Techniques for explicit feedback delay measurement

• US 7,720,030 B2
• Filed: 02/28/2006
• Issued: 05/18/2010
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Oren, Kaidar, Assaf, Kasher, Gal, Basson, Jorge, Myszne, Solomon, Trainin B.
• Primary Examiner(s): Bost; Dwayne
• Assistant Examiner(s): Mehra; Inder P
• Application Number:
  US11/364,934
• Publication Number:
  US 20070201566A1
• Time in Patent Office: 1,540 Days
• Field of Search: 370/334, 370/335, 370/342, 370/400, 370/465, 455/25, 455/69, 455/101, 455/557, 455/562.1, 455/575.7, 375/259, 375/267, 375/299, 713/166
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/043 using best eigenmode, e.g. beam forming or beam steering
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0643 Feedback on request
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0222 Estimation of channel variability, e.g. coherence bandwidth, coherence time, fading frequency
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

Techniques for explicit feedback delay measurement are described. An apparatus may comprise a processor to generate a steering matrix for transmit spatial processing over a channel, determine a delay time associated with explicit feedback information for the channel, and determine whether to modify the steering matrix with the explicit feedback information based on the delay time. Other embodiments are described and claimed.

Claims

1. An apparatus, comprising a processor to generate a steering matrix for transmit spatial processing over a channel, determine a delay time associated with explicit feedback information for said channel, estimate a time constant for channel variations of said channel, compare said time constant with said delay time, and modify said steering matrix with said explicit feedback information based on said comparison.

2. The apparatus of claim 1, comprising a transceiver coupled to said processor, said transceiver to send a channel state information feedback request message, and receive a channel state information feedback response message with said explicit feedback information.

3. The apparatus of claim 1, comprising a transceiver coupled to said processor, said transceiver to receive a channel state information feedback response message with said explicit feedback information and a time stamp for when a corresponding channel state information feedback request message was received, said processor to determine said delay time using said time stamp.

4. The apparatus of claim 1, said processor to modify said steering matrix with channel state information from said explicit feedback information.

5. The apparatus of claim 1, said processor to modify said steering matrix by replacing said steering matrix with a different steering matrix from said explicit feedback information.

6. A system, comprising:

an antenna array;

a transceiver coupled to said antenna array, said transceiver to receive explicit feedback information for a channel; and

a processor coupled to said transceiver, said processor to generate a steering matrix for transmit spatial processing over a channel using said antenna array, determine a delay time associated with said explicit feedback information, estimate a time constant for channel variations of said channel, compare said time constant with said delay time, and modify said steering matrix with said explicit feedback information based on said comparison.

7. The system of claim 6, said transceiver to send a channel state information feedback request message, and receive a channel state information feedback response message with said explicit feedback information and a time stamp for when said channel state information feedback request message was received, said processor to determine said delay time using said time stamp.

8. The system of claim 6, said transceiver comprising a multiple-input-multiple-output transceiver.

9. A computer-implemented method, comprising:

generating a steering matrix for transmit spatial processing over a channel;

receiving explicit feedback information for said channel;

determining a delay time associated with said explicit feedback information

estimating a time constant for channel variations of said channel;

comparing said time constant with said delay time;

modifying said steering matrix with said based on said comparison.

10. The computer-implemented method of claim 9, comprising:

sending a channel state information feedback request message;

receiving a channel state information feedback response message;

retrieving from said channel state information feedback response message a time stamp for when said channel state information feedback request message was received;

retrieving a time stamp for when said channel state information feedback response message was received; and

determining said delay time using said time stamps.

11. The computer-implemented method of claim 9, comprising:

sending a channel state information feedback request message;

storing a time stamp for when said channel state information feedback request message was sent;

receiving a channel state information feedback response message corresponding to said channel state information feedback request message;

retrieving a time stamp for when said channel state information feedback response message is received; and

determining said delay time using said time stamps.

12. The computer-implemented method of claim 9, comprising modifying said steering matrix with channel state information from said explicit feedback information.

13. The computer-implemented method of claim 9, comprising:

retrieving a different steering matrix from said explicit feedback information; and

replacing said steering matrix with said different steering matrix.

14. An article comprising a machine-readable storage medium containing instructions that when executed enable a system to generate a steering matrix for transmit spatial processing over a channel, receive explicit feedback information for said channel, determine a delay time associated with said explicit feedback information, estimate a time constant for channel variations of said channel, compare said time constant with said delay time, and modify said steering matrix with said explicit feedback information based on said comparison.

15. The article of claim 14, further comprising instructions that when executed enable the system to send a channel state information feedback request message, receive a channel state information feedback response message, retrieve from said channel state information feedback response message a time stamp for when said channel state information feedback request message was received, retrieve a time stamp for when said channel state information feedback response message was received, and determine said delay time using said time stamps.

16. The article of claim 14, further comprising instructions that when executed enable the system to send a channel state information feedback request message, store a time stamp for when said channel state information feedback request message was sent, receive a channel state information feedback response message corresponding to said channel state information feedback request message, retrieve a time stamp for when said channel state information feedback response message is received, and determine said delay time using said time stamps.