Wi-Fi adaptive transmit antenna selection

Patent metadata

Field	Value
Publication number	US-9768825-B2
Application number	US-201514871756-A
Country	US
Kind code	B2
Filing date	Sep 30, 2015
Priority date	Nov 3, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

Wireless communication devices (UEs) may include multiple receive (RX) chains and associated antennas, and at least one transmit (TX) chain co-located with one of the RX chains. The UE may track instant fading of the antenna gain(s) during reception of packets from an associated access point (AP) device to which the UE intends to transmit packets. The UE may also track long term antenna gain(s), using any packets received at the multiple RX chains within the UE. At a switching occasion, a decision is made by the UE whether to switch antennas. If the instant fading detection is based on packets received no later than a specified time period prior to the switching occasion, then the UE may make the switching decision based on the results of the instant fading tracking. Otherwise, the UE may make the switching decision based on the results of the long term antenna gain tracking.

First claim

The invention claimed is:

1. A wireless communication device comprising:
a plurality of antennas configured to transmit and receive signals;
a plurality of receive (RX) chains corresponding to the plurality of antennas and configured to receive RX signals from the plurality of antennas;
a transmit (TX) chain co-located with a first RX chain of the plurality of RX chains and configured to provide TX signals to the plurality of antennas; and
a processing element configured to interoperate with at least the plurality of RX chains to cause the wireless communication device to:
track instant changes in respective gain performance of at least two antennas of the plurality of antennas during operation of respective RX chains of the plurality of RX chains interoperating with the at least two antennas;
track respective long term gains of the at least two antennas during operation of the respective RX chains; and
determine, at a switching occasion, which antenna of the at least two antennas to select for use when transmitting TX packets via the TX chain, responsive to one of:
first information corresponding to the tracked instant changes; or
second information corresponding to the tracked respective long term gains.

2. The wireless communication device of claim 1 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
when determining which antenna of the at least two antennas to use, select which one of the first information and the second information is used responsive to when a most recent RX packet was received during the tracking of the instant changes with respect to the switching occasion.

3. The wireless communication device of claim 2 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
select the first information when the most recent RX packet prior to the switching occasion is received within a specified time period and not earlier.

4. The wireless communication device of claim 2 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
select the second information when the most recent RX packet prior to the switching occasion is received earlier than a specified point in time.

5. The wireless communication device of claim 1 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
track the instant changes during operation of the respective RX chains based on packets received from a specific access point (AP) device in communication with the wireless communication device.

6. The wireless communication device of claim 1 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
when using the first information, determine which antenna to select based on:
a threshold obtained from a sum of a prediction error margin; and
a gain difference between the at least two antennas.

7. The wireless communication device of claim 1 , wherein the processing element is configured to interoperate with at least the plurality of RX chains to further cause the wireless communication device to:
when using the second information, determine which antenna to select based on a threshold obtained from a sum of:
a difference in average gain between the at least two antennas: and
a threshold difference adapted to a sample interval between reception of subsequent RX packets.

8. An apparatus comprising:
a processing element configured to:
track instant changes in respective gain performance of at least two antennas of a plurality of antennas during operation of respective RX chains of a plurality of RX chains interoperating with the at least two antennas, wherein a transmit (TX) chain is co-located with a first RX chain of the plurality of RX chains and is configured to provide TX signals to the at least two antennas;
track respective long term gains of the at least two antennas during operation of the respective RX chains; and
determine, at a switching occasion, which antenna of the at least two antennas to select for use when transmitting TX packets via the TX chain interoperating with the at least two antennas, responsive to one of:
first information corresponding to the tracked instant changes; or
second information corresponding to the tracked respective long term gains.

9. The apparatus of claim 8 , wherein the processing element is further configured to:
when determining which antenna of the at least two antennas to use, select which one of the first information and the second information is used responsive to when a most recent RX packet was received during the tracking of the instant changes with respect to the switching occasion.

10. The apparatus of claim 9 , wherein the processing element is further configured to:
select the first information when the most recent RX packet prior to the switching occasion is received within a specified time period and not earlier.

11. The apparatus of claim 9 , wherein the processing element is further configured to:
select the second information when the most recent RX packet prior to the switching occasion is received earlier than a specified point in time.

12. The apparatus of claim 8 , wherein the processing element is further configured to:
track the instant changes during operation of the respective RX chains based on packets received from a specific access point (AP) device in communication with the wireless communication device.

13. The apparatus of claim 8 , wherein the processing element is further configured to:
when using the first information, determine which antenna to select based on:
a threshold obtained from a sum of a prediction error margin; and
a gain difference between the at least two antennas.

14. The apparatus of claim 8 , wherein the processing element is further configured to:
when using the second information, determine which antenna to select based on a threshold obtained from a sum of:
a difference in average gain between the at least two antennas: and
a threshold difference adapted to a sample interval between reception of subsequent RX packets.

15. A non-volatile memory device storing instructions executable by a processing element to cause a wireless communication device to:
track instant changes in respective gain performance of at least two antennas of a plurality of antennas comprised in the wireless communication device during operation of respective RX chains of a plurality of RX chains comprised in the wireless communication device and interoperating with the at least two antennas;
track respective long term gains of the at least two antennas during operation of the respective RX chains; and
determine, at a switching occasion, which antenna of the at least two antennas to select for use when transmitting TX packets via a TX chain collocated with one of the plurality of RX chains in the wireless communication device and interoperating with the at least two antennas, responsive to one of:
first information corresponding to the tracked instant changes; or
second information corresponding to the tracked respective long term gains.

16. The non-volatile memory device of claim 15 , wherein the instructions are executable by the processing element to further cause the wireless

Assignees

• Apple Inc

Inventors

• Wang Xiaowen
• Mujtaba Syed Aon
• Majjigi Vinay R
• Kim Joonsuk

Classifications

• H04B1/40 Primary

  Circuits · CPC title

• H04W88/08

  Access point devices · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04B7/0817

  with multiple receivers and antenna path selection · CPC title

• H04B7/061

  using feedback from receiving side · CPC title