Uplink listen before talk operation

Patent metadata

Field	Value
Publication number	US-2016309498-A1
Application number	US-201615077587-A
Country	US
Kind code	A1
Filing date	Mar 22, 2016
Priority date	Apr 20, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

Methods, systems, and devices for wireless communication are described. A wireless device may determine whether a source carrier for an uplink grant is in licensed or unlicensed spectrum and then select a listen-before-talk (LBT) procedure for accessing a shared spectrum channel. For example, the device may select one range parameter (e.g., q value) for a backoff procedure of a clear channel assessment (CCA) if the source carrier is in unlicensed spectrum, and a different (e.g., larger) range parameter if the source carrier is in licensed spectrum. In some cases, the device may operate in a stand-alone operating mode and the source carrier may be identified based on the mode. In some cases, the device may receive signaling that indicates a carrier configuration, and may select the LBT procedure based on whether a carrier configured on unlicensed spectrum is self-scheduled or cross-carrier scheduled.

First claim

What is claimed is:

1 . A method for wireless communications, comprising:
identifying a source carrier for an uplink grant; and determining a listen-before-talk (LBT) procedure for accessing a channel of a shared spectrum based at least in part on the source carrier for the uplink grant.

2 . The method of claim 1 , wherein determining the LBT procedure comprises:
determining a clear channel assessment (CCA) period based at least in part on the source carrier for the uplink grant.

3 . The method of claim 2 , wherein the CCA period comprises a first duration if the source carrier is in a shared spectrum and the CCA period comprises a second duration if the source carrier is in a licensed spectrum, wherein the second duration is greater than the first duration.

4 . The method of claim 1 , wherein determining the LBT procedure comprises:
determining a CCA procedure based at least in part on the source carrier for the uplink grant.

5 . The method of claim 4 , wherein the determined CCA procedure comprises a CCA procedure without a backoff procedure.

6 . The method of claim 4 , wherein the determined CCA procedure comprises a linear random or an exponential backoff procedure.

7 . The method of claim 6 , wherein the determined CCA procedure further comprises:
determining an LBT priority class for the exponential backoff procedure.

8 . The method of claim 6 , further comprising:
selecting a first range parameter for the backoff procedure if the source carrier is in a shared spectrum; and selecting a second range parameter for the backoff procedure if the source carrier is in a licensed spectrum, wherein the second range parameter is greater than the first range parameter, wherein the first range parameter and the second range parameter are different from a range parameter associated with a base station from which the uplink grant is received.

9 . The method of claim 1 , wherein identifying the source carrier for the uplink grant comprises:
identifying a carrier in the shared spectrum.

10 . The method of claim 9 , further comprising:
determining that a user equipment (UE) is in a stand-alone operating mode, wherein the source carrier is identified based at least in part on the determination that the UE is in the stand-alone operating mode.

11 . The method of claim 1 , wherein identifying the source carrier for the uplink grant comprises:
identifying a carrier in a licensed spectrum, wherein the uplink grant is cross-carrier controlled by the identified carrier.

12 . The method of claim 11 , further comprising:
receiving signaling indicative of a cross-carrier scheduling configuration, wherein the carrier in the licensed spectrum is identified based at least in part on the received signaling.

13 . The method of claim 1 , wherein a preamble transmitted using resources indicated by the uplink grant is based at least in part on the source carrier for the uplink grant.

14 . The method of claim 13 , wherein the source carrier comprises a carrier in the shared spectrum and the preamble comprises a wireless local area network (WLAN) preamble.

15 . An apparatus for wireless communications, comprising:
means for identifying a source carrier for an uplink grant; and means for determining a listen-before-talk (LBT) procedure for accessing a channel of a shared spectrum based at least in part on the source carrier for the uplink grant.

16 . The apparatus of claim 15 , wherein the means for determining the LBT procedure comprises:
means for determining a CCA period based at least in part on the source carrier for the uplink grant.

17 . The apparatus of claim 16 , wherein the CCA period comprises a first duration if the source carrier is in a shared spectrum and the CCA period comprises a second duration if the source carrier is in a licensed spectrum, wherein the second duration is greater than the first duration.

18 . The apparatus of claim 15 , wherein the means for determining the LBT procedure comprises:
means for determining a CCA procedure based at least in part on the source carrier for the uplink grant.

19 . The apparatus of claim 18 , wherein the means for determining the CCA procedure are operable to determine a CCA procedure without a backoff procedure.

20 . The apparatus of claim 18 , wherein the means for determining the CCA procedure are operable to determine a linear random or an exponential backoff procedure.

21 . The apparatus of claim 20 , wherein the means for determining the LBT procedure further comprises:
means for determining an LBT priority class for the exponential backoff procedure.

22 . The apparatus of claim 20 , further comprising:
means for selecting a first range parameter for the backoff procedure if the source carrier is in a shared spectrum; and means for selecting a second range parameter for the backoff procedure if the source carrier is in a licensed spectrum, wherein the second range parameter is greater than the first range parameter, wherein the first range parameter and the second range parameter are different from a range parameter associated with a base station from which the uplink grant is received.

23 . The apparatus of claim 15 , wherein the means for identifying the source carrier for the uplink grant comprises:
means for identifying a carrier in the shared spectrum.

24 . The apparatus of claim 23 , further comprising:
means for determining that a user equipment (UE) is in a stand-alone operating mode, wherein the means for identifying the source carrier is operable to determine that the UE is in the stand-alone operating mode.

25 . The apparatus of claim 15 , wherein means for identifying the source carrier for the uplink grant comprises:
means for identifying a carrier in a licensed spectrum, wherein the uplink grant is cross-carrier controlled by the identified carrier.

26 . The apparatus of claim 25 , further comprising:
means for receiving signaling indicative of a cross-carrier scheduling configuration, wherein the means for identifying the source carrier is operable to identify the licensed spectrum based at least in part on the received signaling.

27 . The apparatus of claim 15 , wherein a preamble transmitted using resources indicated by the uplink grant is based at least in part on the source carrier for the uplink grant.

28 . The apparatus of claim 27 , wherein the source carrier comprises a carrier in the shared spectrum and the preamble comprises a wireless local area network (WLAN) preamble.

29 . An apparatus for wireless communications, comprising:
a processor; and memory coupled to the processor, wherein the processor is configured to:
identify a source carrier for an uplink grant; and
determine a listen-before-talk (LBT) procedure for accessing a channel of a shared spectrum based at least in part on the source carrier for the uplink grant.

30 . The apparatus of claim 29 , wherein the processor is configured to:
determine a CCA period based at least in part on the source carrier for the uplink grant.

31 . The apparatus of claim 30 , wherein the CCA period comprises a first duration if the source carrier is in a shared spectrum and the CCA period comprises a second duration if the source carrier is in a licensed spectrum, wherein the second dur

Assignees

• Qualcomm Inc

Inventors

• Luo Tao
• Malladi Durga Prasad

Classifications

• H04W72/23

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

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title

• H04W72/1268 Primary

  of uplink data flows · CPC title

• H04W72/14

  Electricity · mapped topic

• H04W74/0808 Primary

  using carrier sensing, e.g. carrier sense multiple access [CSMA] · CPC title