Procedures to activate opportunistic relays

Patent metadata

Field	Value
Publication number	US-9265047-B2
Application number	US-201313826426-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Apr 4, 2012
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

Abstract

Aspects of the present disclosure relate to techniques for activating opportunistic relays. A combination of uplink and downlink pilots may be used to switch on user equipment relays (UeNBs) in an effort to make more accurate measurements in an effort to enable handovers. According to aspects of the present disclosure, a relay may evaluate one or more channel conditions, determine whether or not to transmit downlink reference signals to a UE based on the evaluation, and transmit downlink reference signals to the UE based on the determination. According to aspects, a relay may determine a set of resources reserved for transmission of uplink pilots by UEs, monitor the set of resources to detect transmission of uplink pilots, and report, to an eNB, a power at which the uplink pilots were received.

First claim

What is claimed is:

1. A method for wireless communication by a relay, comprising:
evaluating one or more channel conditions;
determining whether or not to transmit downlink reference signals to a user equipment (UE) based on the evaluation; and
transmitting downlink reference signals to the UE based on the determination, wherein the transmitting comprises:
selecting a reference signal (RS) configuration that is not in use by another relay, from a set of available RS configurations, wherein the selecting comprises detecting RS configurations selected by other relays and selecting an RS configuration that is not detected;
limiting transmissions on resources corresponding to non-selected RS configurations; and
transmitting RSs according to the selected RS configuration.

2. The method of claim 1 , wherein the evaluating comprises:
evaluating at least one of link quality between the relay and the UE or link quality between the relay and a donor base station.

3. The method of claim 2 , wherein the evaluating comprises:
evaluating the link quality between the relay and the UE based on an uplink reference signal transmitted from the UE.

4. The method of claim 3 , wherein the determining whether or not to transmit downlink reference signals is based, at least in part, on a type of the uplink reference signal and link quality between the donor base station and one or more relays.

5. The method of claim 3 , wherein:
the determining whether or not to transmit downlink reference signals is based, at least in part, on link quality of the UE and one or more relays; and
information regarding the link quality of the UE and one or more relays is encoded in the uplink reference signal.

6. The method of claim 3 , wherein the transmitting comprises:
transmitting the downlink reference signals to the UE if receive power of the uplink reference signal exceeds a threshold value.

7. The method of claim 1 , wherein the transmitting comprises:
transmitting channel state information RS (CSI-RS), each RS configuration comprising a CSI-RS signature that identifies a subframe and resources within the subframe for transmitting CSI-RS.

8. The method of claim 1 , further comprising:
determining the set of-available RS configurations based on a system information block (SIB) transmitted by an evolved Node B (eNB).

9. The method of claim 1 , further comprising informing an evolved Node B (eNB) of the selected RS configuration.

10. The method of claim 1 , further comprising:
initiating an activity timer in conjunction with transmitting downlink reference signals; and
ceasing transmission of downlink reference signals if the activity timer expires before handover of the UE to the relay.

11. An apparatus for wireless communication by a relay, comprising:
means for evaluating one or more channel conditions;
means for determining whether or not to transmit downlink reference signals to a user equipment (UE) based on the evaluation; and
means for transmitting downlink reference signals to the UE based on the determination, wherein the means for transmitting is configured to:
select a reference signal (RS) configuration that is not in use by another relay, from a set of available RS configurations, by detecting RS configurations selected by other relays and selecting an RS configuration that is not detected;
limit transmissions on resources corresponding to non-selected RS configurations; and
transmit RSs according to the selected RS configuration.

12. The apparatus of claim 11 , wherein the means for evaluating one or more channel conditions is configured to evaluate at least one of link quality between the relay and the UE or link quality between the relay and a donor base station.

13. The apparatus of claim 12 , wherein the means for evaluating is configured to evaluate the link quality between the relay and the UE based on an uplink reference signal transmitted from the UE.

14. The apparatus of claim 13 , wherein the means for determining whether or not to transmit downlink reference signals is based, at least in part, on a type of the uplink reference signal and link quality between the donor base station and one or more relays.

15. The apparatus of claim 13 , wherein:
the means for determining whether or not to transmit downlink reference signals is based, at least in part, on link quality of the UE and one or more relays; and
information regarding the link quality of the UE and one or more relays is encoded in the uplink reference signal.

16. The apparatus of claim 13 , wherein the means for transmitting is configured to transmit the downlink reference signals to the UE if receive power of the uplink reference signal exceeds a threshold value.

17. The apparatus of claim 11 , wherein the means for transmitting is configured to:
transmit channel state information RS (CSI-RS), each RS configuration comprising a CSI-RS signature that identifies a subframe and resources within the subframe for transmitting CSI-RS.

18. The apparatus of claim 11 , further comprising:
means for determining the set of available RS configurations based on a system information block (SIB) transmitted by an evolved Node B (eNB).

19. The apparatus of claim 11 , further comprising:
means for informing an evolved Node B (eNB) of the selected RS configuration.

20. The apparatus of claim 11 , further comprising:
means for initiating an activity timer in conjunction with transmitting downlink reference signals; and
means for ceasing transmission of downlink reference signals if the activity timer expires before handover of the UE to the relay.

21. An apparatus for wireless communication by a relay, comprising:
at least one processor configured to:
evaluate one or more channel conditions;
determine whether or not to transmit downlink reference signals to a user equipment (UE) based on the evaluation; and
transmit downlink reference signals to the UE based on the determination, wherein the at least one processor is configured is configured to transmit by:
selecting a reference signal (RS) configuration that is not in use by another relay, from a set of available RS configurations, wherein the selecting comprises detecting RS configurations selected by other relays and selecting an RS configuration that is not detected;
limiting transmissions on resources corresponding to non-selected RS configurations; and
transmitting RSs according to the selected RS configuration; and

a memory coupled to the at least one processor.

22. The apparatus of claim 21 , wherein the at least one processor is configured to evaluate one or more channel conditions by evaluating at least one of link quality between the relay and the UE or link quality between the relay and a donor base station.

23. The apparatus of claim 22 , wherein the at least one processor is configured to evaluate the link quality between the relay and the UE based on an uplink reference signal transmitted from the UE.

24. The apparatus of claim 23 , wherein the at least one processor is configured to determine whether or not to transmit the downlink reference signals is based, at least in part, on a type of the uplink reference signal and link quality between the donor base station and one or more relays.

25. The apparatus of claim 23 , wherein:
the at least one processor is configured to determine whether or not to transmit the downlink reference signals based, at least in p

Assignees

• Qualcomm Inc

Inventors

• Mallik Siddhartha
• Bhushan Naga
• Damnjanovic Aleksandar
• Somasundaram Kiran
• Stamoulis Anastasios

Classifications

• H04W72/54 Primary

  based on quality criteria · CPC title

• H04W24/02 Primary

  Arrangements for optimising operational condition · CPC title

• H04W84/047

  using dedicated repeater stations · CPC title

• H04W72/08 Primary

  Electricity · mapped topic