Adaptively determining a data rate of packetized information transmission over a wireless channel

• US 8,687,510 B1
• Filed: 03/30/2010
• Issued: 04/01/2014
• Est. Priority Date: 07/20/2004
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Shirali, Kedar, Narasimhan, Ravi, Hsu, Yungping
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): NG, CHRISTINE Y
• Application Number:
  US12/750,531
• Time in Patent Office: 1,463 Days
• Field of Search: 370/203, 370/208, 370/252, 370/328, 370/335, 370/338, 370/465
• US Class Current: 370/252
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/22 Negotiating communication rate

Abstract

Systems and techniques relating to processing a signal received over a wireless channel. A technique includes adaptively determining a data rate of packetized information transmission based on both a signal quality measure of a received signal and a channel quality measure derived from the received signal, the channel quality measure being indicative of frequency selectivity in the wireless channel. An apparatus includes a channel estimator configured to be responsive to a received OFDM signal corresponding to multiple frequency tones of the channel, and configured to evaluate channel response characteristics of the frequency tones; and a channel state indicator configured to generate a channel quality measure usable along with a signal quality measure in adaptively determining a data rate of packetized information transmission, wherein the channel quality measure is generated from the channel response characteristics of the frequency tones and is indicative of frequency selectivity in the wireless channel.

Claims

1. A method comprising:

determining a data rate of information transmission over a wireless channel based on two or more measures derived from a received signal, wherein the two or more measures comprise a first measure that is based on a strength of the received signal and a second measure that is indicative of frequency selectivity in the wireless channel, wherein determining the data rate comprises determining channel gain values respectively for two or more different subcarriers associated with the received signal, and determining the second measure based on a combination of the channel gain values to measure the frequency selectivity in the wireless channel across the two or more different subcarriers associated with the received signal, and wherein the first measure serves as a primary determinant of the data rate and the second measure serves as a secondary determinant of the data rate; and

transmitting information over the wireless channel in accordance with the data rate.

2. The method of claim 1, wherein determining the data rate comprises:

determining a first data rate based on the first measure; and

determining a second data rate based on the first data rate and the second measure,

wherein transmitting the information comprises transmitting the information over the wireless channel in accordance with the second data rate.

3. The method of claim 2, wherein determining the first data rate comprises selecting the first data rate based on the first measure and one or more signal quality thresholds, wherein determining the second data rate comprises adjusting the first data rate if the first measure falls within a tolerance range of a signal quality threshold and if the second measure indicates an adjustment is needed.

4. The method of claim 1, wherein the wireless channel comprises a radio frequency channel, and the received signal comprises an orthogonal frequency division multiplexed (OFDM) signal corresponding to multiple frequency tones that make up the radio frequency channel.

5. The method of claim 4, further comprising:

estimating channel response characteristics of the frequency tones; and

deriving the second measure from the estimated channel response characteristics of the frequency tones.

6. The method of claim 5, wherein deriving the second measure comprises calculating a frequency selectivity measure for single-in-single-out (SISO) based OFDM wireless communications.

7. The method of claim 5, wherein deriving the second measure comprises calculating a geometric mean of reciprocal noise enhancement factors across the frequency tones.

8. A method, comprising:

operating multiple transmit antennas and multiple receive antennas to transmit and receive data over a wireless channel;

determining a data rate of information transmission over the wireless channel based on two or more measures derived from multiple received signals that are received by the multiple receive antennas, respectively, wherein the two or more measures comprise a first measure that is based on a strength of the multiple received signals and a second measure that is indicative of frequency selectivity in the wireless channel, wherein determining the data rate comprises determining channel gain information respectively for two or more different subcarriers associated with the received signal, and determining the second measure based on a combination of the channel gain information to measure the frequency selectivity in the wireless channel across the two or more different subcarriers associated with the received signals, and wherein the first measure serves as a primary determinant of the data rate and the second measure serves as a secondary determinant of the data rate; and

transmitting information over the wireless channel in accordance with the data rate.

9. The method of claim 8, wherein determining the data rate comprises:

determining a first data rate based on the first measure; and

determining a second data rate based on the first data rate and the second measure,

wherein transmitting the information comprises transmitting the information over the wireless channel in accordance with the second data rate.

10. The method of claim 9, wherein determining the first data rate comprises selecting the first data rate based on the first measure and one or more signal quality thresholds, wherein determining the second data rate comprises adjusting the first data rate if the first measure falls within a tolerance range of a signal quality threshold and if the second measure indicates an adjustment is needed.

11. The method of claim 8, wherein the multiple received signals comprise an orthogonal frequency division multiplexed (OFDM) signal corresponding to multiple frequency tones.

12. The method of claim 11, comprising:

estimating channel response characteristics of the frequency tones; and

deriving the second measure from the estimated channel response characteristics of the frequency tones.

13. The method of claim 12, wherein deriving the second measure comprises calculating a geometric mean of reciprocal noise enhancement factors across the frequency tones.

14. The method of claim 12, wherein deriving the second measure comprises calculating a frequency selectivity measure for multiple-in-multiple-out (MIMO) based OFDM wireless communications, wherein the frequency selectivity measure is based on a channel gain matrix having dimensions number-of-receive-antennas by number-of-transmit-antennas.

15. The method of claim 8, wherein determining the channel gain information respectively for the two or more different subcarriers comprises determining channel gain matrices respectively for the two or more different subcarriers, the channel gain matrices each having dimensions number-of-receive-antennas by number-of-transmit-antennas, and wherein the second measure is a frequency selectivity measure that is based on a combination of the channel gain matrices.

16. An apparatus, comprising:

circuitry to receive data via multiple receive antennas and transmit data via multiple transmit antennas over a wireless channel; and

circuitry configured to determine a data rate of information transmission over the wireless channel based on two or more measures derived from multiple received signals that are received by the multiple receive antennas, respectively, to cause transmission of information over the wireless channel in accordance with the data rate, and to determine channel gain information respectively for two or more different subcarriers associated with the received signal,

wherein the two or more measures comprise a first measure that is based on a strength of the multiple received signals and a second measure that is indicative of frequency selectivity in the wireless channel, wherein the second measure is determined based on the channel gain information to measure the frequency selectivity in the wireless channel across the two or more different subcarriers associated with the received signals, and wherein the first measure serves as a primary determinant of the data rate and the second measure serves as a secondary determinant of the data rate.

17. The apparatus of claim 16, wherein the circuitry configured to determine the data rate comprises circuitry to determine a first data rate based on the first measure and to determine a second data rate based on the first data rate and the second measure.

18. The apparatus of claim 17, wherein the circuitry configured to determine the data rate comprises circuitry to select the first data rate based on the first measure and one or more signal quality thresholds and to adjust the first data rate if the first measure falls within a tolerance range of a signal quality threshold and if the second measure indicates an adjustment is needed.

19. The apparatus of claim 16, wherein the multiple received signals comprise an orthogonal frequency division multiplexed (OFDM) signal corresponding to multiple frequency tones, the apparatus comprising:

circuitry to estimate channel response characteristics of the frequency tones; and

circuitry to derive the second measure from the estimated channel response characteristics of the frequency tones.

20. The apparatus of claim 19, wherein the circuitry to derive the second measure is configured to calculate a geometric mean of reciprocal noise enhancement factors across the frequency tones.

21. The apparatus of claim 19, wherein the circuitry to derive the second measure is configured to calculate a frequency selectivity measure for multiple-in-multiple-out (MIMO) based OFDM wireless communications, wherein the frequency selectivity measure is based on a channel gain matrix having dimensions number-of-receive-antennas by number-of-transmit-antennas.

22. The apparatus of claim 16, wherein the channel gain information comprises two or more channel gain matrices respectively associated with the two or more different subcarriers, the channel gain matrices each having dimensions number-of-receive-antennas by number-of-transmit-antennas, and wherein the second measure is a frequency selectivity measure that is based on a combination of the channel gain matrices.