Mobility-resilient multi-antenna communications

Patent metadata

Field	Value
Publication number	US-9031162-B2
Application number	US-201113339971-A
Country	US
Kind code	B2
Filing date	Dec 29, 2011
Priority date	Dec 29, 2011
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

The antenna weight selection solution disclosed herein selects antenna weights for a multiple antenna communication system that transmits uplink or downlink data using multiple radiation patterns based on channel variability metrics determined for two or more sets of candidate antenna weights. In so doing the antenna weight selection solution disclosed herein reduces the channel variability associated with data transmissions, and therefore reduces the amount of feedback and/or the feedback rates required for the multiple antenna communication system.

First claim

What is claimed is:

1. An antenna weight selector for transmitting data in a communication system from a transmitting node having multiple transmission antenna elements to a receiving node, the antenna weight selector comprising:
a channel variability processor configured to determine a channel variability metric for each of two or more sets of candidate antenna weights corresponding to two or more candidate radiation patterns; and
a selection processor configured to select, from the two or more sets of candidate antenna weights, at least one set of antenna weights for transmitting data to at least one receiving node based on the determined channel variability metrics;
wherein the selection processor comprises a transmission rank selector configured to determine a number of candidate sets of antenna weights satisfying a channel variability requirement and to select at least one transmission rank based on the number, said at least one transmission rank representing a number of data signals to be transmitted simultaneously from the transmitting node to at least one receiving node.

2. The antenna weight selector of claim 1 wherein the selection processor is configured to select the at least one set of antenna weights having the lowest channel variability metric.

3. The antenna weight selector of claim 1 wherein the selection processor is configured to select the at least one set of antenna weights having the channel variability metric below a threshold.

4. The antenna weight selector of claim 1 wherein the selection processor comprises a quality processor configured to determine a signal quality metric corresponding to one or more transmitted signals, and wherein the selection processor is further configured to select the at least one set of antenna weights based on the signal quality metrics and the channel variability metrics.

5. The antenna weight selector of claim 4 wherein the selection processor selects the at least one set of antenna weights by ranking the candidate sets of antenna weights based on the one or more signal quality metrics and selecting the at least one set of the highest ranked candidate sets of antenna weights according to the ranking based on the channel variability metrics.

6. The antenna weight selector of claim 1 wherein the selection processor selects the at least one set of antenna weights by selecting at least one pre-coder index from a codebook based on the determined channel variability metrics, where each pre-coder index in the codebook corresponds to one of the candidate sets of antenna weights.

7. The antenna weight selector of claim 1 wherein the channel variability processor determines the channel variability metric for each set of candidate antenna weights based on corresponding channel estimates determined for each effective channel, each of said effective channels representing a combination of a wireless channel from each of a plurality of transmit antenna elements to the receiving node, wherein each of the wireless channels are weighted by the corresponding antenna weight.

8. The antenna weight selector of claim 1 wherein the channel variability metric comprises one of a time variability metric representing the time variability of corresponding wireless communication channels, a frequency variability metric representing the frequency variability of the corresponding wireless communication channels, and a combined variability metric derived from the time and frequency variability metrics.

9. The antenna weight selector of claim 1 wherein the selection processor is further configured to select one or more receiving nodes to receive transmitted data based on the channel variability metric in cooperation with a user selection metric.

10. The antenna weight selector of claim 1 wherein the selection processor comprises a cost processor configured to determine a performance cost associated with each of the candidate sets of antenna weights, and wherein the selection processor selects the at least one set of antenna weights based on the determined performance costs and the channel variability metrics.

11. The antenna weight selector of claim 1 wherein the channel variability processor and the selection processor are distributed between multiple network nodes, wherein the selection processor comprises a receiver configured to receive the channel variability metric determined for each of the sets of candidate antenna weights from at least one other network node.

12. The antenna weight selector of claim 1 wherein the channel variability processor and the selection processor are distributed between multiple network nodes, wherein the channel variability processor is further configured to select two or more preliminary sets of candidate antenna weights for the transmitting node based on the determined channel variability metrics, wherein the selection processor comprises a receiver configured to receive the two or more preliminary sets of antenna weights from at least one other network node, and wherein the selection processor selects the at least one set of antenna weights for transmitting data from the two or more preliminary sets of antenna weights received from the at least one other network node.

13. The antenna weight selector of claim 1 wherein the channel variability processor and the selection processor are co-located in a network node.

14. A method of selecting antenna weights to be used for transmitting data in a communication system from a transmitting node having multiple transmission antenna elements to a receiving node, the method comprising:
determining a channel variability metric for each of two or more sets of candidate antenna weights corresponding to two or more candidate radiation patterns;
selecting, from the two or more sets of candidate antenna weights, at least one set of antenna weights for transmitting data to at least one receiving node based on the determined channel variability metrics;
transmitting data to said at least one receiving node using the selected antenna weights for each transmission; and
determining a number of candidate sets of antenna weights satisfying a channel variability requirement, and selecting a transmission rank based on the number, said transmission rank representing a number of data signals to be transmitted simultaneously from the transmitting node.

15. The method of claim 14 wherein selecting the at least one set of antenna weights comprises selecting the at least one set of antenna weights having the lowest channel variability metric.

16. The method of claim 14 wherein selecting the at least one set of antenna weights comprises selecting the at least one set of antenna weights having a channel variability metric below a threshold.

17. The method of claim 14 further comprising determining a signal quality metric corresponding to one or more transmitted signals, wherein selecting the at least one set of antenna weights comprises selecting the at least one set of antenna weights based on the signal quality metrics and the channel variability metrics.

18. The method of claim 17 further comprising ranking the candidate sets of antenna weights based on the one or more signal quality metrics, wherein selecting the at least one set of antenna weights comprises selecting the at least one set of the highest ranked candidate sets of antenna weights based on the channel variability metrics.

19. The method of claim 14 wherein selecting the at least one set of antenna weights comprises selecting at least one pre-coder index from a codebook based on the determined

Assignees

• Asplund Henrik
• Balachandran Kumar
• Selén Yngve
• Ericsson Telefon Ab L M

Inventors

• Asplund Henrik
• Balachandran Kumar
• Selén Yngve

Classifications

• H04B7/0658

  Feedback reduction · CPC title

• H04B7/0619

  using feedback from receiving side (feedback signaling for adaptive modulation/coding H04L1/0001) · CPC title

• H04B7/0456 Primary

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04B7/0617

  for beam forming · CPC title