JP7391273B1 - Wireless communication device, control circuit, storage medium and signal processing method - Google Patents

Abstract

A wireless communication device (31) that receives wireless signals transmitted from a base station of a wireless communication system to which one-frequency repetition is applied using a plurality of antennas (40-1, 40-2), each of which is different. A plurality of demodulation units (50, 60) that perform demodulation processing on a wireless signal to generate decoding results and posterior log-likelihood ratio information, and one of the decoding results generated by the plurality of demodulation units. , and a decoding result selection unit (70) that selects and outputs a selection based on posterior log-likelihood ratio information.

Description

The present disclosure relates to a wireless communication device, a control circuit, a storage medium, and a signal processing method used in a wireless communication system.

For efficient frequency use in mobile communication systems, it is desirable that adjacent cells operate on the same radio frequency. Allocating the same radio frequency to adjacent cells is called one frequency repetition, reuse 1, or the like. Single-frequency repetition, in which the same radio frequency is assigned to adjacent cells for operation, can achieve efficient frequency utilization and has been adopted in commercial radio systems and the like. However, when repeating one frequency, inter-cell interference occurs in cell boundary areas, so interference countermeasures are required. Non-Patent Document 1 discloses a technique for separating and detecting a desired signal from a received signal containing interference components by suppressing interference using multiple antennas (array antennas) at a mobile station as a measure against inter-cell interference. .

Shunsuke Uehashi, Hiroshi Nishimoto, Hiroshi Tomitsuka, Hiroyasu Sano, Masaki Hanya, "Co-channel interference suppression method for differential space-time block code transmission applied to multi-station simultaneous transmission system", IEICE Japanese Journal B, Vol.J105-B No.5, pp.446-453, May 2022

Here, the number of antennas in an array antenna is called the array degree of freedom, and in a receiving station using an array antenna, there is a design issue as to whether to use the array degree of freedom for spatial signal separation performance or spatial diversity performance. There is a trade-off relationship between the two, and if the array degree of freedom is used for spatial signal separation performance, an interference suppression effect can be obtained, but the spatial diversity effect is reduced, and stable reception quality cannot be obtained. On the other hand, if the array degrees of freedom are used for spatial diversity performance, the reception quality is stabilized, but the interference suppression effect is reduced, and when the amount of interference is large, the demodulation performance is degraded.

As disclosed in Non-Patent Document 1, by applying directivity control using an array antenna, interference suppression, etc. in demodulation processing, it is possible to spatially separate signals and demodulate the desired signal even when the amount of interference is large. It becomes possible to do so. On the other hand, when the amount of interference is small, there are cases where better demodulation performance is achieved by applying spatial diversity reception using an array antenna.

The quality of the signal detected by demodulation can be determined by, for example, CRC (Cyclic Redundancy Check). On the other hand, real-time voice calls are often the main application in business radio, and in voice codecs, rather than decoding the data series that caused a CRC error and causing data loss (underflow), it is better to If so, better audio quality may be obtained by using it for decoding.

The present disclosure has been made in view of the above, and an object of the present disclosure is to obtain a wireless communication device that can maintain good demodulation performance even when wireless reception conditions change.

In order to solve the above-mentioned problems and achieve the objectives, the present disclosure provides a wireless communication device that uses multiple antennas to receive wireless signals transmitted from a base station of a wireless communication system to which single frequency repetition is applied. There are a plurality of demodulation units each performing different demodulation processing on the wireless signal to generate a decoding result and posterior log-likelihood ratio information, and one of the decoding results generated by the plurality of demodulation units. a decoding result selection unit that selects and outputs a decoding result based on an error detection result and a posteriori log-likelihood ratio information for the decoding result, and the demodulation process executed by the demodulation unit includes an error correction decoding process, and the decoding result selection unit selects and outputs the The result selection unit is characterized in that it selects one decoding result based on posterior log-likelihood ratio information when an error is detected in all the decoding results .

The wireless communication device according to the present disclosure has the advantage of being able to maintain good demodulation performance even when the wireless reception situation changes.

A diagram showing a configuration example of a wireless communication system according to Embodiment 1. Block diagram showing a configuration example of a wireless communication device according to Embodiment 1 Flowchart showing the operation of the wireless communication device according to Embodiment 1 Flowchart showing the operation of the demodulator of the wireless communication device according to Embodiment 1 A diagram illustrating a configuration example of a processing circuit when the processing circuit included in the wireless communication device according to Embodiment 1 is implemented by a processor and memory. A diagram illustrating an example of a processing circuit in a case where the processing circuit included in the wireless communication device according to Embodiment 1 is configured with dedicated hardware. Block diagram showing a configuration example of a wireless communication device according to Embodiment 2 Flowchart showing the operation of the demodulator of the wireless communication device according to Embodiment 2 First diagram for explaining the effects of the second embodiment Second diagram for explaining the effects of the second embodiment Block diagram showing a modification of the wireless communication device according to Embodiment 2

Below, a wireless communication device, a control circuit, a storage medium, and a signal processing method according to embodiments of the present disclosure will be described in detail based on the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration example of a wireless communication system 1 according to the first embodiment. The wireless communication system 1 includes a mobile station (hereinafter referred to as MS (Mobile Station)) 30 and terrestrial base stations (hereinafter referred to as BS (Base Station)) 11 and 21. In the wireless communication system 1 shown in FIG. 1, the BS 11 belongs to the cell 10, and the BS 21 belongs to the cell 20. Further, it is assumed that the wireless communication system 1 uses one frequency repetition. That is, the cell 10 and the cell 20 are operated using the same radio frequency, and the BS 11 and BS 21 are transmitting different signals using the same radio frequency. MS 30 includes a wireless communication device 31 according to this embodiment.

FIG. 1 shows an example where MS 30 is located in a boundary area between cell 10 and cell 20. Here, for convenience of explanation, the desired cell is assumed to be cell 10, and the interfering cell is assumed to be cell 20. The desired cell is the cell to which the BS with which MS 30 communicates belongs. That is, in the example shown in FIG. 1, MS 30 is connected to BS 11 and receives a signal transmitted from BS 11 as a desired signal. In addition, in the following description, when BS11 and BS21 are not distinguished, they may be simply referred to as BS. Further, in FIG. 1, the number of BSs belonging to each cell 10 and cell 20 is one, but this is just an example, and the number of BSs belonging to each cell is not limited to the example of FIG. 1.

Let the number of antennas included in each BS be Ntx, and the number of antennas included in the MS 30 be Nrx. In this embodiment, Ntx=1 will be described as an example. Furthermore, in this embodiment, Nrx is assumed to be 2 or more because the MS 30 performs directivity control, but to simplify the explanation, the case where Nrx=2 will be described as an example. That is, in this embodiment, the array degree of freedom of the MS 30 is two. In FIG. 1, the antenna is provided outside the BS and the MS 30, but it is assumed that the antenna is also included in the BS and the MS 30. The same applies to Embodiment 2 and subsequent embodiments.

In this embodiment, the MS 30 will be specifically explained using downlink communication as an example in which the BS transmits a signal and the MS 30 receives the signal.

In addition to a data signal, a reference signal sequence for estimating channel information is inserted into a radio frame that is a downlink communication signal transmitted from a BS. In the wireless communication system 1, individual reference signal sequences are assigned to each BS. Therefore, the MS 30 can identify the BS and individually estimate channel information using the reference signal sequence. It is also assumed that the MS 30 also knows cell identification information for identifying the cell to which each BS belongs. The cell identification information is, for example, an identifier such as an ID (IDentifier) that can identify a cell. Here, the channel information includes a complex amplitude value of a wireless transmission path, that is, a channel response. In general, channel response varies due to fading caused by radio wave propagation including physical transmission distance, positional relationship, reflection, scattering, etc. between the BS and MS 30. Further, a data signal inserted into a radio frame is generated by adding CRC check data to an information bit sequence and performing error correction encoding. As the error correction code, an error correction code that assumes repeated decoding, such as a turbo code or an LDPC (Low Density Parity Check) code, is used. In iterative decoding, when the validity of the bit sequence increases through the iterative processing, the posterior LLR (soft decision output) tends to converge to a large value.

The wireless communication device 31 that constitutes the MS 30 will be explained. FIG. 2 is a block diagram showing a configuration example of the wireless communication device 31 according to the first embodiment. The wireless communication device 31 receives a wireless frame, which is a signal transmitted from a BS, using a plurality of antennas. In this embodiment, in order to explain a wireless communication device 31 that solves the problem when an MS 30 receives a signal from a BS, FIG. 2 shows components related to reception processing, and components related to transmission processing. is omitted.

As shown in FIG. 2, the wireless communication device 31 includes antennas 40-1 and 40-2, a synchronization section 41, a channel estimation section 42, demodulation sections 50 and 60, and a decoding result selection section 70. . The demodulation section 50 includes a signal processing section 51, a demapping section 52, and an error correction decoding section 53. Similarly, the demodulation section 60 includes a signal processing section 61, a demapping section 62, and an error correction decoding section 63. The same signal is input from the synchronization section 41 to each of the demodulation sections 50 and 60. Note that in this embodiment, for the sake of simplifying the explanation, two different demodulation sections 50 and 60 are provided, but the present invention is not limited to this, and three or more demodulation sections may be provided.

Here, it is assumed that the signal processing section 51 of the demodulation section 50 and the signal processing section 61 of the demodulation section 60 perform different signal processing. Therefore, the demodulating section 50 and the demodulating section 60 output different processing results.

For example, the signal processing unit 51 performs maximum ratio combining processing to realize spatial diversity reception using two antennas, and the signal processing unit 61 performs interference suppression processing based on a zero-forcing standard using two antennas. However, the processing performed by the signal processing section 51 and the signal processing section 61 is not limited to these. In the present embodiment, the explanation will be made assuming that the signal processing section 51 performs maximum ratio combining processing, and the signal processing section 61 performs interference suppression processing based on the Zero-forcing norm.

The demapping unit 52 and the demapping unit 62 may be blocks that perform the same process, or may be blocks that perform different processes. In this embodiment, the description will be given assuming that the demapping unit 52 and the demapping unit 62 are blocks that perform the same processing. Similarly, the error correction decoding section 53 and the error correction decoding section 63 may be blocks that perform the same processing, or may be blocks that perform different processing. In this embodiment, the explanation will be given assuming that error correction decoding section 53 and error correction decoding section 63 are blocks that perform the same processing. FIG. 3 is a flowchart showing the operation of the wireless communication device 31 according to the first embodiment.

Antennas 40-1 and 40-2 receive signals transmitted from the BS (step S11). Antennas 40-1 and 40-2 output received signals to synchronization section 41. In the following description, the antennas 40-1 and 40-2 may be referred to as antennas 40 if they are not distinguished from each other. As described above, the MS 30, ie, the wireless communication device 31, includes Nrx=2 antennas 40.

The synchronization unit 41 performs timing synchronization using the reception signal received by the antenna 40 (step S12), and detects a radio frame from the reception signal. The synchronization unit 41 outputs the detected radio frame to the channel estimation unit 42. Furthermore, the synchronization section 41 outputs the received signal to the demodulation section 50 and the demodulation section 60. Note that the synchronization unit 41 may perform frequency synchronization in addition to timing synchronization.

The channel estimator 42 extracts a reference signal sequence from the radio frame detected by the synchronizer 41 and estimates channel information (step S13). Specifically, the channel estimator 42 uses, as channel information, cell identification information that identifies the cell to which the BS belongs and the antenna 40 of the MS 30 for each BS based on the reference signal sequence of the radio frame included in the received signal. Estimate the channel response for each channel. The channel estimator 42 outputs a channel information estimate value, which is the estimated channel information, to the signal processor 51 of the demodulator 50 and the signal processor 61 of the demodulator 60.

The demodulation units 50 and 60 perform demodulation processing on the received signal input from the synchronization unit 41 using the channel information estimation value input from the channel estimation unit 42 (step S14), and select the processing result as a decoding result. It outputs to section 70.

Demodulation processing by demodulation sections 50 and 60 will be explained. To simplify the explanation, the demodulator 50 will be explained here, but the same applies to the demodulator 60. That is, the description of the signal processing unit 51 is also common to the signal processing unit 61, the description of the demapping unit 52 is also common to the demapping unit 62, and the description of the error correction decoding unit 53 is the same as that of the error correction decoding unit 63. are also common.

FIG. 4 is a flowchart showing the operation of demodulator 50 of wireless communication device 31 according to the first embodiment.

In the demodulation unit 50, the signal processing unit 51 calculates the directivity weights corresponding to the antennas 40-1 and 40-2 from the channel information estimate estimated by the channel estimation unit 42, and calculates the directivity weights corresponding to the antennas 40-1 and 40-2. Signal processing is performed to multiply the signal (step S21). The signal processing unit 51 multiplies the received signal by the directivity weight and outputs the result to the demapping unit 52. The directivity weights here include directivity weights for the directions seen from each of the antennas 40-1 and 40-2, and also include weights for realizing interference suppression. Standards for calculating the directivity weights include, but are not limited to, the above-mentioned maximum ratio combination and Zero-forcing. As described above, in this embodiment, the signal processing section 51 performs maximum ratio combining processing, and the signal processing section 61 performs interference suppression processing based on the Zero-forcing norm.

The demapping unit 52 performs a demapping process to calculate a soft input value, that is, a log-likelihood ratio (LLR) from the received signal after the directivity weight multiplication by the signal processing unit 51 (step S22). . The demapping unit 52 is assumed to perform detection processing and LLR calculation of digital modulation signals such as PSK (Phase Shift Keying) modulation signals and QAM (Quadrature Amplitude Modulation) modulation signals. Here, in order to make it possible to compare the magnitude of the post-LLR handled by the error correction decoding section 53 and the decoding result selection section 70 in the subsequent stage between a plurality of different demodulation sections, the demapping section 52 uses the digital modulation signal to be detected. It also has a scaling function that makes the sizes (also called constellation sizes) uniform on average. There are various methods to implement the scaling function, such as a method of estimating and correcting the magnitude of the digitally modulated signal at the time of detection from the channel estimation value and directivity weight, and a method of estimating and correcting the magnitude of the digitally modulated signal at the time of detection, A method of calculating and correcting the average amplitude value or average power value can be applied.

The error correction decoding unit 53 inputs the LLR calculated by the demapping unit 52 to the error correction decoder and performs error correction decoding (step S23), and outputs the decoding result, which is a bit sequence after error correction, and the a posteriori LLR information. The decoding result is output to the decoding result selection unit 70 (step S24). If interleaving is applied to the error correction encoded bit sequence on the transmitting side, the error correction decoding unit 53 also performs deinterleaving. If a scrambler is applied to the bit sequence on the transmitting side, the error correction decoding unit 53 applies the descrambler to the bit sequence after error correction. The error correction decoder needs to be a decoder capable of soft decision output (output of a posteriori LLR). When the error correction code is a turbo code, error correction is performed using an error correction decoder such as a MAP (Maximum a posteriori Probability) decoder, and when the error correction code is an LDPC code, for example, a decoder based on the Sum-Product algorithm. A decoding unit 53 is realized. The posterior LLR information is information based on the posterior LLR sequence corresponding to the bit sequence after error correction, and various formats are possible. Since the posterior LLR has a positive or negative value, for example, the value of each posterior LLR may be converted into an absolute value, or the value obtained by taking the average within a radio frame, but the value is not limited to these. In the description of this embodiment, the a posteriori LLR information is assumed to be a single value obtained by taking the absolute value of each a posteriori LLR and averaging it within a radio frame.

Returning to the description of the overall operation of the wireless communication device 31, the decoding result selection section 70 selects one of the decoding results input from each of the demodulation sections 50 and 60 (step S15) and outputs it.

The details of the selection process by the decoding result selection unit 70 will be explained. The inputs of the decoding result selection unit 70 are the error-corrected bit sequence and post-LLR information output from the error correction decoding unit 53 of the demodulation unit 50 and the error correction decoding unit 63 of the demodulation unit 60. These are the corrected bit sequence and posterior LLR information. The output of the decoding result selection section 70 is one of the two bit sequences. The decoding result selection section 70 first compares the a posteriori LLR information output from the demodulating section 50 and the a posteriori LLR information output from the demodulating section 60 for each radio frame. The decoding result selection unit 70 then selects the demodulation unit that outputs the a posteriori LLR information with the larger value, and outputs the error-corrected bit sequence output by the selected demodulation unit as the decoding result of the radio frame. .

Next, the hardware configuration of the wireless communication device 31 will be explained. In the wireless communication device 31, the plurality of antennas 40 are realized by array antennas. The synchronization section 41, the channel estimation section 42, the signal processing sections 51 and 61, the demapping sections 52 and 62, the error correction decoding sections 53 and 63, and the decoding result selection section 70 are realized by processing circuits. The processing circuit may be a processor and memory that executes a program stored in memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

FIG. 5 is a diagram illustrating a configuration example of processing circuit 400 in a case where the processing circuit included in wireless communication device 31 according to Embodiment 1 is implemented by processor 401 and memory 402. A processing circuit 400 shown in FIG. 5 is a control circuit and includes a processor 401 and a memory 402. When the processing circuit 400 includes a processor 401 and a memory 402, each function of the processing circuit 400 is realized by software, firmware, or a combination of software and firmware. Software or firmware is written as a program and stored in memory 402. In the processing circuit 400, each function is realized by the processor 401 reading and executing a program stored in the memory 402. That is, the processing circuit 400 includes a memory 402 for storing a program that will result in the processing of the wireless communication device 31 being executed. This program can also be said to be a program for causing the wireless communication device 31 to execute each function realized by the processing circuit 400. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

Here, the processor 401 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). The memory 402 may also be a non-volatile or volatile memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), or EEPROM (registered trademark) (Electrically EPROM). This includes semiconductor memory, magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Discs).

FIG. 6 is a diagram illustrating an example of the processing circuit 403 in the case where the processing circuit included in the wireless communication device 31 according to the first embodiment is configured with dedicated hardware. The processing circuit 403 shown in FIG. 6 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. applicable. Regarding the processing circuit, a part may be realized by dedicated hardware, and a part may be realized by software or firmware. In this way, the processing circuit can implement each of the above-mentioned functions using dedicated hardware, software, firmware, or a combination thereof.

The decoding result selection unit 70 described in this embodiment compares the a posteriori LLR information output from the demodulating unit 50 and the a posteriori LLR information output from the demodulating unit 60 for each radio frame, and selects the one with the larger value. The operation of selecting and outputting the bit sequence output from the demodulator is illustrated. However, the present invention is not limited to this, and the error correction decoding sections 53 and 63 may output the magnitude of the posterior LLR for each bit as posterior LLR information, and the decoding result selection section 70 may compare the magnitude of the posterior LLR for each bit. The decoding result may be selected and output each time.

As described above, according to the present embodiment, the wireless communication device 31 included in the MS 30 constituting the wireless communication system 1 can perform multiple different Appropriate decoding results can be selected each time from among the decoding results depending on the radio reception situation, and good demodulation performance can be maintained.

Embodiment 2.
In the first embodiment, the selection criterion in the decoding result selection section 70 was the size of the a posteriori LLR information calculated in each demodulation section. In the second embodiment, a case will be described in which a CRC result is used in addition to the post-LLR information as a selection criterion in the decoding result selection section 70. The following explanation will focus on the differences from the first embodiment, and the parts that are not described are the same as the first embodiment.

FIG. 7 is a block diagram showing a configuration example of a wireless communication device 31a according to the second embodiment. The differences from the wireless communication device 31 according to Embodiment 1 are demodulation sections 50a and 60a, error correction decoding sections 53a and 63a, and decoding result selection section 70a. The demodulators 50a and 60a differ from the demodulators 50 and 60 of the wireless communication device 31 according to the first embodiment in error correction decoders 53a and 63a.

FIG. 8 is a flowchart showing the operation of demodulators 50a and 60a of wireless communication device 31a according to the second embodiment. In the flowchart shown in FIG. 8, the operations in steps S21 and S22 are similar to the operations in steps S21 and S22 in the flowchart showing the operations of demodulators 50 and 60 according to the first embodiment in FIG.

In demodulation units 50a and 60a, error correction decoding units 53a and 63a perform error correction processing that performs a CRC check on the bit sequence after error correction decoding, in addition to the processing of error correction decoding units 53 and 63 according to the first embodiment. (Step S23a), and outputs the processing result, specifically, the decoding result which is a bit sequence after error correction, the posterior LLR information, and the CRC result to the decoding result selection unit 70a (Step S24a).

The decoding result selection unit 70a compares the CRC results before comparing the post-LLR information, unlike the processing of the decoding result selection unit 70 according to the first embodiment. As described above, if CRC check data is added to the information bit sequence, the quality of the bit sequence can be determined based on the CRC result. Therefore, the decoding result selection unit 70a sets the first selection criterion for the decoding results in each of the demodulation units 50a and 60a to be the quality of the CRC result. If any decoding result is a CRC error, the decoding result selection unit 70a sets the second selection criterion to the size of the post-LLR information, and selects and outputs the decoding result by the demodulation unit with the larger post-LLR information.

Next, the effects of this embodiment will be explained using computer simulation results assuming MS reception in a cell boundary area. The number of receiving antennas was Nrx=2, the modulation method was QPSK (Quadrature Phase Shift Keying), and a turbo code (constraint length 4, coding rate 1/2) was used as an error correction code. Assuming VoIP (Voice over Internet Protocol), the information length is 200 bytes (data 198 bytes, CRC 2 bytes), and the radio frame length is 1600 symbols due to turbo encoding and QPSK modulation. It was assumed that radio propagation was quasi-static Rayleigh fading and that channel estimation using reference signals was performed ideally.

FIG. 9 is a first diagram for explaining the effects of the second embodiment. Specifically, the decoding when the desired-to-interference signal power ratio (DUR) is 10 dB. FIG. 7 is a diagram showing subsequent bit error rate characteristics. FIG. 10 is a second diagram for explaining the effects of the second embodiment, and in detail is a diagram showing the bit error rate characteristics after decoding with respect to DUR when the SNR is 20 dB. Here, "MRC" is the characteristic when the decoding result selection section 70a selects and outputs only the bit sequence output by the demodulation section 50a that performs maximum ratio combining, that is, the decoding result selection section 70a is on the side of the demodulation section 50a. This is the bit error rate characteristic when it is assumed that the bit sequence of is always selected. Similarly, “ZF-IR” is a characteristic when the decoding result selection unit 70a selects and outputs only the bit sequence output by the demodulation unit 60a that performs interference suppression based on the Zero-forcing norm. “LLR-SEL” is a characteristic when this embodiment is applied, that is, a characteristic when the decoding result selection unit 70a performs bit sequence selection based on the CRC and the post-LLR information. “ideal” is a characteristic when the bit sequence output by the demodulator 50a and the bit sequence output by the demodulator 60a are ideally selected. From the characteristics shown in FIGS. 9 and 10, it can be seen that the demodulators 50a and 60a differ in quality depending on the SNR and DUR. On the other hand, when bit sequence selection by the decoding result selection unit 70a of the present embodiment is applied, a demodulation method with fewer errors can be selected for each radio frame, and the result is almost as good as when selecting an ideal bit sequence. It has achieved excellent demodulation performance.

In this embodiment, an example has been described in which a CRC check is performed in the error correction decoding sections 53a and 63a, and the CRC result is output to the decoding result selection section 70a. However, the present invention is not limited to this, and the decoding result selection unit may perform a CRC check on the output bit sequence of each demodulation unit, and select the demodulated bit sequence using the CRC result and post-LLR information. . FIG. 11 is a block diagram showing a modification of the wireless communication device according to the second embodiment, and specifically, the wireless communication device 31b according to the second embodiment when a CRC check is performed in the decoding result selection section. FIG. 2 is a block diagram showing a configuration example. The block diagram is similar to the wireless communication device 31 according to the first embodiment shown in FIG. As described above, the decoding result selection unit 70b performs a CRC check on the output bit sequences of the demodulation units 50 and 60, and selects the bit sequence of the demodulation unit 50 and the bit sequence of the demodulation unit 60 based on the CRC result and the post-LLR information. Select one of the series.

As described above, according to the present embodiment, in the wireless communication system 1, the wireless communication device 31a or 31b included in the MS 30 can perform CRC processing even in an environment where the wireless reception conditions such as the amount of interference and received signal power vary. By comparing the results and the post-LLR information step by step, an appropriate decoding result can be selected each time depending on the radio reception situation, and good demodulation performance can be maintained.

The configurations shown in the embodiments above are merely examples, and can be combined with other known techniques, or can be combined with other embodiments, within the scope of the gist. It is also possible to omit or change part of the configuration.

1 wireless communication system, 10, 20 cell, 11, 21 terrestrial base station, 30 mobile station, 31, 31a, 31b wireless communication device, 40-1, 40-2 antenna, 41 synchronization unit, 42 channel estimation unit, 50, 50a, 60, 60a demodulation section, 51, 61 signal processing section, 52, 62 demapping section, 53, 53a, 63, 63a error correction decoding section, 70, 70a, 70b decoding result selection section.

Claims (5)

A wireless communication device that uses a plurality of antennas to receive wireless signals transmitted from a base station of a wireless communication system to which one frequency repetition is applied,
a plurality of demodulation units each performing different demodulation processing on the wireless signal to generate a decoding result and posterior log-likelihood ratio information;
a decoding result selection unit that selects and outputs one of the decoding results generated by the plurality of demodulation units based on the error detection result for the decoding result and the posterior log-likelihood ratio information ;
Equipped with
The demodulation processing executed by the demodulation unit includes error correction decoding processing,
The decoding result selection unit selects one decoding result based on the posterior log-likelihood ratio information when an error is detected in all the decoding results.
A wireless communication device characterized by: A wireless communication device that uses a plurality of antennas to receive wireless signals transmitted from a base station of a wireless communication system to which one frequency repetition is applied,
a plurality of demodulation units each performing different demodulation processing on the wireless signal to generate a decoding result and posterior log-likelihood ratio information;
a decoding result selection unit that selects and outputs one of the decoding results generated by the plurality of demodulation units based on the posterior log-likelihood ratio information;
Equipped with
Each of the plurality of demodulators includes:
a signal processing unit that performs signal processing for combining or interference suppression on signals received at each antenna;
a demapping unit that performs demapping processing on the received signal after the signal processing has been performed;
an error correction decoding unit that performs error correction decoding processing on the received signal after the demapping processing has been performed;
Equipped with
The demapping unit performs scaling processing to equalize the magnitude of the digital modulation signal to be detected on average among the plurality of demodulation units.
A wireless communication device characterized by: A control circuit that controls a wireless communication device that uses a plurality of antennas to receive wireless signals transmitted from a base station of a wireless communication system to which one-frequency repetition is applied,
a demodulation step of performing a plurality of different demodulation processes on the wireless signal to generate a decoding result and posterior log-likelihood ratio information;
a decoding result selection step of selecting one of the decoding results generated in the demodulation step based on the error detection result for the decoding result and the posterior log-likelihood ratio information ;
causing the wireless communication device to execute
The demodulation processing performed in the demodulation step includes error correction decoding processing,
In the decoding result selection step, if an error is detected in all the decoding results, one decoding result is selected based on the posterior log-likelihood ratio information.
A control circuit characterized by: A storage medium storing a program for controlling a wireless communication device that uses a plurality of antennas to receive wireless signals transmitted from a base station of a wireless communication system to which one-frequency repetition is applied,
The program is
a demodulation step of performing a plurality of different demodulation processes on the wireless signal to generate a decoding result and posterior log-likelihood ratio information;
a decoding result selection step of selecting one of the decoding results generated in the demodulation step based on the error detection result for the decoding result and the posterior log-likelihood ratio information ;
causing the wireless communication device to execute
The demodulation processing performed in the demodulation step includes error correction decoding processing,
In the decoding result selection step, if an error is detected in all the decoding results, one decoding result is selected based on the posterior log-likelihood ratio information.
A storage medium characterized by: A signal processing method executed by a wireless communication device that uses a plurality of antennas to receive a wireless signal transmitted from a base station of a wireless communication system to which one frequency repetition is applied, the method comprising:
a demodulation step of performing a plurality of different demodulation processes on the wireless signal to generate a decoding result and posterior log-likelihood ratio information;
a decoding result selection step of selecting one of the decoding results generated in the demodulation step based on the error detection result for the decoding result and the posterior log-likelihood ratio information ;
including;
The demodulation processing performed in the demodulation step includes error correction decoding processing,
In the decoding result selection step, if an error is detected in all the decoding results, one decoding result is selected based on the posterior log-likelihood ratio information.
A signal processing method characterized by:

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