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

• US 9,369,914 B1
• Filed: 03/24/2014
• Issued: 06/14/2016
• Est. Priority Date: 03/11/2004
• 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
• Application Number:
  US14/223,838
• Time in Patent Office: 813 Days
• Field of Search: 370/203, 370/208, 370/252, 370/328, 370/335, 370/338, 370/465
• US Class Current: 1/1
• 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 wireless signal processing. A described technique includes receiving a signal, having subcarriers, over a wireless channel formed by a number-of-receive-antennas and a number-of-transmit-antennas; determining a signal quality measure of a received signal having subcarriers, the signal quality measure being based on channel gain matrices corresponding respectively to the subcarriers of the received signal, the channel gain matrices having dimensions of the number-of-receive-antennas by the number-of-transmit-antennas; determining a channel quality measure of the received signal that measures a frequency selectivity of the wireless channel; determining a data rate of information transmission over the wireless channel based on the signal quality measure and the channel quality measure, the signal quality measure serving as a primary determinant of the data rate and the channel quality measure serves as a secondary determinant of the data rate; and transmitting information over the wireless channel in accordance with the data rate.

Claims

1. An apparatus comprising:

circuitry configured to derive two or more measures from a received signal having subcarriers, the two or more measures comprising a first measure that is based on channel gain values that are determined respectively for the subcarriers and a second measure that is based on an indication of frequency selectivity in a wireless channel across the subcarriers;

a rate controller configured to determine a data rate of information transmission over the wireless channel based on the two or more measures, 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

circuitry configured to cause a transmission of information over the wireless channel in accordance with the data rate,

wherein the rate controller is configured to determine a first data rate based on the first measure, and determine a second data rate based on the first data rate and the second measure, wherein the transmission of information is in accordance with the second data rate,

wherein the first data rate is determined based on the first measure and one or more signal quality thresholds, and wherein the second data rate is determined based on an adjustment of the first data rate if the first measure falls within a tolerance range of a signal quality threshold of the one or more signal quality thresholds and if the second measure indicates an adjustment is needed.

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

3. The apparatus of claim 2, comprising:

circuitry configured to estimate channel response characteristics of the frequency tones, wherein the second measure is based on the estimated channel response characteristics of the frequency tones.

4. The apparatus of claim 3, wherein the second measure is based on a frequency selectivity measure for single-in-single-out (SISO) based OFDM wireless communications.

5. The apparatus of claim 3, wherein the second measure is based on a geometric mean of reciprocal noise enhancement factors across the frequency tones.

6. An apparatus, comprising:

a channel estimator configured to produce a signal quality measure of a received signal having subcarriers, the signal quality measure being based on channel gain matrices corresponding respectively to the subcarriers of the received signal, the channel gain matrices having dimensions number-of-receive-antennas by number-of-transmit-antennas;

a channel state indicator configured to produce a channel quality measure of the received signal that measures a frequency selectivity of a wireless channel formed by the number-of-receive-antennas and the number-of-transmit-antennas;

a rate controller configured to determine a data rate of information transmission over the wireless channel based on the signal quality measure and the channel quality measure, wherein the signal quality measure serves as a primary determinant of the data rate and the channel quality measure serves as a secondary determinant of the data rate; and

circuitry configured to cause a transmission of information over the wireless channel in accordance with the data rate,

wherein the rate controller is configured to determine a first data rate based on the signal quality measure, and determine a second data rate based on the first data rate and the channel quality measure, wherein the transmission of information is in accordance with the second data rate,

wherein the first data rate is determined based on the signal quality measure and one or more signal quality thresholds, and wherein the second data rate is determined based on an adjustment of the first data rate if the signal quality measure falls within a tolerance range of a signal quality threshold of the one or more signal quality thresholds and if the channel quality measure indicates an adjustment is needed.

7. The apparatus of claim 6, wherein the signal quality measure comprises a received signal strength indication, the rate controller is configured to choose a first rate from a lookup table if the signal quality measure exceeds the signal quality threshold of the one or more signal quality thresholds plus the tolerance range, and the rate controller is configured to choose a second rate from the lookup table if the signal quality measure falls within the tolerance range of the signal quality threshold of the one or more signal quality thresholds and if the channel quality measure fails to exceed a channel quality threshold, the second rate being lower than the first rate.

8. The apparatus of claim 6, wherein the wireless channel comprises a radio frequency channel, and wherein the received signal comprises an orthogonal frequency division multiplexed (OFDM) signal corresponding to multiple frequency tones that make up the radio frequency channel.

9. The apparatus of claim 8, comprising:

circuitry configured to estimate channel response characteristics of the frequency tones, wherein the channel quality measure is based on the estimated channel response characteristics of the frequency tones.

10. The apparatus of claim 9, wherein the channel quality measure is based on a geometric mean of reciprocal noise enhancement factors across the frequency tones.

11. A method comprising:

receiving a signal, having subcarriers, over a wireless channel formed by a number-of-receive-antennas and a number-of-transmit-antennas;

determining a signal quality measure of a received signal having subcarriers, the signal quality measure being based on channel gain matrices corresponding respectively to the subcarriers of the received signal, the channel gain matrices having dimensions of the number-of-receive-antennas by the number-of-transmit-antennas;

determining a channel quality measure of the received signal that measures a frequency selectivity of the wireless channel;

determining a data rate of information transmission over the wireless channel based on the signal quality measure and the channel quality measure, wherein the signal quality measure serves as a primary determinant of the data rate and the channel quality measure serves as a secondary determinant of the data rate, wherein determining the data rate comprises determining a first data rate based on the signal quality measure and determining a second data rate based on the first data rate and the channel quality measure, wherein determining the first data rate comprises selecting the first data rate based on the signal quality measure and one or more signal quality thresholds, wherein determining the second data rate comprises adjusting the first data rate if the signal quality measure falls within a tolerance range of a signal quality threshold of the one or more signal quality thresholds and if the channel quality measure indicates an adjustment is needed; and

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

12. The method of claim 11, wherein the wireless channel comprises a radio frequency channel, and wherein the received signal comprises an orthogonal frequency division multiplexed (OFDM) signal corresponding to multiple frequency tones that make up the radio frequency channel.

13. The method of claim 12, comprising:

estimating channel response characteristics of the frequency tones, wherein determining the channel quality measure comprises deriving the channel quality measure from the estimated channel response characteristics of the frequency tones.

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