Wireless communication system, wireless communication apparatus and wireless communication method, encoding apparatus and encoding method, and computer program

• US 8,831,118 B2
• Filed: 07/15/2009
• Issued: 09/09/2014
• Est. Priority Date: 07/23/2008
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Takano, Hiroaki
• Primary Examiner(s): Nguyen, Leon-Viet
• Assistant Examiner(s): Hassan, Sarah
• Application Number:
  US12/503,245
• Publication Number:
  US 20100020891A1
• Time in Patent Office: 1,882 Days
• Field of Search: 375/260, 375/257, 370/310
• 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, implemented by receiver circuitry, configured to acquire at the receiver a forward channel matrix from the transmitter to the receiver for each sub-carrier;

a channel matrix encoding unit, implemented by the receiver circuitry, configured to encode 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, implemented by the receiver circuitry, configured to deliver the encoded channel matrix information from the receiver to the transmitter;

a transmit antenna weight acquiring unit, implemented by transmitter circuitry, configured to acquire 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, implemented by the transmitter circuitry, configured to perform 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 is configured to

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

determine the amplitude part and a normalization coefficient for normalizing each channel matrix element to the 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 multiply each channel matrix element by the determined normalization coefficient to obtain the data part for each sub-carrier.

2. The wireless communication system according to claim 1, wherein the channel matrix encoding unit, for a sub-carrier to be processed of the sub-carriers,

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

is configured to receive an input of the first maximum value as the maximum value of channel matrix elements in all sub-carriers and the second maximum value as the maximum value of channel matrix elements in the sub-carrier to be processed, acquire the amplitude part and the normalization coefficient from the normalization coefficient table, and multiply each channel matrix element in the sub-carrier to be processed by the normalization coefficient to obtain the data part.

3. A wireless communication apparatus comprising:

a plurality of antennas;

a channel matrix acquiring unit, implemented by circuitry, configured to acquire 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, implemented by the circuitry, configured to encode 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, implemented by the circuitry, configured to deliver the encoded channel matrix information to the communication party,

wherein the channel matrix encoding unit is configured to

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

determine the amplitude part and a normalization coefficient for normalizing each channel matrix element to the 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 multiply each channel matrix element by the determined normalization coefficient to obtain the data part for each sub-carrier.

4. The wireless communication apparatus according to claim 3, wherein the channel matrix encoding unit, for a sub-carrier to be processed of the sub-carriers,

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

is configured to receive an input of the first maximum value as the maximum value of channel matrix elements in all sub-carriers and the second maximum value as the maximum value of channel matrix elements in the sub-carrier to be processed, acquire the amplitude part and the normalization coefficient from the normalization coefficient table, and multiply each channel matrix element in the sub-carrier to be processed by the normalization coefficient to obtain the 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 the amplitude part and a normalization coefficient for normalizing each channel matrix element to the 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 the data part for each sub-carrier.

6. A non-transitory computer readable recording medium having recorded therein a computer executable program that, when executed on a wireless communication apparatus including a plurality of antennas and a computer, causes the computer to perform a method, the method comprising:

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 channel matrix of each sub-carrier acquired by the acquiring, 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 a communication party,

wherein the encoding further 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 the amplitude part and a normalization coefficient for normalizing each channel matrix element to the 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 the data part for each sub-carrier.