# US 2017/0288910 A1 · Wireless communication apparatus and wireless communication method

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- Number: US 2017/0288910 A1
- Document ID: US20170288910A1
- Status: Published application
- Kind: A1
- Application number: 15/512,684
- Filed: 2015-10-01
- Published: 2017-10-05
- Earliest claimed: 2014-10-07
- Assignees: Mitsubishi Electric Corporation
- Applicants: Mitsubishi Electric Corporation
- Inventors: Hiroki IURA
- Web page: https://patentgrep.com/patent/US20170288910A1

## CPC

- H04L 25/022: {of frequency response}
- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B 7/0697: {using spatial multiplexing}
- H04B 7/10: Polarisation diversity; Directional diversity
- H04J 1/02: Details
- H04L 25/0224: {using sounding signals}
- H04L 25/0232: {by interpolation between sounding signals}
- H04L 25/03343: {Arrangements at the transmitter end}
- H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A wireless communication apparatus configured to select an allocation system for transmission symbols on the basis of transmission line situations between the wireless communication apparatus and terminals includes a channel estimator to estimate transmission line coefficients between communication target terminals and sub-arrays, a resource scheduler to generate, on the basis of the transmission line coefficients, mapping information and transmission weight information by spatial multiplexing and frequency multiplexing and select and output the mapping information and the transmission weight information by one of the multiplexing systems, a symbol mapper to map transmission symbols on a frequency axis on the basis of the mapping information from the resource scheduler, and a pre-coder to perform, on the basis of the transmission weight information from the resource scheduler, a weighting operation concerning a signal mapped by the symbol mapper.

## Claims

### Claim at position 1

1: A wireless communication apparatus including a plurality of analog-beam formation circuits including pluralities of antennas, the wireless communication apparatus comprising:
a channel estimator to estimate transmission line coefficients indicating situations of transmission lines, which are channels between communication target terminals and the analog beam formation circuits;
a resource scheduler to generate, on the basis of the transmission line coefficients, mapping information of transmission symbols by spatial multiplexing and transmission weight information used for a weighting operation to a signal after mapping, generate mapping information and transmission weight information by frequency multiplexing, and select and output the mapping information and the transmission weight information by one of the multiplexing systems;
a symbol mapper to map the transmission symbols on a frequency axis on the basis of the mapping information from the resource scheduler; and
a pre-coder to perform, on the basis of the transmission weight information from the resource scheduler, a weighting operation concerning the signal mapped by the symbol mapper.

### Claim at position 2 (depends on 1)

2: The wireless communication apparatus according to claim 1, wherein
the resource scheduler includes:
a spatial-multiplexing evaluator to generate mapping information and transmission weight information by the spatial multiplexing on the basis of the transmission line coefficients and calculate a total band channel capacity by the spatial multiplexing;
a frequency-multiplexing evaluator to generate mapping information and transmission weight information by the frequency multiplexing on the basis of the transmission line coefficients and calculate a total band channel capacity by the frequency multiplexing; and
a processor to compare the total band channel capacity by the spatial multiplexing and the total band channel capacity by the frequency multiplexing and select and output the mapping information and the transmission weight information from the evaluator having a larger total band channel capacity.

### Claim at position 3 (depends on 2)

3: The wireless communication apparatus according to claim 2, wherein the spatial-multiplexing evaluator includes:
an interference-avoidance pre-coder to perform, when there are a plurality of communication target terminals, on the basis of the transmission line coefficients, subcarrier allocation for simultaneously transmitting signals addressed to the plurality of terminals to the plurality of terminals in same time and at a same frequency and generate an equivalent channel matrix after pre-coding using a weight matrix of the pre-coding; and
a spatial-multiplexing-channel-capacity evaluator to calculate a total band channel capacity by the spatial multiplexing using the equivalent channel matrix, set information concerning the subcarrier allocation by the interference-avoidance pre-coder and the weight matrix of the pre-coding as mapping information and transmission weight information by the spatial multiplexing, and output the mapping information and the transmission weight information together with the total band channel capacity by the spatial multiplexing.

### Claim at position 4 (depends on 2)

4: The wireless communication apparatus according to claim 2, wherein the frequency-multiplexing evaluator includes:
a subcarrier allocator to perform, when there are a plurality of communication target terminals, on the basis of the transmission line coefficients, subcarrier allocation for simultaneously transmitting signals addressed to the plurality of terminals to the plurality of terminals in different sub carriers;
a weighting-coefficient selector to select a weighting coefficient from a codebook for each of the subcarriers on the basis of the transmission line coefficients or a weighting-coefficient generator to generate a weighting coefficient on the basis of the transmission line coefficients; and
a frequency-multiplexing-channel-capacity evaluator to calculate a total band channel capacity by the frequency multiplexing from reception power obtained using the weighting coefficient, set information concerning the subcarrier allocation by the subcarrier allocator and the weighting coefficient selected by the weighting-coefficient selector or the weighting coefficient generated by the weighting-coefficient generator, which generates the weighting coefficient on the basis of the transmission line coefficients, as mapping information and transmission weight information by the frequency multiplexing, and output the mapping information and the transmission weight information together with the total band channel capacity by the frequency multiplexing.

### Claim at position 5 (depends on 4)

5: The wireless communication apparatus according to claim 4, wherein the subcarrier allocator allocates the subcarriers to the terminals on the basis of gains indicated by the transmission line coefficients of the terminals.

### Claim at position 6

6: A wireless communication method in a wireless communication apparatus including a plurality of analog-beam formation circuits including pluralities of antennas, the wireless communication method comprising:
a transmission-line-coefficient estimating step of estimating transmission line coefficients indicating situations of transmission lines, which are channels between communication target terminals and the analog beam formation circuits;
a resource schedule step of generating, on the basis of the transmission line coefficients, mapping information of transmission symbols by spatial multiplexing and transmission weight information used for a weighting operation to a signal after mapping, generating mapping information and transmission weight information by frequency multiplexing, and selecting the mapping information and the transmission weight information by one of the multiplexing systems;
a mapping step of mapping the transmission symbols on a frequency axis on the basis of the mapping information selected in the resource schedule step; and
a pre-coder step of performing, on the basis of the transmission weight information selected in the resource schedule step, a weighting operation concerning the signal mapped in the mapping step.

### Claim at position 7 (depends on 6)

7: The wireless communication method according to claim 6, wherein
the resource schedule step includes:
a spatial-multiplexing evaluating step of generating mapping information and transmission weight information by the spatial multiplexing on the basis of the transmission line coefficients and calculating a total band channel capacity by the spatial multiplexing;
a frequency-multiplexing evaluating step of generating mapping information and transmission weight information by the frequency multiplexing on the basis of the transmission line coefficients and calculating a total band channel capacity by the frequency multiplexing; and
a comparing and selecting step of comparing the total band channel capacity by the spatial multiplexing and the total band channel capacity by the frequency multiplexing and selecting the mapping information and the transmission weight information by the evaluating step having a larger total band channel capacity.

### Claim at position 8 (depends on 7)

8: The wireless communication method according to claim 7, wherein the spatial-multiplexing evaluating step includes:
an interference-avoidance pre-coding step of performing, when there are a plurality of communication target terminals, on the basis of the transmission line coefficients, subcarrier allocation for simultaneously transmitting signals addressed to the plurality of terminals to the plurality of terminals in same time and at a same frequency and generating an equivalent channel matrix after pre-coding using a weight matrix of the pre-coding; and
a spatial-multiplexing-channel-capacity evaluating step of calculating a total band channel capacity by the spatial multiplexing using the equivalent channel matrix, setting information concerning the subcarrier allocation in the interference-avoidance pre-coding step and the weight matrix of the pre-coding as mapping information and transmission weight information by the spatial multiplexing, and outputting the mapping information and the transmission weight information together with the total band channel capacity by the spatial multiplexing.

### Claim at position 9 (depends on 7)

9: The wireless communication method according to claim 7, wherein the frequency-multiplexing evaluating step includes:
a subcarrier allocating step of performing, when there are a plurality of communication target terminals, on the basis of the transmission line coefficients, subcarrier allocation for simultaneously transmitting signals addressed to the plurality of terminals to the plurality of terminals in different sub carriers;
a weighting-coefficient selecting step of selecting a weighting coefficient from a codebook for each of the subcarriers on the basis of the transmission line coefficients; and
a frequency-multiplexing-channel-capacity evaluating step of calculating a total band channel capacity by the frequency multiplexing from reception power obtained using the weighting coefficient, setting information concerning the subcarrier allocation in the subcarrier allocating step and the weighting coefficient in the weighting-coefficient selecting step as mapping information and transmission weight information by the frequency multiplexing, and outputting the mapping information and the transmission weight information together with the total band channel capacity by the frequency multiplexing.

### Claim at position 10 (depends on 9)

10: The wireless communication method according to claim 9, wherein, in the subcarrier allocating step, the subcarriers are allocated to the terminals on the basis of gains indicated by the transmission line coefficients of the terminals.