WIRELESS COMMUNICATION SYSTEM, WIRELESS COMMUNICATION APPARATUS AND WIRELESS COMMUNICATION METHOD, ENCODING APPARATUS AND ENCODING METHOD, AND COMPUTER PROGRAM

• US 20100020891A1
• Filed: 07/15/2009
• Published: 01/28/2010
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: TAKANO, Hiroaki
• Granted Patent: US 8,831,118 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

A wireless communication apparatus includes: plural antennas; a channel matrix acquiring unit acquiring a channel matrix for each sub-carrier; a channel matrix encoding unit encoding the acquired channel matrix of each sub-carrier, by decomposition from signals in fixed-point representation into data and amplitude parts with a predetermined bit width; and a channel matrix information delivery unit delivering the encoded channel matrix information to a communication party. The encoding unit retrieves a first maximum value as the maximum of channel matrix elements in all sub-carriers, in plural levels, and determines an amplitude part and a normalization coefficient for normalizing channel matrix elements to a data part having the predetermined bit width, based on a ratio between a second maximum value as the maximum of channel matrix elements with respect to each sub-carrier and the first maximum value, and multiples channel matrix elements by the normalization coefficient to obtain a data part.

Claims

1. A wireless communication system in which a transmitter and a receiver each having a plurality of antennas form a pair, and the transmitter performs beamforming at each transmit antenna to transmit a multicarrier signal, comprising:

a channel matrix acquiring unit that acquires at the receiver a forward channel matrix from the transmitter to the receiver for each sub-carrier;

a channel matrix encoding unit that encodes the forward channel matrix of each sub-carrier acquired by the channel matrix acquiring unit, by decomposition from signals represented in fixed-point form into a data part and an amplitude part each having a predetermined bit width, at the receiver;

a channel matrix information delivery unit that delivers the encoded channel matrix information from the receiver to the transmitter;

a transmit antenna weight acquiring unit that acquires a weight coefficient of each transmit antenna, by decoding the channel matrix information delivered from the receiver and further analyzing the decoded channel matrix information, at the transmitter; and

a transmit beamforming unit that performs beamforming by digitally weighting each transmit antenna on the basis of the acquired weight coefficient and changing a directivity of the antennas to perform data transmission from the transmitter,

wherein the channel matrix encoding unit

retrieves a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels, and

determines an amplitude part and a normalization coefficient for normalizing each channel matrix element to a data part having the predetermined bit width, with respect to each sub-carrier on the basis of a ratio between a second maximum value as a maximum value of channel matrix elements in each sub-carrier and the first maximum value, and multiples each channel matrix element by the determined normalization coefficient to obtain a data part.

2. The wireless communication system according to claim 1, wherein

the channel matrix encoding unit

includes a normalization coefficient table that describes correspondence between a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers, a range of a second maximum value as a maximum value of channel matrix elements in one sub-carrier, and an amplitude part and a normalization coefficient for normalizing matrix elements in the one sub-carrier, and

receives an input of a first maximum value as a maximum value of channel matrix elements in all sub-carriers and a second maximum value as a maximum value of channel matrix elements in a sub-carrier to be processed, acquires an amplitude part and a normalization coefficient from the normalization coefficient table, and multiples each channel matrix element in the sub-carrier to be processed by the normalization coefficient to obtain a data part.

3. A wireless communication apparatus comprising:

a plurality of antennas;

a channel matrix acquiring unit that acquires a channel matrix for each sub-carrier, by receiving a multicarrier signal containing a known training series transmitted from a communication party including a plurality of antennas;

a channel matrix encoding unit that encodes the channel matrix of each sub-carrier acquired by the channel matrix acquiring unit, by decomposition from signals represented in fixed-point form into a data part and an amplitude part each having a predetermined bit width; and

a channel matrix information delivery unit that delivers the encoded channel matrix information to the communication party,

wherein the channel matrix encoding unit

retrieves a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels, and

determines an amplitude part and a normalization coefficient for normalizing each channel matrix element to a data part having the predetermined bit width, with respect to each sub-carrier on the basis of a ratio between a second maximum value as a maximum value of channel matrix elements in each sub-carrier and the first maximum value, and multiples each channel matrix element by the determined normalization coefficient to obtain a data part.

4. The wireless communication apparatus according to claim 3, wherein

the channel matrix encoding unit

includes a normalization coefficient table that describes correspondence between a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers, a range of a second maximum value as a maximum value of channel matrix elements in one sub-carrier, and an amplitude part and a normalization coefficient for normalizing matrix elements in the one sub-carrier, and

receives an input of a first maximum value as a maximum value of channel matrix elements in all sub-carriers and a second maximum value as a maximum value of channel matrix elements in a sub-carrier to be processed, acquires an amplitude part and a normalization coefficient from the normalization coefficient table, and multiples each channel matrix element in the sub-carrier to be processed by the normalization coefficient to obtain a data part.

5. A wireless communication method for a wireless communication apparatus including a plurality of antennas, comprising the steps of:

acquiring a channel matrix for each sub-carrier, by receiving a multicarrier signal containing a known training series transmitted from a communication party including a plurality of antennas;

encoding the acquired channel matrix of each sub-carrier, by decomposition from signals represented in fixed-point form into a data part and an amplitude part each having a predetermined bit width; and

delivering the encoded channel matrix information to the communication party,

wherein the step of encoding includes

retrieving a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels, and

determining an amplitude part and a normalization coefficient for normalizing each channel matrix element to a data part having the predetermined bit width, with respect to each sub-carrier on the basis of a ratio between a second maximum value as a maximum value of channel matrix elements in each sub-carrier and the first maximum value, and multiplying each channel matrix element by the determined normalization coefficient to obtain a data part.

6. An encoding apparatus that encodes a channel matrix of each sub-carrier represented in fixed-point form in a multicarrier transmission system, comprising:

a quantization unit that retrieves and quantizes a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels;

a normalization coefficient table that describes correspondence between a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers, a range of a second maximum value as a maximum value of channel matrix elements in one sub-carrier, and an amplitude part and a normalization coefficient for normalizing matrix elements in the one sub-carrier;

a first-maximum-value acquiring unit that acquires a first maximum value as a maximum value of channel matrix elements in all sub-carriers;

a coefficient acquiring unit that receives an input of a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers and a second maximum value as a maximum value of channel matrix elements in a sub-carrier to be processed, and acquires an amplitude part and a normalization coefficient from the normalization coefficient table; and

a multiplier that multiples each channel matrix element in the sub-carrier to be processed by a normalization coefficient to obtain a data part,

wherein encoded information of a channel matrix including the amplitude part acquired by the coefficient acquiring unit and the data part obtained by the multiplier is outputted.

7. An encoding method for encoding a channel matrix of each sub-carrier represented in fixed-point form in a multicarrier transmission system, comprising the steps of:

retrieving and quantizing a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels;

acquiring a first maximum value as a maximum value of channel matrix elements in all sub-carriers;

inputting a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers and a second maximum value as a maximum value of channel matrix elements in a sub-carrier to be processed, and by using a normalization coefficient table, acquiring an amplitude part and a normalization coefficient from the normalization coefficient table, the normalization coefficient table describing correspondence between a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers, a range of a second maximum value as a maximum value of channel matrix elements in one sub-carrier, and an amplitude part and a normalization coefficient for normalizing matrix elements in the one sub-carrier; and

multiplying each channel matrix element in the sub-carrier to be processed by a normalization coefficient to obtain a data part,

wherein encoded information of a channel matrix including the acquired amplitude part and the obtained data part is outputted.

8. A computer program which is described in a computer-readable format so that processing on a wireless communication apparatus including a plurality of antennas is executed on a computer, the computer program causing the computer to function as:

channel matrix acquiring means for acquiring a channel matrix for each sub-carrier, by receiving a multicarrier signal containing a known training series transmitted from a communication party including a plurality of antennas;

channel matrix encoding means for encoding the channel matrix of each sub-carrier acquired by the channel matrix acquiring means, by decomposition from signals represented in fixed-point form into a data part and an amplitude part each having a predetermined bit width; and

channel matrix information delivery means for delivering the encoded channel matrix information to a communication party,

wherein the channel matrix encoding means

retrieves a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels, and

determines an amplitude part and a normalization coefficient for normalizing each channel matrix element to a data part having the predetermined bit width, with respect to each sub-carrier on the basis of a ratio between a second maximum value as a maximum value of channel matrix elements in each sub-carrier and the first maximum value, and multiples each channel matrix element by the determined normalization coefficient to obtain a data part.

9. A computer program which is described in a computer-readable format so that a process for encoding a channel matrix of each sub-carrier represented in fixed-point form in a multicarrier transmission system is executed on a computer, the computer program causing the computer to function as:

quantization means for retrieving and quantizing a first maximum value, which is a maximum value of channel matrix elements in all sub-carriers, in a plurality of levels;

a normalization coefficient table that describes correspondence between a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers, a range of a second maximum value as a maximum value of channel matrix elements in one sub-carrier, and an amplitude part and a normalization coefficient for normalizing matrix elements in the one sub-carrier;

first-maximum-value acquiring means for acquiring a first maximum value as a maximum value of channel matrix elements in all sub-carriers;

coefficient acquiring means for receiving an input of a quantized value of a first maximum value as a maximum value of channel matrix elements in all sub-carriers and a second maximum value as a maximum value of channel matrix elements in a sub-carrier to be processed, and acquiring an amplitude part and a normalization coefficient from the normalization coefficient table; and

multiplying means for multiplying each channel matrix element in the sub-carrier to be processed by a normalization coefficient to obtain a data part,

wherein encoded information of a channel matrix including the amplitude part acquired by the coefficient acquiring means and the data part obtained by the multiplying means is outputted.