Method and apparatus for automatic data rate control using channel correlation in a wireless communication system

• US 20050136844A1
• Filed: 09/24/2004
• Published: 06/23/2005
• Est. Priority Date: 12/09/2003
• Status: Abandoned Application

• Current Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Schenk, Tim, Giesberts, Pieter-Paul Severin
• Application Number:
  US10/949,444
• Publication Number:
  US 20050136844A1
• Time in Patent Office: Days
• US Class Current: 455/67.130
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy

Abstract

A method and apparatus are provided for automatic data rate control in wireless communication systems, such as wireless LANs. A wireless communication device according to the present invention includes a data rate controller that adapts a transmission rate based on a channel correlation measure. The channel correlation measure may be, for example, eigenvalues or singular values of a channel matrix. The data rate controller may also consider the signal quality, channel delay spread or both in determining a data rate.

Claims

1. A wireless communication device, comprising:

a data rate controller that adapts a transmission rate of transmitted data based on a measure of channel correlation.

2. The wireless communication device of claim 1, wherein said data rate controller further adapts said transmission rate based on current link information.

3. The wireless communication device of claim 2, wherein said current link information includes one or more of a signal to noise ratio, a channel delay spread measure and a balance of missed and received acknowledgement messages.

4. The wireless communication device of claim 1, wherein said transmission rate defines one or more of a number of antennas transmitting independent data streams, a modulation type, a constellation size and a coding rate.

5. The wireless communication device of claim 1, wherein said data rate controller adapts said transmission rate based on an anticipated signal quality for a next frame transmission.

6. The wireless communication device of claim 1, wherein said data rate controller adapts said transmission rate based on data rate advice that decreases a data rate if a current signal quality is below a minimum required signal quality for a given data rate.

7. The wireless communication device of claim 1, wherein said data rate controller adapts said transmission rate based on data rate advice that increases a data rate if a current signal quality is above a minimum required signal quality for a given data rate.

8. The wireless communication device of claim 1, wherein said device is implemented in accordance with the IEEE 802.11 Standard.

9. The wireless communication device of claim 1, wherein said device is implemented in accordance with the HIPERLAN/2 Standard.

10. The wireless communication device of claim 1, further comprising a table that provides data rate advice given one or more of a current signal quality and a correlation value.

11. The wireless communication device of claim 1, wherein said channel correlation is measured using eigenvalues of a channel matrix.

12. The wireless communication device of claim 1, wherein said channel correlation is measured using singular values of a channel matrix.

13. A method, comprising the steps of:

transmitting one or more frames of data; and

adapting a transmission rate of said data based on a measure of channel correlation.

14. The method of claim 13, wherein said adapting step further adapts said transmission rate based on current link information.

15. The method of claim 14, wherein said current link information includes one or more of a signal to noise ratio, a channel delay spread measure and a balance of missed and received acknowledgement messages.

16. The method of claim 13, wherein said transmission rate defines one or more of a number of antennas transmitting independent data streams, a modulation type, a constellation size and a coding rate.

17. The method of claim 13, wherein said adapting step adapts said transmission rate based on an anticipated signal quality for a next frame transmission.

18. The method of claim 13, wherein said adapting step adapts said transmission rate based on data rate advice that decreases a data rate if a current signal quality is below a minimum required signal quality for a given data rate.

19. The method of claim 13, wherein said adapting step adapts said transmission rate based on data rate advice that increases a data rate if a current signal quality is above a minimum required signal quality for a given data rate.

20. The method of claim 13, further comprising the step of accessing a table that provides data rate advice given one or more of a current signal quality and a correlation value.

21. The method of claim 13, wherein said channel correlation is measured using eigenvalues of a channel matrix.

22. The method of claim 13, wherein said channel correlation is measured using singular values of a channel matrix.

23. A transmission method, comprising the steps of:

measuring a signal quality and a channel correlation;

transmitting one or more frames of data; and

adapting a transmission rate of said data based on said measured signal quality and channel correlation.

24. The method of claim 23, wherein said channel correlation is measured using eigenvalues of a channel matrix.

25. The method of claim 23, wherein said channel correlation is measured using singular values of a channel matrix.