SYSTEM AND METHOD FOR ADAPTIVE BIT LOADING SOURCE CODING VIA VECTOR QUANTIZATION

• US 20050195905A1
• Filed: 03/08/2005
• Published: 09/08/2005
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kowalski, John M.
• Granted Patent: US 7,408,998 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A communication system includes a data transmitter and a data receiver in which the data transmitter transmits data using a multicarrier modulation, such as an OFDM modulation technique. The data receiver determines a predetermined level of modulation for at least one carrier of the multicarrier modulation corresponding to a received signal-to-noise ratio for the carrier using a vector quantization technique. The predetermined level of modulation for each carrier is based on an index to a codeword in a codebook corresponding to the signal-to-noise ratio for the carrier. The index to the codeword is a nearest neighbor to a vector corresponding to the signal-to-noise ratio for the carrier, and the codeword for each predetermined level of modulation is determined based on an adaptive-bit-loading technique. The data receiver transmits the index to the codeword for each carrier to the data transmitter in order to update the modulation at the data transmitter.

Claims

1. A communication system, comprising,

a data transmitter transmitting data using a multicarrier modulation;

and

a data receiver determining a predetermined level of modulation for at least one carrier of the multicarrier modulation corresponding to a received signal-to-noise ratio for the carrier using a vector quantization technique.

2. The communication system according to claim 1, wherein the data receiver determines the predetermined level of modulation for each carrier further based on an index to a codeword in a codebook corresponding to the signal-to-noise ratio for the carrier.

3. The communication system according to claim 2, wherein the index to the codeword is a nearest neighbor to a vector corresponding to the signal-to-noise ratio for the carrier.

4. The communication system according to claim 3, wherein the codeword for each predetermined level of modulation is determined based on an adaptive-bit-loading technique.

5. The communication system according to claim 1, wherein the data receiver transmits the index to the codeword for each carrier to the data transmitter.

6. The communication system according to claim 1, wherein the multicarrier modulation is based on an Orthogonal Frequency Division Multiplexing (OFDM) modulation technique.

7. A receiver in a multicarrier modulation system, comprising,

an estimater estimating a received signal-to-noise ratio for at least one carrier of the multicarrier modulation system for data received from a data transmitter;

and

a vector quantizer determining a predetermined level of modulation for each carrier of the multicarrier modulation based on the received signal-to-noise ratio for the carrier using a vector quantization technique.

8. The receiver according to claim 7, wherein the predetermined level of modulation for each carrier is based on an index to a codeword in a codebook corresponding to the signal-to-noise ratio for the carrier.

9. The receiver according to claim 8, wherein the index to the codeword is a nearest neighbor to a vector corresponding to the signal-to-noise ratio for the carrier.

10. The receiver according to claim 9, wherein the codeword for each predetermined level of modulation is determined based on an adaptive-bit-loading technique.

11. The receiver according to claim 7, wherein the receiver further comprises a transmitter that transmits the index to the codeword for each carrier to the data transmitter.

12. The receiver according to claim 7, wherein the multicarrier modulation of the multicarrier modulation system is based on an Orthogonal Frequency Division Multiplexing (OFDM) modulation technique.

13. A multicarrier-modulation method, comprising,

estimating a received signal-to-noise ratio for at least one carrier of a multicarrier-modulation signal for data received from a data transmitter;

and

determining a predetermined level of modulation for each carrier of the multicarrier modulation based on the received signal-to-noise ratio for the carrier using a vector quantization technique.

14. The method according to claim 13, further comprising determining an index to a codeword in a codebook based on the received signal-to-noise ratio for each carrier of the multicarrier modulation, the codeword representing the predetermined level of modulation for the carrier.

15. The method according to claim 14, wherein the index to the codeword is a nearest neighbor to a vector corresponding to the signal-to-noise ratio for the carrier.

16. The method according to claim 15, further comprising determining the codeword for each predetermined level of modulation based on an adaptive-bit-loading technique.

17. The method according to claim 15, further comprising transmitting the index to the codeword for each carrier to the data transmitter.

18. The method according to claim 13, wherein the multicarrier modulation is based on an Orthogonal Frequency Division Multiplexing (OFDM) modulation technique.