Techniques for beam shaping at a millimeter wave base station and a wireless device and fast antenna subarray selection at a wireless device

Patent metadata

Field	Value
Publication number	US-9872296-B2
Application number	US-201514822681-A
Country	US
Kind code	B2
Filing date	Aug 10, 2015
Priority date	Jan 6, 2015
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

Methods, systems, and devices are described for wireless communication at a user equipment (UE). A wireless communications system may improve UE discovery latency by dynamically selecting and switching beam forming codebooks at the millimeter wave base station and the wireless device. Selecting an optimal beam forming codebook may allow the wireless communication system to improve link margins between the base station without compromising resources. In some examples, a wireless device may determine whether the received signals from the millimeter wave base station satisfy established signal to noise (SNR) thresholds, and select an optimal beam codebook to establish communication. Additionally or alternately, the wireless device may further signal the selected beam codebook to the millimeter wave base station and direct the millimeter wave base station to adjust its codebook based on the selection.

First claim

What is claimed is:

1. A method of communications at a wireless device, the method comprising:
receiving, at the wireless device, a first signal from a millimeter wave base station, the first signal beamformed on a plurality of beamforming vectors from a first codebook;
scanning a plurality of antenna subarrays, each of the plurality of antenna subarrays comprising a different subset of a plurality of antennas of the wireless device, to identify a quality of the first signal as received by each of the plurality of antenna subarrays; and
selecting one of the plurality of antenna subarrays based at least in part on the identified quality of the first signal as received by at least one of the plurality of antenna subarrays.

2. The method of claim 1 , wherein the scanning further comprises:
scanning the plurality of antenna subarrays with a plurality of beamforming vectors from a subarray selection codebook to identify the quality of the first signal as received by each of the plurality of antenna subarrays.

3. The method of claim 2 , further comprising:
selecting a first beamforming vector from the plurality of beamforming vectors from the subarray selection codebook for a respective subarray from the plurality of antenna subarrays based at least on the identified quality of the first signal.

4. The method of claim 2 , wherein the subarray selection codebook comprises at least one of:
a pseudo-omni beam pattern codebook;
an antenna selection codebook;
a coarse codebook;
an intermediate codebook;
a fine codebook;
a codebook designed to mitigate near-field impairments;
a codebook designed to assist in channel estimation; or
a codebook designed to assist in radio-frequency design, reduce system complexity, or reduce system cost; or
a combination of beamforming vectors from different codebooks.

5. The method of claim 1 , further comprising:
initiating an on-demand search to identify a second beamforming vector from a plurality of beamforming vectors at the millimeter wave base station, wherein the second beamforming vector is identified from a group comprising at least one of a coarse codebook, an intermediate codebook, a fine codebook, a near-field impairment mitigation codebook, a channel estimation codebook, a complexity reduction codebook, or a wireless device specific codebook.

6. The method of claim 1 , further comprising:
determining whether the quality of the first signal at the selected antenna subarray is above or below a first threshold; and
transmitting a second signal to the millimeter wave base station based at least in part on the determining.

7. The method of claim 6 , further comprising:
receiving, at the wireless device, a third signal from the millimeter wave base station, the third signal beamformed on a plurality of beamforming vectors from a second codebook;
scanning a plurality of beamforming vectors from the second codebook; and
identifying a second beamforming vector from a plurality of beamforming vectors from the second codebook based at least in part on the scanning a plurality of beamforming vectors from the second codebook.

8. The method of claim 6 , further comprising:
adapting the first threshold based at least in part on a selection of a beamforming vector by the wireless device.

9. The method of claim 6 , further comprising:
transmitting the second signal via a random access channel (RACH).

10. The method of claim 6 , further comprising:
determining that a signal quality of the first signal at the selected subarray is below the first threshold; and
transmitting the second signal over a low-frequency carrier network coexisting with a millimeter wave carrier network based at least in part on determining that the signal quality of the first signal at the selected subarray is below the first threshold.

11. The method of claim 6 , further comprising:
transmitting the second signal via a highly-coded low-rate communication link already established with a unique identification.

12. The method of claim 6 , wherein the second signal comprises a signal energy estimate, a beamforming vector index, information for beamforming, or a combination thereof.

13. The method of claim 6 , further comprising:
calculating a signal-to-noise ratio of the first signal to determine the quality of the first signal.

14. The method of claim 1 , wherein the first signal is a directional primary synchronization signal.

15. An apparatus for wireless communications, comprising:
a processor;
memory in electronic communication with the processor; and
instructions stored in the memory; wherein the instructions are executable by the processor to:
receive, at a wireless device, a first signal from a millimeter wave base station, the first signal beamformed on a plurality of beamforming vectors from a first codebook;
scan a plurality of antenna subarrays, each of the plurality of antenna subarrays comprising a different subset of a plurality of antennas of the wireless device, to identify a quality of the first signal as received by each of the plurality of antenna subarrays; and
select one of the plurality of antenna subarrays based at least in part on the identified quality of the first signal as received by at least one of the plurality of antenna subarrays.

16. The apparatus of claim 15 , wherein the instructions are executable by the processor to:
scan the plurality of antenna subarrays with a plurality of beamforming vectors from a subarray selection codebook to identify the quality of the first signal as received by each of the plurality of antenna subarrays.

17. The apparatus of claim 16 , wherein the instructions are executable by the processor to:
select a first beamforming vector from the plurality of beamforming vectors from the subarray selection codebook for that subarray from the scanned portion of the plurality of antenna subarrays based at least on the identified quality of the first signal.

18. The apparatus of claim 16 , wherein the subarray selection codebook comprises at least one of:
a pseudo-omni beam pattern codebook;
an antenna selection codebook;
a coarse codebook;
an intermediate codebook;
a fine codebook;
a codebook designed to mitigate near-field impairments;
a codebook designed to assist in channel estimation;
a codebook designed to assist in radio-frequency design, reduce system complexity, or reduce system cost;
or a combination of beamforming vectors from different codebooks.

19. The apparatus of claim 15 , wherein the instructions are executable by the processor to:
initiate an on-demand search to identify a second beamforming vector from a plurality of beamforming vectors at the millimeter wave base station, wherein the second beamforming vector is identified from a group comprising at least one of a coarse codebook, an intermediate codebook, a fine codebook, a near-field impairment mitigation codebook, a channel estimation codebook, a complexity reduction codebook, or a wireless device specific codebook.

20. The apparatus of claim 15 , wherein the instructions are executable by the processor to:
determine whether the quality of the first signal at the selected antenna subarray is above or below a first threshold; and
transmit a second signal to the millimeter wave base station based at least in part on the determining.

21. The apparatus of claim 20 , wherein the instructions are executable by the processor to:
receive, at the wireless device, a third signal from the millimeter wave base stat

Assignees

• Qualcomm Inc

Inventors

• Raghavan Vasanthan
• Cezanne Juergen
• Subramanian Sundar
• Sampath Ashwin
• Li Junyi

Classifications

• H04W72/542

  using measured or perceived quality · CPC title

• H04B7/0617

  for beam forming · CPC title

• H04B7/0639 Primary

  Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection · CPC title

• H04B7/0456 Primary

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

• H04W72/0466 Primary

  the resource being a scrambling code · CPC title