 131, a quality estimation and rank determination means 133, and an (E _b / I _o ) -BER correspondence table 134. FIG. 9 shows a flowchart of the operation of the quality estimation and rank determination means 133.

  The mutual interference amount estimating means 131 estimates a mutual interference amount (estimated mutual interference amount I) between a plurality of signals included in the received signal from the received signal A and the signal parameter B, and performs quality estimation and rank determining means. Input to 133.

The quality estimation and rank determination means 133 operates according to the flowchart of FIG. That is, the extraction order i is set to “1” as an initial setting (step S20). Subsequently, it is determined whether i is equal to the number (K) of signals included in the received signal (step S21). If they are not equal, the process proceeds to step S22. If they are equal, the process ends. In step S22, the signal power to interference power ratio (E _b / I _o ) per bit is estimated from the estimated mutual interference amount I and the modulation scheme information X included in the signal parameter B. Subsequently, from the estimated E _b / I _o (Y) and modulation scheme information X, with reference to the (E _b / I _o ) -BER correspondence table 134, estimated bits of each signal included in the received signal A The error rate [BER (1), BER (2),..., BER (K)] Z is obtained (step S23). Here, BER (p) is an estimated bit error rate of the signal p. Next, the extraction order of the signal with the lowest estimated bit error rate is set to 'i' (step S24), and the amount of interference that the signal of the extraction order 'i' gives to other signals and the desired signal power of the signal itself are all Set to '0' (step S25). Although the power is set to “0” here, it may be set to a minute value in consideration of the condition that it is difficult to completely remove the signal from the generation error of the replica signal. Subsequently, the extraction order i is incremented by 1 to i + 1 (step S26), and the process returns to step S21.
The extraction order is determined by the above operation. With such a configuration, it is possible to sequentially extract signals that are expected to have a low bit error rate, and it is possible to separate and extract signals included in the received signal A with high accuracy.

  FIG. 10 is a block diagram showing a configuration example of the mutual interference amount estimating means 131. The transmission path estimating means 1311, the signal power estimating means 1312, the power calculating means 1313 per unit bandwidth, the signal superposition state estimating means 1314, Interference power calculation means 1315.

  The transmission path estimation means 1311 estimates transmission paths of a plurality of signals included in the received signal A, and the estimated transmission path estimation value J is input to the signal power estimation means 1312. Here, a training sequence of signal parameters is input to transmission path estimation means 1311 and used, but a transmission path may be estimated using pilot symbols. The signal power estimation means 1312 estimates the power of each signal from the input transmission path estimation value J.

  Also, as shown in FIG. 11, the transmission path estimation means 1311 of FIG. 10 is omitted, and the signal power estimation means 1312 uses a known symbol string for the received signal A in the correlation detector 13121 (a training sequence as an example in FIG. 11). The power of each signal can be estimated from the correlation value detected by the correlation detector 13121 in the power estimation means 13122.

10 and 11, the power estimation value L of each signal is input to the power calculation unit 1313 per unit bandwidth, and the power calculation unit 1313 per unit bandwidth uses the information on the signal bandwidth. The signal power per unit bandwidth is calculated, and the calculation result is input to the interference power calculation means 1315. Here, the power per unit bandwidth of the signal p is W _U (p). At this time, as shown in FIG. 12, the power calculation unit 1313 per unit bandwidth time-integrates the instantaneous value P (t) of the power of each signal estimated by the signal power estimation unit 1312 and averages it with the observation time. Then, the power per unit time is obtained and divided by the signal bandwidth information BW in the signal parameter B to obtain the calculated signal power per unit bandwidth. At this time, a signal power calculation value per unit bandwidth of the signal p is obtained by the following Equation 3.

ここで、図１３に各信号の電力と単位帯域幅あたりの信号電力との関係例を示す。図１３は、信号１（A₁）と信号2（A₂）と信号3（A₃）の3つの信号が重畳して受信されている例を示しており、各信号の電力は、それぞれの信号を表す領域の面積となる。また、単位帯域幅あたりの電力は、概ね図中の各信号を表す領域の高さとなる。なお、1ビットあたりの電力は、単位帯域幅あたりの電力を、単位帯域幅あたりの送信可能ビット数で割り算した結果となる。

FIG. 13 shows an example of the relationship between the power of each signal and the signal power per unit bandwidth. FIG. 13 shows an example in which _three signals of signal 1 (A ₁ ), signal 2 (A ₂ ), and signal 3 (A ₃ ) are received in a superimposed manner. This is the area of the region representing the signal. Further, the power per unit bandwidth is approximately the height of the area representing each signal in the figure. Note that the power per bit is the result of dividing the power per unit bandwidth by the number of transmittable bits per unit bandwidth.

The signal superimposition state estimation means 1314 calculates the bandwidth of the frequency at which the signals included in the received signal A overlap each other from the center frequency and the signal bandwidth information, and sends the calculated value to the interference power calculation means 1315. input. Here, a frequency bandwidth in which the signal p is superimposed on the signal q is B _overlay (p, q).

This will be described with reference to FIG. Here, the area O ₁ where signal 1 and signal 2 overlap (interfering area) is at the left end of the frequency band of signal 1, and the width of this overlapping band is defined as B _overlay (1,2) And At this time, the formula B _overlay (1,2) = B _overlay (2,1) is established. Further, the bandwidth in which the signal p overlaps the signal p, that is, the signal bandwidth of the signal p is represented by B _overlay (p, p). At this time, since the region O ₂ where the signal 1 and the signal 3 overlap is equal to the band of the signal 3, B _overlay (1,3) = B _overlay (3,1) = B _overlay (3,3) Become. Further, since the signal 2 and signal 3 region O ₃ which overlap does not exist, B _overlay (2,3) = a B _overlay (3,2) = 0. Note that the superimposed frequency bandwidth is divided into cases as shown in FIG. 14 based on the center frequency and the signal bandwidth, and is obtained by the following equations 4 to 7. Here, the center frequencies of the signals p and q are f _cp and f _cq , respectively, and the signal bandwidths are BW _p and BW _q , respectively. Further, the signal p and the signal q can be arbitrary signals included in the received signal, and the following equation can be applied by exchanging the signal p and the signal q.
(a) when the use frequency band of the signal p is encompasses the use frequency band of the signal q (i.e. _{f cq + BW q / 2 ≦} f cp + BW p / 2 and _{f cp -BW p / 2 ≦ f} cq -When BW _q / 2)

(b) 信号pの使用周波数帯域の上限が信号qの使用周波数帯域内に存在している場合
（すなわちf_cp+BW_p/2≦f_cq+BW_q/2かつf_cp-BW_p/2≦f_cq-BW_q/2であるとき）

(b) When the upper limit of the use frequency band of the signal p exists within the use frequency band of the signal q (that is, f _cp + BW _p / 2 ≦ f _cq + BW _q / 2 and f _cp -BW _p / 2 ≦ when f is _cq -BW _q / 2)

(c) 信号pの使用周波数帯域の下限が信号qの使用周波数帯域内に存在している場合
（すなわちf_cq+BW_q/2≦f_cp+BW_p/2かつf_cq-BW_q/2≦f_cp-BW_p/2であるとき）

(c) if the lower limit of the frequency band of the signal p is present in the frequency band of the signal q (i.e. _{f cq + BW q / 2 ≦} f cp + BW p / 2 and f _cq -BW _q / 2 ≤ f _cp -BW _p / 2)

(d) 信号pの使用周波数帯域が信号qの使用周波数帯域と重ならない場合
（すなわちf_cq+BW_q/2≦f_cp-BW_p/2またはf_cp+BW_p/2≦f_cq-BW_q/2であるとき）

(d) if the use frequency band of the signal p does not overlap the frequency band of the signal q (i.e. _{f cq + BW q / 2 ≦} f cp -BW p / 2 or _{f cp + BW p / 2 ≦} f cq -BW _q / 2)

干渉電力計算手段1315では、入力された、各信号の単位帯域幅あたりの信号電力計算値M及び複数の信号同士の重畳周波数帯域幅Oとから、推定相互干渉量Iを計算する。このとき、信号qが信号pから受ける干渉量は、信号pの単位帯域幅あたりの電力を、信号pと信号qの重畳している周波数帯域幅に乗算することにより得られる。即ち、推定相互干渉量I(p,q)は、下記数式8により計算される。

The interference power calculation means 1315 calculates the estimated mutual interference amount I from the input signal power calculation value M per unit bandwidth of each signal and the superimposed frequency bandwidth O of a plurality of signals. At this time, the amount of interference that the signal q receives from the signal p is obtained by multiplying the power per unit bandwidth of the signal p by the frequency bandwidth in which the signal p and the signal q are superimposed. That is, the estimated mutual interference amount I (p, q) is calculated by the following formula 8.

図１５に相互干渉量の概念図を示す。信号2から信号1へ干渉する信号の部分は図中Pの領域で表され、この領域の電力は概ねＷ_U(2)B_overlay(2,1)=I(2,1)となる。また、信号3から信号1へ干渉する信号の部分は図中のQの領域で表され、この領域の電力は概ねＷ_U(3)B_overlay(3,1)=I(3,1)となる。つまり、信号1が受ける総干渉量は、I(2,1)+I(3,1)となる。このとき、信号1の電力は、Ｗ_U(1)B_overlay(1,1)=I(1,1)であるから、信号1の推定通信品質（この場合は推定SIR）は、下記の数式9により表される。

FIG. 15 shows a conceptual diagram of the mutual interference amount. The portion of the signal that interferes with signal 1 from signal 2 is represented by the area P in the figure, and the power in this area is approximately W _U (2) B _overlay (2,1) = I (2,1). In addition, the portion of the signal that interferes from signal 3 to signal 1 is represented by the Q region in the figure, and the power in this region is approximately W _U (3) B _overlay (3,1) = I (3,1). Become. That is, the total amount of interference received by signal 1 is I (2,1) + I (3,1). At this time, since the power of signal 1 is W _U (1) B _overlay (1,1) = I (1,1), the estimated communication quality of signal 1 (in this case, estimated SIR) is Represented by 9.

同様に信号2、信号3についても推定通信品質を容易に求めることが可能となる。

Similarly, the estimated communication quality can be easily obtained for the signals 2 and 3.

  Note that the signal demultiplexer in FIG. 3 may be configured to use the transmission path estimation value J obtained in FIG.

  FIG. 16 is a block diagram illustrating a configuration example of the extraction order determination unit 13 when a signal to be communicated using a spread code is included in the received signal. FIG. 17 is a flowchart showing the operation of the quality estimation and rank determination means 132 in FIG.

  In FIG. 16, the mutual interference amount estimation unit 131 obtains the estimated mutual interference amount I in the same manner as in FIG. 6, but at this time, using the spreading factor information R input as the signal parameter B, the signal power I (p , p) is set to a value SF (p) I (p, p) obtained by multiplying the spreading factor SF (p). In this configuration, it is possible to cope with a signal that does not use a spreading code by setting the spreading factor information to ‘1’. At this time, the desired signal power to interference signal power ratio in the communication quality comparison (step S32) in the operation flow of FIG.

として計算されるため、拡散利得を考慮して抽出順位を定めることができるようになる。このようにすることにより、拡散符号を使用する信号と使用しない信号とが混在している受信信号に対しても、効果的に抽出順位を定めることが可能となり、高精度に信号を分離して取り出すことが可能となる。

Therefore, the extraction order can be determined in consideration of the diffusion gain. In this way, it is possible to effectively determine the extraction order even for a received signal in which a signal using a spreading code and a signal not using it are mixed, and the signal is separated with high accuracy. It can be taken out.

  FIG. 18 is a block diagram showing another configuration example of the extraction order determination means 13. This configuration diagram is obtained by adding a noise estimation unit 135 to the extraction order determination unit 13 of FIG. 6, and there is no difference in operation with respect to the other parts, so the description thereof will be omitted.

  The mutual interference amount estimation means 131 estimates the mutual interference amount of a plurality of signals included in the reception signal A from the reception signal A and the signal parameter B, and sends the estimated mutual interference amount I to the quality estimation and rank determination means 132. input. Noise estimation means 135 estimates the noise power received by each of a plurality of signals included in reception signal A from reception signal A and signal parameter B, and inputs estimated noise power T to quality estimation and rank determination means 132 . The quality estimation and rank determining means 132 determines the extraction rank according to the operation flow of FIG. 19 from the input estimated mutual interference amount I and estimated noise power T. The operation flow in FIG. 19 is the same as the operation flow in FIG. 7, and there is a difference only in whether or not noise is considered in the communication quality that is the order determination criterion. Specifically, first, as an initial setting, the extraction order i is set to ‘1’ (step S40). Subsequently, it is determined whether i is equal to the number of signals included in the received signal (step S41). If they are not equal, the process proceeds to step S42, and if they are equal, the process is terminated. In step S42, the signal power to interference signal power plus noise power ratio of each of the plurality of signals included in the received signal A is obtained, and the one having the highest ratio is set as the extraction order i. Subsequently, in step S42, it is assumed that the power of the signal having the best quality becomes “0”. That is, the amount of interference that the signal gives to other signals and the desired signal power of the signal itself are all set to '0' (step S43). Subsequently, the extraction order i is incremented by 1 to i + 1 (step S44), and the process returns to step S41. In this way, when multiple signals with different signal bandwidths use overlapping frequency bands, it is possible to estimate the effects of noise on each signal with high accuracy and extract them effectively. It becomes possible to set the ranking.

Note that, by using the influence of noise obtained in this embodiment, signal power versus interference and noise power E _b / (I ₀ + N ₀ ) per bit are calculated in the same manner as in FIG. The estimated bit error rate may be used to determine the extraction order based on the estimated bit error rate.

FIG. 20 is a block diagram illustrating a configuration example of the noise estimation unit 135, which includes a replica signal generation unit 1351, a subtractor 1352, a bandpass filter 1353 (1353 ₁ , 1353 ₂ ,..., 1353 _k ), noise power, and the like. Estimation means 1354. FIG. 21 shows a conceptual diagram of the operation of the noise estimation means 135.

The replica signal generating means 1351 generates a replica of a plurality of signals included in the received signal A from the received signal A and the training sequence in the signal parameter B, and outputs a received signal replica U that is the sum of the replicas. Input to the subtractor 1352. The subtracter 1352 subtracts the received signal replica U from the received signal A. In this way, by subtracting the received signal replica U from the input signal A, only the noise component remains and the residual signal V can be obtained. Subsequently, the residual signal V is input to the band pass filter 1353. The band pass filter 1353 limits the band of the residual signal V in accordance with the frequency bands of a plurality of signals included in the received signal. Specifically, the noise after passing through the band-pass filter is expressed by the following formula when the Fourier transform of the residual signal is N (f) and the band-pass filter 1353 _p corresponding to the signal _p is H _p (f). 11 (N _H (p, f)) as an inverse Fourier transform.

ただし、H_p(f)は、通過帯域を信号pの使用帯域（すなわち、f_cp-BW_p/2≦f≦f_cp+BW_p/2）とするものである。このとき、図２１に示されるように、帯域通過フィルタ1353からは受信信号Aに含まれる各信号の周波数帯域に応じて帯域制限された雑音W(W₁,W₂,W₃)が出力される。このようにすることにより、図３の通過帯域可変帯域通過フィルタ11を通過させた後に残留する雑音成分を推定することができる。出力された帯域制限された雑音Wは、雑音電力推定手段1354に入力され、雑音電力推定手段1354は受信信号A中に含まれる各信号が受ける雑音の電力を下記の数式を用いて推定してその結果を出力する。

However, H _p (f) has a pass band as a use band of the signal p (that is, f _cp −BW _p / 2 ≦ f ≦ f _cp + BW _p / 2). At this time, as shown in FIG. 21, the bandpass filter 1353 outputs noise W (W ₁ , W ₂ , W ₃ ) band-limited according to the frequency band of each signal included in the received signal A. The By doing so, it is possible to estimate a noise component remaining after passing through the passband variable bandpass filter 11 of FIG. The output band-limited noise W is input to the noise power estimation unit 1354, which estimates the noise power received by each signal included in the received signal A using the following equation. The result is output.

以上により、受信信号A中に含まれる雑音と、各信号がそれぞれ受ける雑音電力を推定することができる。

As described above, it is possible to estimate the noise included in the received signal A and the noise power received by each signal.

<Third Embodiment>
FIG. 22 is a block diagram illustrating a configuration example of a receiver including a signal separation device according to the third embodiment of the present invention. As described above, the present invention may be configured such that the error correction decoder 151 (151 ₁ , 151 ₂ ) and the error correction encoder 152 are added. In this case, the output of the equalization determination means # 1 is input to the error correction decoder 151 _1, performs decoding in accordance with the error correction coding method the sent as a transmission signal parameter, the result determines the result # 1 (D ₁ ) is output. Determination result # 1 (D ₁ ) is input to error correction encoder 152, encoded by the same encoding method as that on the transmission side, and the encoded signal is input to replica generation means 16. Thereby, since a replica signal is generated using a signal with few errors after error correction, it is possible to prevent deterioration of replica signal generation accuracy due to a determination error, and it is possible to separate and extract signals with high accuracy. .

<Fourth Embodiment>
FIG. 23 is a block diagram showing a configuration example of a signal separation device according to the fourth exemplary embodiment of the present invention. The passband variable bandpass filter 11 (11 ₁ , 11 ₂ , 11 ₃ ,..., 11 _k ), Stage 18 (18) comprising equalization determination means 15 (15 ₁ , 15 ₂ , 15 ₃ ,..., 15 _k ) and replica generation means 16 (16 ₁ , 16 ₂ , 16 ₃ ,..., 16 _k ). ₁ , 18 ₂ ,..., 18 _N ). In this figure as well, the passband variable bandpass filter 11 and the equalization determination means 15 are operated by the signal parameter detection means 12, the extraction order determination means 13, and the parameter control means 14, as in the configuration of FIG. Be controlled.

In the first stage 18 ₁ , the signal band-limited by the passband variable bandpass filter 11 is equalized according to the extraction order determined by the extraction order determination means 13 in the same manner as the signal separation device of FIG. (Primary judgment result) is obtained. Replica generation means 16, and a channel estimation value and the primary judgment result, extraction rank included in the received signal A generates a replica of the 2-position following each signal input to the second stage 18 _2. In the second stage 18 ₂ , a signal obtained by subtracting the replica of the signal of the second or lower extraction order generated in the first stage 18 ₁ from the received signal A is a passband variable bandpass filter # corresponding to the signal of the first extraction order # Input to 1b. The passband variable bandpass filter # 1b limits the band of the input signal, inputs the bandlimited signal to the equalization determination means # 1b, and the equalization determination means # 1b determines whether the input signal is equalized. The determination result (secondary determination result) and the transmission path estimation value are input to the replica generation means # 1b. At this time, the signal input to the passband variable bandpass filter # 1a includes an interference signal in the received signal, whereas the signal input to the passband variable bandpass filter # 1b since that is the minus the replica signal generated by the stage 18 _1, the signal effect of the interference is suppressed. For this reason, the influence of the interference signal in the equalization determination means 15 is suppressed, and a more accurate transmission path estimation value can be obtained as compared with the first stage. Subsequently, replica generation means # 1b generates a replica of the signal ranked first in the extraction order from the input secondary determination result and transmission path estimation value.

  The passband variable bandpass filter # 2b includes, from the received signal A, a signal replica that is generated in the first stage and having the third highest extraction order, and a replica of the signal that is first in the extraction order generated by the replica generation means # 1b. The remaining signal obtained by subtracting is input. Similarly, the passband variable bandpass filter #nb corresponding to the nth extraction order signal has a replica of the first and second extraction order signals generated in the first stage and the second stage. The remaining signal obtained by subtracting the replica of the signal having the extraction order n-1 or higher from the received signal A is input. Those input signals are subjected to band limitation and equalization determination, and the replica generation means 16 generates a replica signal from the secondary determination result in the equalization determination means 15 and the transmission path estimation value.

  In this way, in the q-th stage, the transmission path estimation value is made highly accurate using the replica signal generated in the q-1 stage, and the determination result is made more accurate. When the number of stages is N, the determination result in the equalization determination means 15 at the Nth stage is output as the final determination result.

  By adopting the configuration as described above, it is possible to suppress errors in transmission path estimation values and determination errors due to the influence of interference signals in the configuration as shown in FIG. 3, and it is possible to separate signals with high accuracy. It becomes.

24 and 25 are diagrams illustrating an example of a signal parameter detection method. 24 and 25, a common table is held for transmission / reception of information on modulation schemes, signal bandwidths, center frequencies, and the like that may be used in the transceiver. The transmitting side selects a number corresponding to the signal parameter to be used from the table, generates a data series, and transmits the data series prior to communication. For example, when transmitting a signal with a signal bandwidth of BW _C and a center frequency of _fcB in QPSK, `` No. '' `` 2 '' `` 3 '' `` 2 '' is data-sequenced and modulated prior to communication To send. On the receiving side, as shown in FIG. 25, a common table is used to generate and modulate a sequence in the same manner for all combinations of parameters that may be used, and the correlation detector 121 is used. Perform correlation detection with. The parameter specifying unit 122 determines that a signal parameter such as a modulation scheme, a signal bandwidth, and a center frequency corresponding to the sequence with the highest correlation detection result is used, and outputs the signal parameter B. In this way, it is not necessary to send signal parameters using a unique control channel, so that it is possible to effectively use frequency resources.

<Fifth Embodiment>
Next, FIG. 26 is a block diagram showing a configuration example of a wireless receiver having a wireless transmitter and a multi-user detector according to the fifth embodiment of the present invention.

  In FIG. 26, a transmitter 5-1 (5-1a, 5-1b, 5-1c) includes a modulator 5-11 (5-11a, 5-11b, 5-11c) and a band limiting filter 5-12. (5-12a, 5-12b, 5-12c), transmitter low-pass filter 5-13 (5-13a, 5-13b, 5-13c), baseband-RF converter 5-14 (5-14a 5-14b, 5-14c), antenna 5-15 (5-15a, 5-15b, 5-15c), and encoding unit 5-16 (5-16a, 5-16b) . The encoding unit 5-16 is omitted when error correction is not performed.

  Receiver 5-2 includes RF-baseband converter 5-20 (5-20a, 5-20b), reception-side low-pass filter 5-21 (5-21a, 5-21b), multi-user detector 5 -22, a high-power amplifier 5-26 (5-26a, 5-26b), and an antenna 5-25 (5-25a, 5-25b). FIG. 26 shows a case where the number of reception antennas is two.

  Transmitter 5-1 inputs transmission data 5-10 (5-10a, 5-10b, 5-10c) or data error-corrected and encoded by encoder 5-16 to modulator 5-11. The modulator 5-11 modulates the input data and maps it to a point on the signal space. The band limiting filter 5-12 shapes the waveform of the signal modulated by the modulator 5-11. The baseband-RF conversion unit 5-14 converts the band-limited baseband signal into an RF band signal by amplification or frequency conversion. The transmission-side low pass filter 5-13 suppresses the high frequency component of the signal after frequency conversion. The signal whose high frequency component is suppressed by the transmission-side low pass filter 5-13 is radiated by the transmission antenna 5-15.

  The signal transmitted from the transmission antenna 5-15 is received by the reception antenna 5-25 of the receiver 5-2 via the propagation path 5-3 (5-3a, 5-3b, 5-3c). The received signal is amplified by the high-power amplifier 5-26, and then the noise outside the reception signal band is suppressed by the reception-side low-pass filter 5-21, and the baseband is obtained by the RF-baseband conversion unit 5-20. Converted to a signal. The baseband signal is input to the multi-user detector 5-22. The multi-user detector 5-22 refers to the signal information 5-24 regarding the signal included in the received signal, and determines the received data determination result 5-23 (5-23a, 5-23b, 5-23c from the baseband signal. ) Is output.

  FIG. 27 shows a configuration example of the multi-user detector 5-22. In FIG. 27, the multi-user detector 5-22 includes a band limiting filter 220 (220a, 220b, 220c), a transmission path calculation unit 221 (221a, 221b, 221c), and an MMSE filter 222 (222a, 222b, 222c). And a soft input / output decoder 223 (223a, 223b, 223c), a replica generator 224 (224a, 224b), and a subtractor 225 (225a, 225b).

  First, in the multi-user detector 5-22, the band limitation is performed by the band limiting filter 220a of the signal whose extraction order is the highest in the input signal r (hereinafter, the signal whose extraction order is the kth is referred to as the kth extraction target signal). Then, the band-limited signal is input to the MMSE filter 222a. In the transmission path calculation unit 221a, the reception filter information of the first extraction target signal from the band limiting filter 220a, the symbol rate information of each user's signal included in the reception signal, timing information, and the propagation path 5-3 information Based on the transmission side filter information, ISI of each user's signal included in the input signal r from the transmission side band limiting filter 5-12 to the first extraction target signal band limiting filter 220a on the receiving side. The transmission line state is calculated considering the state of

Here, if the low-pass filters 5-13 and 5-21 in transmission / reception operate ideally and there is no signal distortion, the input signal r is b _k , the modulation signal vector of the k-th extraction signal, and the transmission filter matrix _Is G _{Tx, k} , the state matrix of propagation path 5-3 is H _{p, k} , the noise vector is n, and the total number of signals to be extracted is K,

と表現される。なお、τ_kは各信号の到来タイミングである。このとき、入力信号rは、

It is expressed. Note that τ _k is the arrival timing of each signal. At this time, the input signal r is

により表現される。このとき、D₁+1は第一の抽出対象信号のサンプル点数であり、ベクトルないしは行列の右上に示す「*」、「H」は、それぞれ複素共役、複素共役転置を表す。また、r(m)は時刻mT_S1における受信信号であり、T_Skは第kの抽出対象信号のサンプルの時間間隔である。ここで、送信される変調信号のシンボル数をM_k個とすると、b_kは、

It is expressed by At this time, D ₁ +1 is the number of sample points of the first extraction target signal, and “*” and “H” shown at the upper right of the vector or matrix represent complex conjugate and complex conjugate transpose, respectively. R (m) is a received signal at time mT _S1 , and T _Sk is a time interval of samples of the k-th extraction target signal. Here, if the number of symbols of the modulated signal to be transmitted is M _k , b _k is

と表現される。b_k(m)は、第kの抽出対象信号のm＋1番目の変調信号である。

It is expressed. b _k (m) is the m + 1 th modulated signal of the k th extraction target signal.

The transmission filter matrix G _{Tx, k} is

となる。このとき、g_k(t)は第kの抽出対象信号の送信における帯域制限フィルタ5-12の時間応答関数であり、第kの抽出対象信号の通過帯域幅により決定される。また、T_kは、第kの抽出対象信号のシンボル時間であり、シンボルレートは1/T_kで与えられる。

It becomes. At this time, g _k (t) is a time response function of the band limiting filter 5-12 in transmission of the k th extraction target signal, and is determined by the pass bandwidth of the k th extraction target signal. T _k is the symbol time of the k-th extraction target signal, and the symbol rate is given by 1 / T _k .

The propagation path state matrix H _{p, k} is

と表現される。このとき、h_k(p,q)は、受信信号r(p)において受信される、第q遅延波（遅延時間：qT_S1）の振幅及び位相回転量を表現する複素数である。

It is expressed. At this time, h _k (p, q) is a complex number representing the amplitude and phase rotation amount of the q-th delayed wave (delay time: qT _S1 ) received in the received signal r (p).

At this time, the signal after passing through the band limiting filter 220a on the receiving side is a matrix G _{Rx, 1} representing the band limiting filter 220a,

を用いて、

Using,

となる。このとき、第一の抽出対象信号の到来タイミングに合わせて受信信号をサンプリング、つまり、時刻mT_S1+τ₁で受信信号をサンプリングすると、第二から第Kまでの受信信号の到来タイミングは、相対的に時間τ₁だけずれる。すなわち、受信フィルタ220a通過後の信号は、

It becomes. At this time, when the received signal is sampled in accordance with the arrival timing of the first extraction target signal, that is, when the received signal is sampled at time mT _S1 + τ ₁ , the arrival timings of the second to Kth received signals are relatively Thus, the time τ _{1 is} shifted. That is, the signal after passing through the reception filter 220a is

となる。

It becomes.

  At this time, the transmission path calculation unit 221a, based on (Equation 20), the transmission path matrix of the k-th extraction target signal,

として計算する。同様に、第mの抽出対象信号の処理ブロックにおける伝送路計算部221は、第kの抽出対象信号の伝送路行列を、

Calculate as Similarly, the transmission path calculation unit 221 in the processing block of the m-th extraction target signal, the transmission path matrix of the k-th extraction target signal,

として計算する。

Calculate as

  FIG. 28 shows a configuration example of a block diagram of the transmission path calculation unit in the processing of the m-th extraction target signal.

  In the following, for the sake of simplicity, the transmission path matrix in the processing of the m-th extraction target signal of the k-th extraction target signal,

とする。

And

  As a result, it is possible to easily calculate the transmission path state in consideration of ISI caused by different filter passbands that were not considered in the method of Non-Patent Document 2, and based on the method of Non-Patent Document 3, fractions can be obtained. Compared with the case where the interval-type coefficient variable filter is used, it is possible to suppress an increase in the amount of calculation and deterioration in transmission path estimation accuracy.

  Based on the transmission path matrix calculated as described above, the MMSE filter 222a calculates the filter coefficient w (u) for the u-th symbol of the first extraction target signal by the following equation.

ここで、e_uは、行列の第u行の成分のみを抽出するベクトルであり、σ²は雑音の平均電力、また、I₁はM₁×M₁の単位行列である。また、Λ_kは、第kの抽出対象信号の、実際に送信された信号空間上のシンボル系列b_kと、復調後に生成されるシンボル系列レプリカ

Here, e _u is a vector that extracts only the u-th row component of the matrix, σ ² is the average power of noise, and I ₁ is a unit matrix of M ₁ × M ₁ . Λ _k is a symbol sequence b _k on the actually transmitted signal space of the k-th extraction target signal and a symbol sequence replica generated after demodulation

との差分の共分散行列であり、

And the difference covariance matrix

となる。なお、この共分散行列は、シンボル系列レプリカが全く生成されていない場合、つまり入力信号から第kの抽出対象信号のレプリカ信号を減算していない状況では単位行列、逆に、高精度にレプリカが生成されており、高精度にレプリカ減算ができている状況では零行列に近づく。ここでは、第一の抽出対象信号の処理に際しては、どの信号のレプリカの減算も行っていないので、全てのkに対してΛ_kは単位行列となる。

It becomes. This covariance matrix is a unit matrix when no symbol sequence replica is generated, that is, when the replica signal of the k-th extraction target signal is not subtracted from the input signal. It is generated and approaches the zero matrix in a situation where replica subtraction can be performed with high accuracy. Here, since the subtraction of any signal replica is not performed in the processing of the first extraction target signal, Λ _k is a unit matrix for all k.

Using the filter coefficient w ₁ (u) thus obtained, the received signal is equalized as follows.

この等化後の信号は、軟入出力復号器223aに入力される。軟入出力復号器223aは、入力された等化後の第一の抽出対象信号について、送信側において符号化されている場合は符号化を考慮して、受信データの判定及び送信シンボルに対する尤度を計算する。ここで、変調方式がBPSKである場合、尤度の比の対数値である対数尤度比λ₁(u)は、以下のように記述される。

The equalized signal is input to the soft input / output decoder 223a. The soft input / output decoder 223a determines the received data and the likelihood for the transmission symbol in consideration of encoding when the input first signal to be extracted after equalization is encoded on the transmission side. Calculate Here, when the modulation scheme is BPSK, the log likelihood ratio λ ₁ (u), which is a logarithmic value of the likelihood ratio, is described as follows.

続いて、レプリカ生成器224において、軟入出力復号器223で求めた尤度を用いてシンボル系列のレプリカを生成する。シンボル系列のレプリカを、

Subsequently, the replica generator 224 generates a symbol sequence replica using the likelihood obtained by the soft input / output decoder 223. A replica of the symbol series

とすると、u番目のシンボルのレプリカは、

Then the replica of the uth symbol is

によって計算できる。このシンボル系列レプリカは、次以降に抽出対象となる信号の処理部におけるMMSEフィルタに入力される。また、第一の抽出対象信号の受信信号のレプリカを、送信フィルタ及び受信タイミングを考慮して以下の式

Can be calculated by This symbol series replica is input to the MMSE filter in the signal processing unit to be extracted after the next. Further, the received signal replica of the first extraction target signal is expressed by the following equation in consideration of the transmission filter and the reception timing.

により求め、第二の抽出対象信号の帯域制限フィルタの前段に配置されている減算器225へ入力する。

And is input to the subtracter 225 arranged in the preceding stage of the band limiting filter of the second extraction target signal.

  Subsequently, the process proceeds to signal processing of the second extraction target signal.

  In the processing of the second extraction target signal, first, a replica of the first extraction target signal is subtracted from the input signal. And the subtraction result,

を用いて第一の抽出対象信号と同様の処理を行う。同様に、第mの抽出対象信号は、

Is used to perform the same processing as the first extraction target signal. Similarly, the m-th extraction target signal is

を用いて信号処理を行う。

Is used to perform signal processing.

  In addition, in the detection processing of the m-th extraction target signal, the signal is sequentially demodulated, a replica of the m-th extraction target signal is generated from the demodulated signal, and the replica is used due to the influence of the delay wave. The ISI component can also be removed.

In the present embodiment, an example in which the influence of only the band limit filter 5-12 on the transmission side and the band limit filter 220 on the reception side is taken into account has been described. May be generated. In that case, if the matrix representing the impulse response of the transmission-side low-pass filter 5-13 of the k-th extraction target signal is L _{Tx, k} and the matrix representing the impulse response of the reception-side low-pass filter 5-21 is L _{Rx, k} , The transmission path calculation unit 221 in the processing of the m-th extraction target signal, the transmission path matrix of the k-th extraction target signal,

のように計算することにより、ローパスフィルタ5-13、5-21の影響を考慮して多ユーザ検出を行うことができる。

By calculating in this way, multi-user detection can be performed in consideration of the influence of the low-pass filters 5-13 and 5-21.

  In addition, if the size of the matrix is large, the calculation amount of the inverse matrix calculation becomes extremely large. Therefore, ISI symbols that are affected only by power below a predetermined level with respect to symbols to be demodulated are not considered in the transmission path matrix, so that the transmission path matrix can be reduced to reduce the amount of calculation.

  FIG. 29 is a block diagram illustrating a configuration example in the case where the propagation path state is estimated for all extraction target signals simultaneously. In this configuration example, propagation path information

は伝搬路推定部226により推定され、実際の伝搬路情報の代わりに、推定された伝搬路推定値

Is estimated by the propagation path estimation unit 226, and instead of the actual propagation path information, the estimated propagation path estimated value

を用いて図２７と同様の動作を行う。伝搬路推定部226では、トレーニングシンボルやパイロットシンボルなどの参照シンボルに、各信号の受信タイミングを考慮して送信フィルタ行列を乗算してから、 RLS（Recursive Least Square）アルゴリズムや、LMS（Least Mean Square）アルゴリズムを用いて、伝搬路推定を行う。あらかじめ送信フィルタ行列を乗算することで、フィルタによるISIの影響が伝搬路推定に現れないようにする。これにより、伝搬路の状態のみを高精度に推定することが可能となる。

The same operation as in FIG. The propagation path estimation unit 226 multiplies a reference symbol such as a training symbol or pilot symbol by a transmission filter matrix in consideration of the reception timing of each signal, and then performs an RLS (Recursive Least Square) algorithm or an LMS (Least Mean Square). ) Perform propagation path estimation using an algorithm. By multiplying the transmission filter matrix in advance, the influence of ISI by the filter is prevented from appearing in the propagation path estimation. Thereby, it becomes possible to estimate only the state of the propagation path with high accuracy.

  FIG. 30 is a block diagram illustrating a configuration example when the propagation path state is individually estimated for each extraction target signal. In this configuration, the m-th extraction target signal processing unit estimates the propagation path of the m-th extraction target signal after passing through the band limiting filter 220. Similarly to the simultaneous estimation, the propagation path estimation is performed using the RLS algorithm or the LMS algorithm in consideration of ISI due to the influence of the filter on the transmission side.

  FIG. 31 is a block diagram illustrating a configuration example of the transmission path calculation unit in FIG. Since the transmission path calculation unit 221 in the processing of the m-th extraction target signal performs propagation path estimation only up to the m-th extraction target signal, the propagation path estimation value for the extraction target signals after the (m + 1) th extraction signal is 0. calculate.

  FIG. 32 is a block diagram illustrating a configuration example of a receiver including a multi-user detector. In this configuration example, the receiver 5-2 includes a multistage multiuser detector 5-27 in which a plurality of multiuser detectors 5-28 (5-28a, 5-28b, 5-28c) are connected in cascade. In the multi-stage multi-user detector 5-27, the symbol sequence replica generated in the detection process of the multi-user detector 5-28 in the l-th stage

と、レプリカ信号

And the replica signal

をl+1段目の多ユーザ検出器において用い、繰返し信号検出処理を行うことで、多ユーザ検出の精度を向上させる。

Is used in the l + 1 stage multi-user detector, and the repeated signal detection process is performed to improve the multi-user detection accuracy.

  FIG. 33 is a block diagram showing a configuration example of the multi-user detector 5-28 inside the multi-stage multi-user detector 5-27. FIG. 33 shows an example when the number of receiving antennas is two. The first-stage multi-user detector 5-28 subtracts the replica signal generated by the first-first multi-user detector from the input signal r in the first extraction target signal detection process, and performs the subtraction. The resulting signal,

を用いて信号検出処理を行う。第mの抽出対象信号の検出処理では、第m−1以前の抽出対象信号のレプリカは更新されているので、その更新後のレプリカを減算した結果である以下のような信号を用いる。

The signal detection process is performed using. In the detection process of the m-th extraction target signal, since the replica of the extraction target signal before the m−1th is updated, the following signal that is the result of subtracting the updated replica is used.

多段多ユーザ検出器5-27における伝送路計算部の構成例を図３４に示す。第mの抽出対象信号の伝送路計算部221では、第m以前の抽出対象信号の伝搬路推定値が更新されているので、その更新した値を用いて伝送路行列を計算する。これにより、逐次的に伝搬路推定値が更新されると同時に伝送路行列も更新され、高精度な信号の分離が可能となる。

A configuration example of the transmission path calculation unit in the multistage multiuser detector 5-27 is shown in FIG. The m-th extraction target signal transmission path calculation unit 221 updates the propagation path estimation value of the m-th extraction target signal before the m-th extraction target signal, and calculates the transmission path matrix using the updated value. As a result, the propagation path estimation value is updated sequentially, and at the same time, the transmission path matrix is also updated, thereby enabling high-accuracy signal separation.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to the embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

It is a block diagram showing the structure of the conventional replica production type interference canceller. It is a block diagram showing the structure of the sequential multiuser detection method (conventional method) based on a MMSE filter. It is a block diagram showing the example of a structure of the receiver containing the signal separation apparatus concerning the 1st Embodiment of this invention. It is a conceptual diagram of the signal processing process of a signal separation apparatus. It is a block diagram showing the structural example of the receiver containing the signal separation apparatus concerning the 2nd Embodiment of this invention. It is a block diagram showing the structural example of an extraction order | rank determination means. It is a flowchart showing operation | movement of the quality estimation and order determination means of FIG. It is a block diagram showing the other structural example of an extraction order determination means. It is a flowchart showing operation | movement of the quality estimation and order determination means of FIG. It is a block diagram showing the example of a structure of a mutual interference amount estimation means. It is a block diagram showing the other structural example of a mutual interference amount estimation means. It is a block diagram showing the structural example of the electric power calculation means per unit bandwidth. It is a conceptual diagram showing the relationship between the power of each signal and the signal power per unit bandwidth. It is a conceptual diagram showing the relationship between the use bandwidth of a signal, and a superimposition frequency bandwidth. It is a conceptual diagram showing the amount of mutual interference. It is a block diagram showing the other structural example of an extraction order determination means. It is a flowchart showing operation | movement of the quality estimation and order determination means of FIG. It is a block diagram showing the other structural example of an extraction order determination means. It is a flowchart showing operation | movement of the quality estimation and order determination means of FIG. It is a block diagram showing the structural example of a noise estimation means. It is a conceptual diagram showing operation | movement of a noise estimation means. It is a block diagram showing the example of a structure of the receiver containing the signal separation apparatus concerning the 3rd Embodiment of this invention. It is a block diagram showing the example of a structure of the signal separation apparatus concerning the 4th Embodiment of this invention. It is a block diagram showing an example of the parameter information generation method. It is a block diagram showing the example of a structure of a signal parameter detection means. It is a block diagram showing the example of a structure of the radio | wireless receiver which has the radio | wireless transmitter and multi-user detector concerning the 5th Embodiment of this invention. FIG. 27 is a block diagram illustrating a configuration example of a multi-user detector in FIG. 26. It is a block diagram showing the example of a structure of the transmission line calculation part of FIG. It is a block diagram showing the structural example of the multiuser detector in the case of performing propagation path estimation simultaneously with respect to all the signals. It is a block diagram showing the structural example of the multiuser detector in the case of performing propagation path estimation separately with respect to each signal. FIG. 31 is a block diagram illustrating a configuration example of a transmission path calculation unit in FIG. 30. It is a block diagram showing the structural example of the radio | wireless receiver which has a multistage multiuser detector. It is a block diagram showing the structural example of the multiuser detector which comprises a multistage multiuser detector. It is a block diagram showing the example of a structure of the transmission line calculation part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Transmitter 10 Receiver 11 Passband variable bandpass filter 12 Signal parameter detection means 13 Extraction order determination means 14 Parameter control means 15 Equalization determination means 16 Replica generation means 17 Subtractor

Claims (16)

There are a plurality of transmitting-side radio stations and a plurality of receiving-side radio stations having different signal bandwidths and carrier frequencies of transmission signals, and a radio signal is transmitted from the transmitting-side radio station to the receiving-side radio station that is a communication partner. In a wireless communication system that performs communication by transmitting a signal separation device provided in the reception-side wireless station,
A bandpass filter with a variable passband that can limit the band of the received signal and vary the passband;
Signal parameter detecting means for detecting signal parameters of a plurality of signals included in the received signal;
Extraction order determining means for determining the extraction order of received signals from the received signal and the signal parameters extracted by the signal parameter detecting means;
Parameter control means for controlling the passband of the passband variable bandpass filter from the extraction order determined by the extraction order determination means and the signal parameter extracted by the signal parameter detection means;
Equalization determination means for equalizing and determining an output signal from the passband variable bandpass filter;
Replica generation means for generating a replica of the received signal using the determination result in the equalization determination means and the transmission path estimation value estimated in the equalization processing;
Comprising
Using the difference in signal parameters of the plurality of signals included in the received signal, the plurality of signals are sequentially separated from the received signal by the passband variable bandpass filter and equalization determining means according to the extraction order. A signal separation device characterized by being taken out. The signal separation device according to claim 1,
The extraction order determining means includes
A mutual interference amount estimating means for estimating a mutual interference amount when a plurality of signals included in the received signal interfere with each other from the received signal and the signal parameter;
Quality estimation and rank determination means for determining a rank for separating and extracting a signal included in the reception signal from the reception signal using the estimated mutual interference amount estimated by the mutual interference amount estimation means;
Comprising
The quality estimation and rank determining means sets a reference quality when determining a signal of a predetermined extraction rank as an estimated mutual interference amount with other signals due to a signal whose extraction rank is earlier than the predetermined extraction rank. A signal separation device characterized in that the order is calculated and determined as follows. The signal separation device according to claim 2,
The mutual interference amount estimating means includes:
Signal power estimating means for estimating received power of a plurality of signals included in the received signal;
The power per unit bandwidth of each of the plurality of signals included in the reception signal from the signal parameter and the power estimation value of each of the plurality of signals included in the reception signal estimated by the signal power estimation means. Power calculating means per unit bandwidth for calculating
From the signal parameters, signal superimposition state estimation means for estimating a frequency bandwidth in which a plurality of signals included in the received signal are superimposed on each other and interfere with each other, and
The signal power calculation value per unit bandwidth of each of a plurality of signals included in the reception signal, calculated by the power calculation unit per unit bandwidth, and the reception signal estimated by the signal superposition state estimation unit An interference power calculation means for calculating an estimated mutual interference amount from a superimposed frequency bandwidth of a plurality of signals included therein;
A signal separation device comprising: The signal separation device according to claim 3,
The mutual interference amount estimating means includes:
Using the received signal and the signal parameter, comprising a transmission path estimation means for estimating a transmission path estimation value which is a state of a transmission path with a time spread of a plurality of signals included in the received signal,
The signal power estimation means includes
A signal separation apparatus, wherein power is estimated using a transmission path estimation value for a main wave of each signal estimated by the transmission path estimation means. The signal separation device according to claim 3,
The signal power estimation means includes
A signal separation apparatus, wherein the power of each signal is estimated by performing correlation detection using a known symbol sequence corresponding to each of a plurality of signals included in the received signal. The signal separation device according to claim 3,
The power calculation means per unit bandwidth is:
A signal per unit bandwidth of each signal is obtained by averaging a value obtained by estimating the signal power of each signal for a predetermined time by the signal power estimation unit with the signal bandwidth included in the signal parameter of each signal. A signal separation device for calculating power. The signal separation device according to claim 3,
The signal superposition state estimation means includes
From the center frequency information and the signal bandwidth information included in the signal parameter, the upper and lower limits of the frequency band used for each signal are calculated, and the upper and lower limits of the calculated frequency band are included in the received signal. A signal separation device characterized in that the superposed frequency bandwidth between each signal is calculated by comparing between all signals. The signal separation device according to claim 3,
The interference power calculation means is
By multiplying the signal power per unit bandwidth of each signal obtained by the power calculation means per unit bandwidth by the superimposed frequency bandwidth between the signals obtained by the signal superposition state estimation means, the received signal A signal separation device that calculates interference power between a plurality of signals contained therein. The signal separation device according to claim 1, wherein
The extraction order determining means includes
A mutual interference amount estimating means for estimating a mutual interference amount when a plurality of signals included in the received signal overlap on the frequency axis and interfere with each other from the received signal and the signal parameter;
Noise estimation means for estimating noise power received by a plurality of signals included in the received signal from the received signal and the signal parameter;
Using the estimated mutual interference amount estimated by the mutual interference amount estimation unit and the estimated noise power estimated by the noise estimation unit, the order of separating and extracting the signal included in the received signal from the received signal is determined. A quality estimation and rank determination means to determine;
Comprising
The quality estimation and rank determining means sets a reference quality when determining a signal of a predetermined extraction rank as an estimated mutual interference amount with other signals due to a signal whose extraction rank is earlier than the predetermined extraction rank. A signal separation device characterized in that the order is calculated and determined as follows. The signal separation device according to claim 9, wherein
The noise estimation means includes
Replica signal generating means for generating a replica of the received signal from the received signal and the signal parameter;
A subtractor that subtracts the replica signal generated by the replica signal generation means from the received signal and outputs a residual signal;
A band-pass filter that limits the residual signal with a signal bandwidth of each of a plurality of signals included in the received signal;
Noise power estimation means for calculating power of noise band-limited by the band-pass filter;
Comprising
By estimating the noise signal waveform included in the received signal and limiting the band, the power of the noise affected by the plurality of signals included in the received signal is obtained and output for each signal. Signal separation device. The signal separation device according to claim 1, wherein
The signal separation apparatus according to claim 1, wherein the extraction order determining means sets the extraction order higher as the communication quality is higher. The signal separation device according to claim 1,
Using the passband variable bandpass filter, the equalization determination means, and the replica generation means, and having a plurality of stages for outputting replica signals of each signal included in the received signal,
A signal separation apparatus characterized in that, in a predetermined stage, a replica signal generated in a previous stage is subtracted from a received signal, and band limitation and equalization determination are performed using the result. The signal separation device according to claim 1,
The signal parameter detecting means estimates and detects a signal parameter of each signal included in the received signal from the received signal. The signal separation device according to claim 1,
The signal parameter detecting means is notified in advance of signal parameters of each signal from a transmitting radio station. There are a plurality of wireless transmitters having different signal bandwidths of transmission signals and one wireless receiver having a multi-user detector, and the wireless transmitter transmits wireless signals to the wireless receiver for communication. A signal separation device provided in the wireless receiver in a wireless communication system to perform,
The multi-user detector is
Band limiting filters corresponding to transmission signals from the plurality of wireless transmitters, each having a different pass band;
A transmission line that uses the signal information to calculate a state of a transmission line that is used in the plurality of wireless transmitters and has different passbands for each user, and that takes into account intersymbol interference caused by the filter in the wireless receiver A calculation unit;
A filter coefficient is calculated using the transmission path state calculated in the transmission path calculation unit and the signal information, and band limitation is performed using a replica of the symbol sequence mapped on the signal space estimated in the replica generator. An MMSE filter that equalizes the band-limited signal in the filter;
Soft I / O decoding that uses the signal equalized by the MMSE filter to determine the received data of each user in consideration of the signal information and calculates the likelihood of symbols mapped in the signal space And
A replica of the symbol sequence of the signal mapped on the signal space is generated from the likelihood of the symbol calculated by the soft input / output decoder, and is input to the MMSE filter. Using the generated symbol sequence replica and the signal information A replica generator for generating a received signal replica in consideration of the influence of the transmission path;
A signal separator comprising: a subtracter that subtracts a received signal replica generated by the replica generator from a signal input to a multi-user detector. The signal separation device according to claim 15,
The wireless receiver includes a multistage multiuser detection unit obtained by cascading a plurality of the multiuser detection units,
In the multi-stage multi-user detection unit, the multi-user detection unit performs signal detection and replica generation by using a replica signal generated in a multi-user detection unit at the preceding stage of cascade connection.

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