JP4912220B2 - Receiving machine - Google Patents

Description

  The present invention relates to a receiver in a communication system employing a MIMO (Multiple Input Multiple Output) spatial multiplexing transmission system.

  In the MIMO spatial multiplexing transmission system, the transmitting side transmits different information from N transmission antennas, and the receiving side includes M receiving antennas to separate and extract N signals. As a conventional receiver of a communication system adopting the MIMO spatial multiplexing transmission system, for example, as described in the following non-patent document, MIMO spatial filtering is performed on a signal obtained by performing DFT processing on M received signal sequences. A receiver that separates N-system transmission signals by performing inverse DFT on the signal has been proposed.

In the spatial filtering technique, for example, when transmission signals are variables x and y, reception signals are A and B, and a, b, c, and d are constants, a simple simultaneous equation such as the following equation (1) is used. And variables x and y are derived.
ax + by = A
cx + dy = B (1)

This method is easy to calculate, but has a problem that the amount of deterioration from the ideal characteristic is large. On the other hand, as another method for separating N transmission signals, there is a method of preparing all the possible candidates for variables x and y called maximum likelihood determination and selecting an optimal set. This method can achieve performance close to ideal characteristics, but the amount of computation increases in proportion to the number of possible candidates. For example, assuming that 16-value modulation, signal block length is 100 symbols, and the number of transmitting antennas is 4, ⁴⁰⁰ astronomical numbers.

M. Morelli, L. Sanguinetti and U. Mengali, “Channel Estimation for Adaptive Frequency-Domain Equalization” IEEE Trans. Wireless Communications Vol.4, No.5, pp.2508-2518, Sept. 2005.

  However, according to the above conventional technique, it is difficult to achieve high signal separation accuracy when spatial filtering is used for transmission signal separation processing, and high signal separation accuracy is realized when maximum likelihood determination is adopted. However, there was a problem that the amount of calculation was large.

  The present invention has been made in view of the above, and an object thereof is to obtain a receiver that realizes high signal separation accuracy with a small amount of calculation.

  In order to solve the above-described problems and achieve the object, the present invention is a receiver that employs a MIMO spatial multiplexing transmission system, and is a frequency domain received signal obtained by frequency conversion of a received signal and a frequency domain value of a transmission path characteristic. And a frequency domain converting means for calculating a processing order of the transmission signal sequence based on a reliability index for each transmission signal sequence, and corresponding to the transmission signal sequence of the frequency domain value of the transmission path characteristic in the processing order Reordering means for rearranging the components to be transmitted, and by repeating the transmission signal sequence estimation process one or more times based on the frequency domain values of the rearranged transmission path characteristics and the frequency domain received signal, MIMO repetitive space separation means for calculating a decision value; and based on the processing order, the decision values of the transmission signal sequence are in the reverse order of the rearrangement by the order rearrangement means. Characterized in that it comprises arrangement and order Gyakunamikawa means changing, to.

  According to the present invention, after the transmission path characteristic values are rearranged in the descending order of the reliability of the transmission signal sequence, the determination process is performed in the rearranged order, and the determination process is repeated to determine the transmission signal sequence. Since the value is obtained, it is possible to obtain a receiver that realizes high signal separation accuracy with a small amount of calculation.

  Embodiments of a receiver according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a functional configuration example of a first embodiment of a receiver according to the present invention. As shown in FIG. 1, the receiver according to the present embodiment includes M (M is the number of receiving antennas) systems of received signal sequence input terminals 1-1 to 1-M and N (N is the number of transmitting antennas) systems. Transmission signal determination value output terminals 2-1 to 2-N, reception signal / transmission path characteristic frequency domain conversion circuit 3, order rearrangement circuit 4, MIMO repetitive space separation circuit 5, and order reverse rearrangement circuit 6 It is equipped with.

  Next, the operation of the present embodiment will be described. First, the received signal / transmission path characteristic frequency domain conversion circuit 3 receives M systems based on time domain received signal sequences received by a receiving antenna (not shown) and input from received signal sequence input terminals 1-1 to 1-M. The frequency domain value of the received signal sequence, the frequency domain value of the transmission path characteristics of the S (S = N × M) system, and the processing order of the N transmission signal sequences are calculated. Then, the reception signal / transmission path characteristic frequency domain conversion circuit 3 sends the frequency domain values of the M system reception signal series to the MIMO repetition space separation circuit 5 and the frequency domain values of the S system transmission path characteristics and the N system transmission signals. The sequence processing order is output to the order rearrangement circuit 4 and the order reverse rearrangement circuit 6. The processing order of the transmission signal sequence is, for example, the order of known reliability.

  Next, the order rearrangement circuit 4 rearranges the N-related components of the N × M transmission path characteristics according to the processing order of the input transmission signal sequence according to the order of the transmission signal sequence (as an N × M matrix). If considered, the order of each row is rearranged in the order of the transmission signal series). Then, the MIMO repetition space separation circuit 5 includes the frequency domain values of the M reception signal sequences output from the reception signal / transmission path characteristic frequency domain conversion circuit 3 and the output S system output from the order rearrangement circuit 4. Based on the frequency domain value of the transmission path characteristics, the same processing as the spatial filtering is repeated (the number of repetitions is 1 or more), and the determination values of N transmission sequences are output to the order reverse rearrangement circuit 6. Based on the processing order of the transmission signal sequence output from the received signal / transmission path characteristic frequency domain conversion circuit 3, the order reverse rearrangement circuit 6 converts the determination values of the N transmission signal sequences in the reverse order (order rearrangement circuit). The order is rearranged to the order in which the order rearranged in step 4 is restored.

  As described above, in the present embodiment, after the order rearrangement circuit 4 performs rearrangement in the order of high reliability, the MIMO repetition space separation circuit 5 repeats the same processing as the spatial filtering, whereby N transmission systems are transmitted. The judgment value of was to be obtained. For this reason, signal separation accuracy can be improved compared to the case of performing spatial filtering without repetition, and by performing rearrangement, signal determination can be performed from a highly reliable transmission signal sequence, and further, Separation accuracy can be increased. Further, in the present embodiment, unlike the maximum likelihood determination, there is no huge amount of calculation that increases exponentially, and an operation that increases less in proportion to the number of repetitions compared to the time of spatial filtering. MIMO spatial separation can be achieved in quantity.

Embodiment 2. FIG.
FIG. 2 is a diagram illustrating a functional configuration example of the MIMO repetition space separation circuit according to the second embodiment of the receiver according to the present invention. The configuration of the receiver of this embodiment is the same as that of Embodiment 1 except that the MIMO repetition space separation circuit 5 of FIG. 1 is replaced with the MIMO repetition space separation circuit shown in FIG.

  As shown in FIG. 2, the MIMO repetition demultiplexing circuit of this embodiment is composed of N × several number of soft decision signal demultiplexing circuits 10-1 to 10-2N, and inputs M frequency domain received signals. A frequency domain reception signal input terminal 7 for input, a frequency domain transmission line characteristic input terminal 8 for inputting the frequency domain transmission line characteristic value of the S system after the rearrangement, and a soft decision value for N system. Are connected to the soft decision value output terminals 9-1 to 9-N. In FIG. 2, the number of repetitions is 2, soft decision signal separation circuits 10-1 to 10-N perform the first iteration, and soft decision signal separation circuits 10- (N + 1) to 10-2N perform the second iteration. Although an example in the case of performing the repetition process is shown, the number of repetitions is not limited to two, and may be any number of times as long as it is one or more.

  Next, the operation of the MIMO repetitive space separation circuit of the present embodiment will be described. The soft decision signal separation circuit 10-1 includes M frequency domain reception signals input from the frequency domain reception signal input terminal 7 and S frequency domain transmission path characteristics input from the frequency domain transmission path characteristic input terminal 8. The reliability information corresponding to the first transmission signal sequence in the processing order is calculated based on the value and output to the soft decision signal separation circuits 10-2 to 10-N, 10- (N + 1). The soft decision signal separation circuit 10-2 includes M frequency domain received signals input from the frequency domain received signal input terminal 7 and S frequency domain transmission path characteristics input from the frequency domain transmission path characteristic input terminal 8. Based on the value and the reliability information of the first transmission signal sequence, the reliability information of the transmission signal sequence corresponding to the second in the processing order is calculated, and the soft decision signal separation circuits 10-3 to 10-N, Output to 10− (N + 1) and 10− (N + 2).

  As described above, the soft decision signal separation circuit 10-i (i = 1 to N) that performs the first iterative process includes the M frequency domain reception signals input from the frequency domain reception signal input terminal 7 and the frequency domain. Based on the S-system frequency domain transmission line characteristic value input from the transmission line characteristic input terminal 8 and the reliability of the transmission signal sequence of the 1st to (i-1) th processing order calculated in advance. The reliability of the transmission signal sequence corresponding to the i-th processing order is calculated. Then, the calculated reliability is output to the soft decision signal separation circuits 10- (i + 1) to 10-N, 10- (N + 1) to 10- (N + i). Note that, when there is no reliability information calculated in advance, as in the processing of the soft decision signal separation circuit 10-1, no reliability information is present (reliability information “0”) and no information is held. Process as follows.

  The soft decision signal separation circuit 10- (N + i) that performs the second iterative process is input from the frequency domain reception signal input terminal 7 and the frequency domain reception signal input terminal 7 and the frequency domain transmission line characteristic input terminal 8. I-th processing based on the frequency domain transmission line characteristic value of the S system and the reliability of the transmission signal sequence in the 1st to (i-1) th processing order of the first iteration calculated in advance. The reliability of the transmission signal sequence corresponding to the order is calculated. Then, the calculated reliability is output to the soft decision signal separation circuits 10- (N + i + 1) to 10-2N. Further, the soft decision signal separation circuit 10- (N + i) outputs the decision value to the order reverse rearrangement circuit 6 via the soft decision value output terminal 9-i. Operations other than the operation of the MIMO repetitive space separation circuit in the present embodiment are the same as those in the first embodiment.

  In the present embodiment, the case where the number of repetitions is two has been described. However, in the case where three or more repetitions are performed, the processing order equal to or lower than the current processing order i calculated in the previous repetition processing is performed. Similarly, based on the reliability corresponding to the transmission signal sequence and the reliability of the transmission signal sequence processed in advance in the current iterative process (processing order is i-1 or less), the transmission signal sequence Calculate reliability. Then, the soft decision signal separation circuit corresponding to the last iterative process may output the decision value to the order reverse rearrangement circuit 6.

  As described above, in the present embodiment, soft decision signal separation circuits 10-1 to 10-2N are used as MIMO repetition space separation circuits, and soft decision signal separation circuits 10-1 to 10-2N are frequency domain received signals. , The frequency domain transmission line characteristic value, the reliability corresponding to the transmission signal sequence in the processing order equal to or lower than the current processing order i calculated in the previous iterative process, and the current iterative process. The reliability of the transmission signal sequence is calculated based on the reliability of the transmission signal sequence (the processing order is i-1 or less). For this reason, as in the first embodiment, the signal separation accuracy can be increased with a small amount of calculation.

Embodiment 3 FIG.
FIG. 3 is a diagram illustrating a functional configuration example of the soft decision signal separation circuit of the MIMO repetition space separation circuit according to the third embodiment of the receiver of the present invention. The configuration of the MIMO repetition spatial circuit of the present embodiment is the same as that of the second embodiment except that the soft decision separation circuit of FIG. 2 is the soft decision signal separation circuit shown in FIG. The configuration other than the MIMO repetition space circuit of the present embodiment is the same as that of the first embodiment.

  As shown in FIG. 3, the soft decision signal separation circuit according to the present embodiment includes a soft decision canceling circuit 24 that generates a signal excluding a signal component to be determined, and a result of spatial filtering of signal components other than the determination target. A residual space filtering circuit 25, an inverse DFT circuit 26 that performs inverse DFT on the output of the residual space filtering circuit 25, a soft decision circuit 27 that calculates a soft decision value based on the inverse DFT result, and a soft decision value (time A DFT circuit 28 that calculates a soft decision value (frequency region) from a region), and a soft decision information processing circuit 29 that calculates reliability information based on the soft decision value (time region) and the soft decision value (frequency region). I have.

  Further, the soft decision signal separation circuit of the present embodiment includes a frequency domain reception signal input terminal 7 for inputting M frequency domains and a frequency domain transmission path for inputting S frequency domain characteristics. A characteristic input terminal 8, a reliability information input terminal 21 for inputting reliability information, a reliability information output terminal 22 for outputting reliability information, and a soft decision value output for outputting a soft decision value And the terminal 23.

  Next, the operation of the soft decision signal separation circuit of this embodiment will be described. First, the soft decision canceling circuit 24 has M frequency domain received signals input from the frequency domain received signal input terminal 7, reliability information input from the reliability information input terminal 21, and frequency domain transmission path characteristics. Based on the frequency domain transmission path characteristics of the S system input from the input terminal 8, M system signals in which signal components other than the signal sequence to be determined are canceled are calculated from the frequency domain received signal and output to the residual spatial filtering circuit 25. To do. Here, the reliability information input from the reliability information input terminal 21 includes the reliability corresponding to the transmission signal sequence in the processing order equal to or lower than the current processing order i calculated in the previous repetition processing, and the current repetition. The reliability of the transmission signal sequence processed in advance of the processing is used. The reliability information that has not been calculated is processed as reliability information “0” so as not to hold the information.

  The residual space filtering circuit 25 is based on the M system signals after the cancellation process, the reliability information, and the frequency domain transmission path characteristics of the S system, except for the transmission sequence signal to be determined that remains after the cancellation process. The result of spatial filtering of the signal component is calculated and output to the inverse DFT circuit 26. The inverse DFT circuit 26 performs inverse DFT on the spatial filtering result output from the residual spatial filtering circuit 25 and outputs the inverse DFT result to the soft decision circuit 27. The soft decision circuit 27 calculates a soft decision value (time domain) based on the inverse DFT result and outputs it to the DFT circuit 28, and at the same time, the final iteration process (when the iteration number is R, the R-th iteration process). If not, it is output to the soft decision information processing circuit 29, and in the case of the final repetitive processing, it is outputted to the soft decision value output terminal.

  The DFT circuit 28 performs DFT on the soft decision value (time domain), calculates the soft decision value (frequency domain), and outputs it to the soft decision information processing circuit 29. The soft decision information processing circuit 29 calculates reliability information based on the soft decision value (time domain) and the soft decision value (frequency domain), and the processing order of the current iterative process via the reliability information output terminal 22. To the reliability information input terminal 21 connected to the soft decision signal separation circuit that performs the subsequent processing, and the soft decision signal separation circuit that performs the processing in the processing order that is equal to or less than the current processing order among the one repetitive processing. Is output.

  The soft decision value output to the soft decision value output terminal 23 in the final repetition process is output to the order reverse rearrangement circuit 6. Operations other than the operation of the soft decision signal separation circuit described above in the present embodiment are the same as those in the first or second embodiment.

  As described above, in this embodiment, the soft decision canceling circuit 24 cancels transmission signal sequences other than the determination target based on the reliability information calculated in advance, thereby improving the MIMO spatial separation accuracy. Can do.

Embodiment 4 FIG.
FIG. 4 is a diagram illustrating a functional configuration example of the MIMO repetitive space separation circuit according to the fourth embodiment of the receiver according to the present invention. The configuration of the receiver of this embodiment is the same as that of Embodiment 1 except that the MIMO repetition space separation circuit 5 of FIG. 1 is replaced with the MIMO repetition space separation circuit shown in FIG.

  As shown in FIG. 4, the MIMO repetition separation circuit of the present embodiment is composed of N × repetition number of hard decision signal separation circuits 12-1 to 12-2N, and inputs M frequency domain reception signals. A frequency domain reception signal input terminal 7 for input, a frequency domain transmission path characteristic input terminal 8 for inputting the frequency domain transmission path characteristic value of the S system after the rearrangement, and a hard decision value for N system. Are connected to the hard decision value output terminals 11-1 to 11-N.

  Next, the operation of the MIMO repetitive space separation circuit of the present embodiment will be described. The hard decision signal separation circuit 12-1 includes M frequency domain received signals input from the frequency domain received signal input terminal 7 and S frequency domain transmission path characteristics input from the frequency domain transmission path characteristic input terminal 8. Based on the value, a hard decision value corresponding to the first transmission signal sequence in the processing order is calculated and output to hard decision signal separation circuits 12-2 to 12-N, 12- (N + 1). The hard decision signal separation circuit 12-2 includes M frequency domain received signals input from the frequency domain received signal input terminal 7 and S frequency domain transmission path characteristics input from the frequency domain transmission path characteristic input terminal 8. A hard decision value corresponding to the second transmission signal sequence in the processing order is calculated based on the value and the hard decision value of the first transmission signal sequence, and hard decision signal separation circuits 12-3 to 12-N, Output to 12- (N + 1), 12- (N + 2).

  In this way, the hard decision signal separation circuit 12-i (i = 1 to N) that performs the first iterative process includes the M frequency domain received signals input from the frequency domain received signal input terminal 7 and the frequency domain. Based on the S-system frequency domain transmission line characteristic value input from the transmission line characteristic input terminal 8 and the hard decision value of the transmission signal sequence of the 1st to (i-1) th processing order calculated in advance. Then, the hard decision value of the transmission signal sequence corresponding to the i-th processing order is calculated. The calculated hard decision values are output to the hard decision signal separation circuits 12- (i + 1) to 12-N and 12- (N + 1) to 12- (N + i). If there is no hard decision value calculated in advance, as in the processing of the hard decision signal separation circuit 12-1, the hard decision value is set to “0” so that no information is held.

  The hard decision signal separation circuit 12- (N + i) that performs the second iterative process is inputted from the frequency domain received signal input terminal 7 and the frequency domain received signal input terminal 7 and the frequency domain transmission line characteristic input terminal 8. Based on the frequency domain transmission line characteristic value of the S system and the hard decision value of the transmission signal sequence of the 1st to (i-1) th processing order of the first iteration calculated in advance. A hard decision value of the transmission signal sequence corresponding to the processing order is calculated. Then, the calculated hard decision value is output to hard decision signal separation circuits 12- (N + i + 1) to 12-2N. Further, the hard decision signal separation circuit 12- (N + i) outputs the hard decision value to the order reverse rearrangement circuit 6 via the hard decision value output terminal 11-i. Operations other than the operation of the MIMO repetitive space separation circuit in the present embodiment are the same as those in the first embodiment.

  In the present embodiment, the case where the number of repetitions is two has been described. However, in the case where three or more repetitions are performed, the processing order equal to or lower than the current processing order i calculated in the previous repetition processing is performed. Similarly, the transmission signal is based on the hard decision value corresponding to the transmission signal sequence and the hard decision value of the transmission signal sequence processed in advance (processing order is i-1 or less) in the current iterative process. A series hard decision value is calculated. Then, the hard decision signal separation circuit corresponding to the last repetitive process may output the hard decision value to the order reverse rearrangement circuit 6.

  Thus, in the present embodiment, hard decision signal separation circuits 12-1 to 12-2N are used as the MIMO repetition space separation circuits, and hard decision signal separation circuits 12-1 to 12-2N are frequency domain received signals. And the frequency domain transmission line characteristic value, the hard decision value corresponding to the transmission signal sequence in the processing order equal to or lower than the current processing order i calculated in the previous repetitive processing, and the current repetitive processing are processed in advance. The hard decision value of the transmission signal sequence is calculated based on the hard decision value of the transmission signal sequence (the processing order is i-1 or less). For this reason, as in the first embodiment, the signal separation accuracy can be increased with a small amount of calculation.

Embodiment 5 FIG.
FIG. 5 is a diagram illustrating a functional configuration example of the hard decision signal separation circuit of the MIMO repetition space separation circuit according to the fifth embodiment of the receiver of the present invention. The configuration of the MIMO repetition spatial circuit of the present embodiment is the same as that of the fourth embodiment, except that the hard decision separation circuit of FIG. 4 is the hard decision signal separation circuit shown in FIG. The configuration other than the MIMO repetition space circuit of the present embodiment is the same as that of the first embodiment.

  As shown in FIG. 5, the hard decision signal separation circuit according to the present embodiment includes a hard decision canceling circuit 31 that generates a signal excluding a signal component to be judged, and a signal generated by the hard decision canceling circuit 31. , A diversity combining circuit 32 that calculates a diversity combined value based on the frequency domain transmission line characteristics of the S system, an inverse DFT circuit 26 that performs inverse DFT on the diversity combined value, and a hard decision value (time domain) based on the inverse DFT result And a DFT circuit 28 for calculating a hard decision value (frequency domain) from the hard decision value (time domain).

  Further, the hard decision signal separation circuit of the present embodiment includes a frequency domain reception signal input terminal 7 for inputting M frequency domains, and a frequency domain transmission path for inputting S system frequency domain characteristics. A characteristic input terminal 8, a hard decision value input terminal 34 for inputting a hard decision value, a first hard decision value output terminal 35 for outputting a hard decision value (time domain), and a hard decision value (frequency) And a second hard decision value output terminal 36 for outputting (region).

  Next, the operation of the hard decision signal separation circuit according to the present embodiment will be described. First, the hard decision canceling circuit 31 includes M frequency domain received signals input from the frequency domain received signal input terminal 7, hard decision values input from the hard decision value input terminal 34, and frequency domain transmission path characteristics. Based on the frequency domain transmission path characteristics of the S system input from the input terminal 8, the M system signals from which signal components other than the signal sequence to be determined are canceled are calculated and output to the diversity combining circuit 32. Here, the hard decision value input from the hard decision value input terminal 34 includes the hard decision value corresponding to the transmission signal sequence of the processing order equal to or lower than the current processing order i calculated in the previous iteration process, and the current decision value. The hard decision value of the transmission signal sequence processed in advance in the iterative process is used. The hard decision value that has not been calculated is processed as "0" so that no information is held.

  The diversity combining circuit 25 calculates a diversity combined value based on the M system signals after the cancellation process and the frequency domain transmission path characteristics of the S system, and outputs them to the inverse DFT circuit 26. The inverse DFT circuit 26 performs inverse DFT on the diversity composite value and outputs the result to the hard decision value circuit 33. The hard decision circuit 33 calculates a hard decision value (time domain) based on the inverse DFT result, and if it is not the final iterative process, it goes to the DFT circuit 28, and if it is the final iterative process, the first hard decision value. Output to the output terminal 35.

  The DFT circuit 28 performs a DFT on the hard decision value (time domain), calculates a hard decision value (frequency domain), and outputs it to the second hard decision value output terminal 36. The hard decision value (frequency domain) output to the second hard decision value output terminal 36 is a hard decision signal separation circuit that performs processing subsequent to the processing order of the current iterative processing, and the one iteration processing ahead. Of these, the processing order is output to the hard decision value input terminal 34 connected to the hard decision signal separation circuit that performs processing below the current processing order.

  The hard decision value output to the first hard decision value output terminal 35 in the final iterative process is output to the order reverse rearrangement circuit 6. Operations other than the operation of the soft decision signal separation circuit described above in the present embodiment are the same as those in the first or fourth embodiment.

  Thus, in the present embodiment, the hard decision canceling circuit 31 cancels transmission signal sequence signals other than the determination target based on the hard decision result of the transmission signal sequence calculated in advance. MIMO space separation accuracy can be increased.

  As described above, the receiver according to the present invention is useful for a communication system employing a MIMO (Multiple Input Multiple Output) spatial multiplexing transmission system, and particularly suitable for a communication system that requires high signal separation accuracy. .

It is a figure which shows the function structural example of Embodiment 1 of the receiver concerning this invention. 6 is a diagram illustrating a functional configuration example of a MIMO repetitive space separation circuit according to a second embodiment. FIG. FIG. 10 is a diagram illustrating a functional configuration example of a soft decision signal separation circuit of a MIMO repetition space separation circuit according to a third embodiment. FIG. 10 is a diagram illustrating a functional configuration example of a MIMO repetition space separation circuit according to a fourth embodiment. FIG. 10 is a diagram illustrating a functional configuration example of a hard decision signal separation circuit of a MIMO repetition space separation circuit according to a fifth embodiment.

Explanation of symbols

1-1 to 1-M received signal series input terminals 2-1 to 2-N transmitted signal determination value output terminals 3 received signal / transmission path characteristic frequency domain conversion circuit 4 order rearrangement circuit 5 MIMO repetition space separation circuit 6 order reverse Rearrangement circuit 7 Frequency domain received signal input terminal 8 Frequency domain transmission line characteristic input terminal 9-1 to 9-N Soft decision value output terminal 10-1 to 10-N Soft decision signal separation circuit 11-1 to 11-N Hard Decision value output terminals 12-1 to 12-N Hard decision signal separation circuit 21 Reliability information input terminal 22 Reliability information output terminal 23 Soft decision value output terminal 24 Soft decision canceling circuit 25 Residual space filtering circuit 26 Inverse DFT circuit 27 Soft decision circuit 28 DFT circuit 29 Soft decision information processing circuit 31 Hard decision canceling circuit 32 Diversity synthesis circuit 33 Hard decision circuit 34 Hard decision value input terminal Child 35 First hard decision value output terminal 36 Second hard decision value output terminal

Claims (2)

A receiver employing a MIMO spatial multiplexing transmission system,
A frequency domain conversion means for calculating a frequency domain received signal obtained by frequency conversion of a received signal and a frequency domain value of transmission path characteristics, and calculating a processing order of transmission signal sequences based on a reliability index for each transmission signal sequence;
Order reordering means for rearranging components corresponding to transmission signal sequences of the frequency domain values of the transmission path characteristics in the processing order;
MIMO repetitive space separation means for calculating a determination value of a transmission signal sequence by repeating a transmission signal sequence estimation process one or more times based on the rearranged frequency domain value of the channel characteristics and the frequency domain received signal;
Based on the processing order, order reverse rearrangement means for rearranging the determination value of the transmission signal sequence in an order reverse to the rearrangement by the order rearrangement means;
With
The MIMO repetitive space separation means includes:
Soft decision signal separation means for outputting reliability information representing the probability of the soft decision value is provided with the number of transmission signal sequences per one iteration process,
The soft decision signal separation means includes the frequency domain values of the rearranged transmission path characteristics, the frequency domain received signal, and reliability information already calculated by the soft decision signal separation means that performs the same number of repetitions, and Soft decision canceling means for outputting a canceling signal which is a signal obtained by removing signal components other than the sequence to be judged from the frequency domain received signal based on reliability information calculated by the previous iteration process When,
Calculated by the canceling signal, the frequency domain values of the rearranged transmission line characteristics, the reliability information already calculated by the soft decision signal separation means for performing the same number of repetitions, and the previous repetition process. Based on the reliability information, a residual spatial filtering means for outputting a filtered signal obtained by spatially filtering a signal component other than the transmission signal sequence signal component to be determined;
Inverse DFT means for inverse DFT processing the filtered signal;
Soft decision means for calculating a soft decision value based on the inverse DFT result;
DFT means for DFT processing the soft decision value;
Soft decision information processing means for calculating reliability information based on the DFT result and the soft decision value;
A receiver comprising: A receiver employing a MIMO spatial multiplexing transmission system,
A frequency domain conversion means for calculating a frequency domain received signal obtained by frequency conversion of a received signal and a frequency domain value of transmission path characteristics, and calculating a processing order of transmission signal sequences based on a reliability index for each transmission signal sequence;
Order reordering means for rearranging components corresponding to transmission signal sequences of the frequency domain values of the transmission path characteristics in the processing order;
MIMO repetitive space separation means for calculating a determination value of a transmission signal sequence by repeating a transmission signal sequence estimation process one or more times based on the rearranged frequency domain value of the channel characteristics and the frequency domain received signal;
Based on the processing order, order reverse rearrangement means for rearranging the determination value of the transmission signal sequence in an order reverse to the rearrangement by the order rearrangement means;
With
The MIMO repetition space separation means includes hard decision signal separation means for calculating frequency domain and time domain hard decision values, and the number of transmission signal sequences per one iteration process,
The hard decision signal separating means is
The frequency domain hard decision value already calculated by the hard decision signal separation means that performs the same number of repetitions of the frequency domain value of the rearranged transmission path characteristics, the frequency domain received signal, and the previous iteration Hard decision canceling means for outputting a canceling signal that is a signal obtained by removing signal components other than the sequence to be determined from the frequency domain received signal based on the frequency domain hard decision value calculated by the processing;
Diversity combining means for performing diversity combining based on the canceling signal and the frequency domain value of the rearranged transmission path characteristics;
An inverse DFT means for inverse DFT processing the diversity combining result;
Hard decision means for calculating a hard decision value in the time domain based on the inverse DFT result;
DFT means for calculating a hard decision value in a frequency domain obtained by performing DFT processing on the hard decision value;
Receiver device you comprising: a.

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