Changing cyclic prefix (CP) length based on precoder mode selection

Patent metadata

Field	Value
Publication number	US-10237103-B2
Application number	US-201615078087-A
Country	US
Kind code	B2
Filing date	Mar 23, 2016
Priority date	Nov 24, 2015
Publication date	Mar 19, 2019
Grant date	Mar 19, 2019

Abstract

Aspects provide for selecting a precoder mode for a transmission, changing a cyclic prefix (CP) length based on the selected precoder mode, and transmitting a signal that includes the changed CP length. Changing the CP length may involve using the selected precoder mode to lookup a value by which to change a nominal CP length. After changing the CP length, information indicating the changed CP length may be transmitted to a receiver of the signal. Precoder mode selection may be based on feedback information that indicates whether a receiver requests a change to the CP length. Precoder mode selection may be based on a received reference signal that indicates a condition of a communication channel. The reference signal may be used to select the precoder mode that results in the smallest relative delay spread, the largest relative delay spread compression, the largest relative beamforming gain, and/or the largest relative throughout.

First claim

The invention claimed is:

1. A method of wireless communication, the method comprising:
transmitting a first signal having a first cyclic prefix (CP) length over a communication channel, wherein the first CP length is based on a first precoder mode;
receiving a reference signal indicating a condition of the communication channel;
selecting a second precoder mode for transmission of a second signal, wherein the selection is based on the received reference signal, and wherein the second precoder mode results in a compressed delay spread relative to another delay spread of the first precoder mode;
changing the first CP length to a second CP length, the second CP length based on the selected second precoder mode; and
transmitting the second signal having the second CP length over the communication channel.

2. The method of claim 1 , wherein changing the first CP length comprises:
using the selected second precoder mode to lookup a value indicative of the second CP length by which to change the first CP length.

3. The method of claim 1 , further comprising:
after changing the first CP length, transmitting information indicating the change to a receiver of the first signal.

4. The method of claim 1 , further comprising:
after selecting the second precoder mode, transmitting information indicating the selected second precoder mode to a receiver of the signal.

5. The method of claim 1 , wherein selecting the second precoder mode comprises:
receiving feedback information from a receiver of the signal, wherein the feedback information indicates whether the receiver requests the change from the first CP length to the second CP length; and
selecting the second precoder mode based on the feedback information.

6. The method of claim 1 , wherein selecting the second precoder mode comprises:
receiving a reference signal indicating a condition of a communication channel; and
based on the received reference signal, selecting the second precoder mode, wherein the second precoder mode results in a beamforming gain.

7. The method of claim 1 , wherein selecting the precoder mode comprises:
receiving a reference signal indicating a condition of a communication channel; and
based on the received reference signal, selecting the second precoder mode, wherein the second precoder mode results in a maximized throughout over the communication channel.

8. The method of claim 1 , wherein the second signal is precoded using the second precoder mode.

9. The method of claim 1 , further comprising determining a delay spread based on one or more parameters indicating a condition of a communication channel, wherein selection of the second precoder mode is based on the delay spread.

10. An apparatus configured for wireless communication, the apparatus comprising:
a transceiver;
a memory; and
at least one processor communicatively coupled to the transceiver and the memory, wherein the at least one processor is configured to:
transmit a first signal having a first cyclic prefix (CP) length over a communication channel, wherein the first CP length is based on a first precoder mode,
receive a reference signal indicating a condition of the communication channel,
select a second precoder mode for transmission of a second signal, wherein the selection is based on the received reference signal, and wherein the second precoder mode results in a compressed delay spread relative to another delay spread of the first precoder mode,
change the first CP length to a second CP length, the second CP length based on the selected second precoder mode, and
transmit the second signal having the second CP length over the communication channel.

11. The apparatus of claim 10 , wherein change of the CP length comprises:
using the selected second precoder mode to lookup a value indicative of the second CP length by which to change the first CP length.

12. The apparatus of claim 10 , wherein the at least one processor is further configured to:
after the change of the first CP length, transmit information indicating the change to a receiver of the first signal.

13. The apparatus of claim 10 , wherein the at least one processor is further configured to:
after the selection of the second precoder mode, transmit information indicating the selected second precoder mode to a receiver of the signal.

14. The apparatus of claim 10 , wherein selection of the second precoder mode comprises:
receiving feedback information from a receiver of the signal, wherein the feedback information indicates whether the receiver requests the change from the first CP length to the second CP length; and
selecting the second precoder mode based on the feedback information.

15. The apparatus of claim 10 , wherein selection of the second precoder mode comprises:
receiving a reference signal indicating a condition of a communication channel; and
based on the received reference signal, selecting the second precoder mode, wherein the second precoder mode results in a beamforming gain.

16. The apparatus of claim 10 , wherein selection of the precoder mode comprises:
receiving a reference signal indicating a condition of a communication channel; and
based on the received reference signal, selecting the second precoder mode, wherein the second precoder mode results in a maximized throughout over the communication channel.

17. The apparatus of claim 10 , wherein the second signal is precoded using the second precoder mode.

18. An apparatus for wireless communication, the apparatus comprising:
means for transmitting a first signal having a first cyclic prefix (CP) length over a communication channel, wherein the first CP length is based on a first precoder mode;
means for receiving a reference signal indicating a condition of the communication channel;
means for selecting a second precoder mode for transmission of a second signal, wherein the selection is based on the received reference signal, and wherein the second precoder mode results in a compressed delay spread relative to another delay spread of the first precoder mode;
means for changing the first CP length to a second CP length, the second CP length based on the selected second precoder mode; and
means for transmitting the second signal having the second CP length over the communication channel.

19. The apparatus of claim 18 , wherein the means for changing the first CP length is configured to:
use the selected second precoder mode to lookup a value indicative of the second CP length by which to change the first CP length.

20. The apparatus of claim 18 , further comprising:
means for transmitting information indicating the change to a receiver of the first signal after changing the first CP length.

21. The apparatus of claim 18 , further comprising:
means for transmitting information indicating the second precoder mode to a receiver of the first signal after selecting the second precoder mode.

22. The apparatus of claim 18 , wherein the second signal is precoded using the second precoder mode.

23. A non-transitory computer-readable medium storing computer-executable code comprising instructions configured to:
transmit a first signal having a first cyclic prefix (CP) length over a communication channel, wherein the first CP length is based on a first precoder mode;
receive a reference signal indicating a condition of the communication channel;
select a second precoder mode for transmission of a second signal, wherein the selection

Assignees

• Qualcomm Inc
• Qualcom Incorporated

Inventors

• Manolakos Alexandros
• Ji Tingfang
• Namgoong June
• Soriaga Joseph Binamira

Classifications

• H04L5/0026

  Division using four or more dimensions, e.g. beam steering or quasi-co-location [QCL] · CPC title

• H04B7/0482

  Adaptive codebooks · CPC title

• H04L5/0016

  Time-frequency-code · CPC title

• H04B7/0619

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

• H04L27/2607 Primary

  Cyclic extensions · CPC title