Wireless device, a radio node, and methods therein

Patent metadata

Field	Value
Publication number	US-11196465-B2
Application number	US-201515315330-A
Country	US
Kind code	B2
Filing date	Jan 15, 2015
Priority date	Jan 15, 2015
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

A wireless device 108 and a method therein for assisting in precoder selection for wireless communication with a Radio Node (RN) 106, and a RN 106 for performing precoder selection for wireless communication with a wireless device 108. The wireless device is configured with a set of precoders. The wireless device determines a subset of precoders out of the set of precoders; and transmits, to the RN, at least one Sounding Reference Signal (SRS) precoded with a respective at least one precoder comprised in the subset. The RN receives, from the wireless device, at least one SRS precoded with a respective at least one precoder comprised in a subset of precoders; and transmits, to the wireless device, a signal indicative of a selected precoder to be used for a transmission to the RN, wherein the selected precoder is indirectly selected based on the received at least one SRS.

First claim

The invention claimed is:

1. A method performed by a wireless device for assisting in precoder selection for wireless communication with a Radio Node (RN), the method comprising:
determining, in the wireless device, a subset of precoders out of a set of precoders configured in the wireless device and unknown to the RN; and
transmitting, to the RN, at least one sounding reference signal precoded with a respective at least one precoder comprised in the subset.

2. The method of claim 1 , further comprising:
receiving, from the RN, a signal indicative of a selected precoder to be used for a transmission to the RN, wherein the selected precoder is indirectly selected from the subset of precoders based on the transmitted at least one sounding reference signal.

3. The method of claim 2 , wherein the signal indicative of a selected precoder carries a scheduling grant for transmitting data to the RN, which scheduling grant is based on the transmitted at least one sounding reference signal, the method further comprising:
transmitting data to the RN in accordance with the scheduling grant.

4. The method of claim 1 , further comprising:
receiving, from the RN, a request for transmission of the at least one sounding reference signal by the wireless device.

5. The method of claim 1 , wherein transmitting the at least one sounding reference signal comprises:
transmitting a first sounding reference signal precoded with a specific precoder out of the respective at least one precoder in a first polarization; and
transmitting a second sounding reference signal precoded with the specific precoder in a second polarization.

6. The method of claim 1 , further comprising:
determining a number of precoders to be comprised in the subset; and
transmitting, to the RN, information about the determined number of precoders.

7. The method of claim 1 , further comprising:
receiving, from the RN, information about a number of precoders to be comprised in the subset.

8. The method of claim 1 , wherein determining the subset further comprises:
determining the subset of precoders based on a measurement on at least one transmission from the RN to the wireless device.

9. The method of claim 1 , wherein determining the subset further comprises:
receiving at least one transmission from the RN; and
determining the subset to comprise at least one precoder, which at least one precoder gives substantially the same transmit radiated energy pattern as the receive sensed energy pattern of the received at least one transmission.

10. The method of claim 1 , wherein determining the subset further comprises:
determining the subset based on knowledge about at least one preceding subset or based on a random-access procedure.

11. The method of claim 1 , wherein determining the subset further comprises:
determining a first precoder from the set of precoders to be included in the subset, which first precoder gives a received signal quality at the RN that is better than the received signal quality given by the other precoders of the set; and
determining a second precoder to be included in the subset, which second precoder is orthogonal to the first precoder.

12. The method of claim 1 , wherein determining the subset further comprises:
determining that a precoder in the set of precoders should be excluded from the subset based on a measurement of an antenna impedance, a reflected antenna power and/or of a physical interaction.

13. The method of claim 1 , further comprising:
determining that an update of the subset of precoders is needed; and
updating the subset in response to the determination.

14. The method of claim 13 , wherein updating the subset further comprises:
transmitting an update request for updating the subset of precoders to the RN in response to the wireless device determining that an update of the subset of precoders is needed.

15. The method of claim 14 , wherein updating the subset further comprises:
receiving an update response from the RN, wherein the updating of the subset is performed by the wireless device in response to receiving the update response from the RN.

16. The method of claim 13 , wherein determining that an update of the subset is needed further comprises:
receiving an update instruction from the RN instructing the wireless device to re-evaluate the subset of precoders;
re-evaluating the subset; and wherein the updating the subset further comprises:
up-dating the subset based on the re-evaluation.

17. The method of claim 16 , wherein determining that an update of the subset is needed further comprises:
transmitting a re-evaluation complete message to the RN.

18. The method of claim 16 , wherein the update instruction is received in a random access command or a handover command.

19. A method performed by a Radio Node (RN) for performing precoder selection for wireless communication with a wireless device, the method comprising:
receiving, from the wireless device, at least one sounding reference signal precoded with a respective at least one precoder comprised in a subset of precoders out of a set of precoders configured in the wireless device and unknown to the RN; and
transmitting, to the wireless device, a signal indicative of a selected precoder to be used for a transmission to the RN, wherein the selected precoder is indirectly selected from the subset of precoders based on the received at least one sounding reference signal.

20. The method of claim 19 , wherein the signal indicative of the selected precoder carries a scheduling grant for transmitting data to the RN, which scheduling grant is based on a selected one of the received at least one sounding reference signal, the method comprising:
receiving data from the wireless device in accordance with the scheduling grant.

21. The method of claim 19 , further comprising:
transmitting, to the wireless device a request for transmission, by the wireless device, of the at least one sounding reference signal.

22. The method of claim 19 , wherein receiving the at least one sounding reference signal comprises:
receiving a first sounding reference signal precoded with a specific precoder out of the respective at least one precoder in a first polarization;
receiving a second sounding reference signal precoded with the specific precoder in a second polarization; and
determining a phase angle of the second polarization relative to the first polarization based on the received first and second sounding reference signals.

23. The method of claim 19 , wherein the scheduling grant is based on the received signal quality of the received at least one sounding reference signal.

24. The method of claim 19 , further comprising:
receiving, from the wireless device, information about a number of precoders comprised in the subset.

25. The method of claim 19 , further comprising:
transmitting, to the wireless device, information about a number of precoders to be comprised in the subset.

26. The method of claim 19 , further comprising:
receiving, from the wireless device, an update request for updating the subset of precoders.

27. The method of claim 26 , further comprising:
transmitting, to the wireless device, an update response in response to the update request.

28. The method of claim 19 , further comprising:
transmitting, to the wireless device, an update instruction instru

Assignees

• Ericsson Telefon Ab L M

Inventors

• Parkvall Stefan
• Andersson Håkan
• Frenne Mattias
• Furuskog Johan

Classifications

• H04W72/23

  in the downlink direction of a wireless link, i.e. towards a terminal · CPC title

• H04W74/0833

  Random access procedures, e.g. with 4-step access · CPC title

• H04B7/0469

  taking special antenna structures, e.g. cross polarized antennas into account · CPC title

• H04B7/0456 Primary

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

• H04B7/0628

  Diversity capabilities · CPC title