SRS transmission with implied RTS/CTS

• US 10,547,422 B2
• Filed: 10/05/2017
• Issued: 01/28/2020
• Est. Priority Date: 04/13/2017
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Yoo, Taesang, Zhang, Xiaoxia, Fakoorian, Seyed Ali Akbar, Sadek, Ahmed Kamel, Mallik, Siddhartha, Kadous, Tamer
• Primary Examiner(s): Wong, Warner
• Application Number:
  US15/725,762
• Publication Number:
  US 20180302201A1
• Time in Patent Office: 845 Days
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 74/085 collision avoidance

Abstract

Sounding reference signal (SRS) transmission with implied request-to-send (RTS)/clear-to-send (CTS) operations is discussed. Two different types of SRS are defined, a legacy SRS associated with channel measurement sounding, and a contention SRS associated with contention resolution for medium sharing. The type of SRS may be distinguished based on the SRS resource associated with the particular type. Thus, legacy SRS are assigned to one SRS resource, while contention SRS are assigned to separate SRS resources. Therefore, when a neighbor node detects an SRS associated with the SRS resource for contention-type SRS, the neighbor node may know to refrain from transmission or to adjust or modify its communications depending on a spatial direction of the contention SRS.

Claims

1. A method of wireless communication, comprising:

selecting, by a base station, a sounding reference signal (SRS) type to request from a served user equipment (UE), the base station and the served UE forming a first communication pair, wherein the SRS type includes one of;

a legacy SRS associated with channel measurement sounding, or a contention SRS associated with contention resolution for medium sharing, wherein the legacy SRS is configured to cause a neighboring network node to conduct communications without modification with another network node, and wherein the contention SRS is configured to cause a neighboring network node to modify the communications with the another network node, the neighboring network node and the another network node forming a second communication pair;

determining, by the base station, an SRS resource for use by the served UE for SRS transmission, wherein the SRS resource is determined based on the served UE and the selected SRS type; and

transmitting, by the base station, an SRS request to the served UE, wherein the SRS request includes information identifying the determined SRS resource.

2. The method of claim 1, wherein the contention SRS includes one of:

a downlink contention SRS type;

an uplink contention SRS type;

or

a bi-directional contention SRS type.

3. The method of claim 2, further including:

determining, at the base station, to schedule one of;

downlink transmission from the base station, uplink transmission from the served UE, or bi-directional communication with the served UE, wherein the selecting the SRS type as the contention SRS includes;

selecting;

the downlink contention SRS type when the downlink transmission is determined;

the uplink contention SRS type when the uplink transmission is determined; and

the bi-directional contention SRS type when the bi-directional communication is determined.

4. The method of claim 1, further including:

receiving, by the base station, an SRS on the determined SRS resource from the served UE; and

determining, at the base station, to schedule data for one of;

downlink transmission from the base station, or

uplink transmission from the served UE,

during a specified period following the SRS, wherein the selecting the SRS type as the contention SRS is performed in response to the determining to schedule the data.

5. The method of claim 1, further including:

failing to receive an SRS by the base station; and

refraining, by the base station, from scheduling data communication with the served UE for a specified period.

6. The method of claim 1, further including:

determining, at the base station, no data to schedule for communication with the served UE during a specified period following the SRS, wherein the selecting the SRS type as the legacy SRS is performed in response to the determining the no data to schedule.

7. The method of claim 1, further including:

determining, by the base station, an SRS resource-type association of the SRS type to the SRS resource; and

communicating, by the base station, the SRS resource-type association with the neighboring network node.

8. The method of claim 7, further including:

communicating, by the base station, the SRS resource-type association with the served UE, wherein the SRS resource determined by the base station for the contention SRS is a common shared SRS resource shared among one or more additional served UEs.

9. A method of wireless communication, comprising:

receiving, at a user equipment (UE) from a base station, a sounding reference signal (SRS) resource-type association identifying an SRS type associated with a corresponding SRS resource, the UE and the base station forming a first communication pair, wherein the SRS type includes one of;

a legacy SRS associated with channel measurement sounding, or a contention SRS associated with contention resolution for medium sharing, wherein the legacy SRS is configured to cause a neighboring network node to conduct communications without modification with another network node, and wherein the contention SRS is configured to cause a neighboring network node to modify the communications with the another network node, the neighboring network node and the another network node forming a second communication pair;

receiving, at the UE, an SRS request from a serving base station, wherein the SRS request contains information identifying an SRS resource for SRS transmission; and

transmitting, by the UE, an SRS on the SRS resource identified in the SRS request.

10. The method of claim 9, further including:

receiving, at the UE, configuration of one or more SRS resources, wherein the SRS resource is one of the one or more SRS resources.

11. The method of claim 9, further including:

determining, by the UE, the SRS type based on the SRS resource and the SRS resource-type association.

12. The method of claim 11, further including:

assuming, by the UE, that no communication with the serving base station will occur for a specified period following transmission of a legacy SRS.

13. The method of claim 12, further including:

switching, by the UE, to a sleep mode during the specified period.

14. The method of claim 11, further including:

determining, by the UE, a subtype of the contention SRS based on the SRS resource and the SRS resource-type association, wherein the subtype includes one of;

a downlink contention SRS type, an uplink contention SRS type, or a bi-directional contention SRS type.

15. The method of claim 14, further including:

assuming, by the UE, that communication with the serving base station for a specified period following transmission of the SRS is restricted to one of;

downlink only, uplink only, or bi-direction as indicated by the subtype of the contention SRS.

16. The method of claim 9, further including:

detecting, by the UE in response to the SRS request requesting the contention SRS of a downlink contention SRS type, that a shared spectrum of the UE is unoccupied for reception, wherein the transmitting the SRS is performed in response to the detecting the shared spectrum is unoccupied.

17. The method of claim 9, further including:

detecting, by the UE in response to the SRS request requesting a contention SRS of a downlink contention SRS type, that a shared spectrum of the UE is occupied for reception; and

refraining from the transmitting the SRS in response to the detecting the shared spectrum is occupied.

18. The method of claim 9, further including:

detecting, by the UE in response to the SRS request requesting a contention SRS of an uplink contention SRS type, that a shared spectrum of the UE is unoccupied for transmission, wherein the transmitting the SRS is performed in response to the detecting the shared spectrum is unoccupied.

19. The method of claim 9, further including:

detecting, by the UE in response to the SRS request requesting a contention SRS of an uplink contention SRS type, that a shared spectrum of the UE is occupied for transmission; and

refraining from the transmitting the SRS in response to the detecting the shared spectrum is occupied.

20. The method of claim 9, wherein the transmitting the SRS as a contention SRS associated with contention resolution for medium sharing is according to one of:

a first power that is different from a second power associated with transmission of a legacy SRS associated with channel measurement sounding; and

a first timing that is different from a second timing used with transmission of a legacy SRS associated with channel measurement sounding.

21. The method of claim 20, wherein the first power and the second power are determined based on one or more of:

different rules, or separate power control commands, and wherein the first timing and the second timing are determined based on one of;

different rules, or separate timing advance commands.

22. A method of wireless communications, comprising:

detecting, at a network node, one or more sounding reference signals (SRS) from one or more non-served user equipment (UE);

determining, by the network node, whether the one or more SRS correspond to one of;

legacy SRS associated with channel measurement sounding, or contention SRS associated with contention resolution for medium sharing, wherein the determining is based on an SRS resource carrying the one or more SRS;

conducting communications without modification, by the network node, with another network node based on determining the one or more SRS correspond to the legacy SRS; and

modifying communications, by the network node, with the another network node based on determining the one or more SRS correspond to the contention SRS.

23. The method of claim 22, wherein the modifying communications includes one of:

refraining, by the network node, from any communications with the another network node for a predetermined period of time;

beamforming, by the network node, the communications with the another network node to create a spatial null in a spatial direction of the contention SRS;

or

communicating, by the network node, with the another network node when the another network node is located in a different spatial direction than the spatial direction of the contention SRS.

24. The method of claim 22, further including:

determining, by the network node, a type association identifying an association of an SRS type of one of;

a contention type SRS or a legacy type SRS, with a corresponding SRS resource, wherein the determining is based on the type association and the SRS resource; and

transmitting, by the network node, the type association to one or more neighboring base stations.

25. The method of claim 22, further including:

receiving, by the network node from one or more neighboring network nodes, a SRS resource-type association identifying an SRS type associated with the SRS resource, wherein the SRS type includes one of;

a legacy SRS associated with channel measurement sounding, or a contention SRS associated with contention resolution for medium sharing.

26. The method of claim 25, wherein determining SRS type is based on the SRS resource and the SRS resource-type association.

27. The method of claim 26, wherein the modifying communications includes:

estimating, by the network node, that the communications with the another network node does not interfere in a spatial direction of the contention SRS when the SRS resource is identified as associated with the downlink transmission grant; and

transmitting downlink signals from the network node to the another network node.

28. The method of claim 26, wherein the modifying communications includes:

estimating, by the network node, that the communications with the another network node is in another spatial direction from the contention SRS when the SRS resource is identified as associated with the uplink transmission grant; and

receiving uplink signals at the network node from the another network node.

29. The method of claim 22, wherein the determining the one or more SRS corresponds to the contention SRS includes identifying, by the network node, the SRS resource is associated with carrying a contention type SRS.

30. The method of claim 22, wherein the detecting the one or more SRS includes:

measuring, by the network node, a total received energy level of the one or more SRS corresponding to the contention SRS, wherein the one or more SRS corresponding to the contention SRS are detected on a single SRS resource.