Channel quality index feedback reduction for broadband systems

• US 9,577,730 B2
• Filed: 09/04/2015
• Issued: 02/21/2017
• Est. Priority Date: 03/16/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kotecha, Jayesh H.
• Primary Examiner(s): Rizk, Sam
• Application Number:
  US14/845,506
• Publication Number:
  US 20160043788A1
• Time in Patent Office: 536 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• 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 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

A system and methodology for exploiting channel correlation in time and/or frequency to reduce CQI feedback in wireless communications systems. By compressing CQI feedback at the receiver to reduce redundancy in CQI feedback information that results from the channel correlation, the average feedback rate is reduced. Redundancy in time may be removed from the CQI feedback by monitoring variations of the CQI information in time at the receiver so that a codebook index for a given reporting instance is communicated to the transmitter only if it differs from the codebook index for the previous reporting instance. Otherwise, no feedback is performed.

Claims

1. An apparatus, comprising:

one or more processing elements configured to;

determine channel state information for wireless communications;

determine a plurality of codebook indices corresponding to the determined channel state information;

in response to determining that one or more of the codebook indices did not change relative to a previous transmission of channel state information, generate a compressed set of channel state information that omits the one or more of the codebook indices that did not change relative to the previous transmission of channel state information; and

transmit the compressed set of channel state information.

2. The apparatus of claim 1, wherein the channel state information includes channel matrix information for the wireless communications.

3. The apparatus of claim 1, wherein the channel state information includes one or more signal to noise ratios.

4. The apparatus of claim 1, wherein the compressed set of channel state information is usable to select an adaptive modulation and coding scheme for subsequent wireless communications.

5. The apparatus of claim 1, wherein the compressed set of channel state information includes only transmission channel state information that meets predetermined selection metrics.

6. The apparatus of claim 1, wherein the compressed set of channel state information includes one or more codebook indices.

7. A method, comprising:

receiving a compressed set of channel state information, wherein the compressed set of channel state information includes one or more codebook indices that changed relative to a previous transmission of channel state information and omits one or more codebook indices that did not change relative to the previous transmission;

determining the omitted indices based on the previous transmission; and

selecting an adaptive coding and modulation scheme based on the received codebook indices and determined omitted indices.

8. The method of claim 7, wherein the channel state information includes channel matrix information.

9. The method of claim 7, wherein the channel state information includes one or more signal to noise ratios.

10. The method of claim 7, wherein the channel state information corresponds to multiple-input multiple-output (MIMO) communications.

11. The method of claim 7, wherein the compressed set of channel state information includes only channel state information that meets predetermined selection metrics.

12. The method of claim 7, wherein the compressed set of channel state information includes one or more codebook indices.

13. An apparatus, comprising:

at least one radio;

a plurality of antennas coupled to the at least one radio; and

one or more processing elements configured to;

receive a compressed set of channel state information, wherein the compressed set of channel state information includes one or more codebook indices that changed relative to a previous transmission of channel state information and omits one or more codebook indices that did not change relative to the previous transmission;

determine the omitted indices based on the previous transmission; and

select an adaptive coding and modulation scheme based on the received codebook indices and determined omitted indices.

14. The apparatus of claim 13, wherein the channel state information includes channel matrix information.

15. The apparatus of claim 13, wherein the channel state information includes one or more signal to noise ratios.

16. The apparatus of claim 13, wherein the channel state information is for a multiple-input multiple-output (MIMO) channel.

17. The apparatus of claim 13, wherein the compressed set of channel state information includes only channel state information that meets predetermined selection metrics.

18. The apparatus of claim 13, wherein the compressed set of channel state information includes one or more codebook indices.