DISCOVERY REFERENCE SIGNAL TRANSMISSION AND DECODING AND MEASUREMENT TECHNIQUES IN A WIRELESS COMMUNICATION SYSTEM

• US 20170311316A1
• Filed: 04/20/2017
• Published: 10/26/2017
• Est. Priority Date: 04/22/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chendamarai Kannan, Arumugam, Radulescu, Andrei Dragos, Patel, Chirag, Luo, Tao, Kadous, Tamer
• Granted Patent: US 10,349,404 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 68/00 User notification, e.g. alerting and paging, for incoming communication, change of service or the like
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/56 based on priority criteria

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may monitor for discovery reference signal (DRS) transmissions, physical downlink shared channel (PDSCH) transmissions, or combinations thereof within a DRS transmission window. The UE may attempt to decode DRS or PDSCH transmissions for a subframe based on detection of DRS transmissions, prioritization of DRS transmissions relative to PDSCH transmissions, locations of subframes within a radio frame, overlapping of the DRS transmission window with a paging opportunity, or any combination thereof. In some cases, one or more radio link monitoring (RLM) parameters may be adjusted based on decoding of PDSCH or DRS transmissions.

Claims

1. A method for wireless communications, comprising:

identifying a user equipment (UE) capability to monitor multiple scrambling hypotheses for transmissions received within a subframe;

identifying one or more subframes within a discovery reference signal (DRS) transmission window; and

attempting to decode a DRS transmission or a physical downlink shared channel (PDSCH) transmission in the one or more subframes based at least in part on the UE capability.

2. The method of claim 1, wherein attempting to decode the DRS transmission or PDSCH transmission comprises:

applying a first scrambling hypothesis to a first subframe of the one or more subframes;

attempting to decode the DRS transmission in the first subframe;

applying the first scrambling hypothesis to a second subframe of the one or more subframes subsequent to the first subframe based at least in part on unsuccessfully decoding the DRS transmission in the first subframe; and

applying a second scrambling hypothesis to the second subframe based at least in part on successfully decoding the DRS transmission in the first subframe.

3. The method of claim 1, further comprising:

determining that a high priority PDSCH transmission is to be monitored during at least a subset of subframes within the DRS transmission window; and

wherein attempting to decode the DRS transmission or PDSCH transmission comprises;

identifying a distinct scrambling hypothesis for each subframe within the subset of subframes to be monitored for the high priority PDSCH transmission; and

attempting to decode one or more subframes within the subset of subframes based at least in part on the distinct scrambling hypothesis associated with each of the one or more subframes within the subset.

4. The method of claim 3, wherein attempting to decode the DRS transmission or PDSCH transmission further comprises, for each subframe in the DRS transmission window:

determining, at each subframe in the DRS transmission window, that the DRS transmission was not previously successfully decoded in the DRS transmission window;

determining that the subframe is not to be monitored for a high priority PDSCH transmission; and

attempting to decode the DRS transmission using a same scrambling hypothesis as prior attempted decode of the DRS transmission in the DRS transmission window.

5. The method of claim 4, wherein the same scrambling hypothesis used for attempting to decode the DRS transmission corresponds to a scrambling hypothesis for subframe zero or subframe five of a radio frame.

6. The method of claim 1, further comprising:

determining that the DRS transmission could have been missed in a subset of subframes monitored for PDSCH transmission; and

adjusting a block error rate (BLER) weighting based at least in part on an assumption that the DRS transmission was missed.

7. The method of claim 1, further comprising:

determining that the DRS transmission could have been missed in a subset of subframes monitored for PDSCH transmission; and

adjusting a radio link monitoring (RLM) evaluation window based at least in part on an assumption that the DRS transmission was missed.

8. The method of claim 1, wherein attempting to decode the DRS transmission or PDSCH transmission comprises:

applying a first scrambling hypothesis to a first subset of subframes within the DRS transmission window until the DRS transmission is successfully detected;

applying a second scrambling hypothesis to each of one or more subframes of a second subset of subframes within the DRS transmission window to attempt to decode the PDSCH transmission, wherein the second subset is subsequent to the first subset of subframes; and

signaling to a base station that the first subset of subframes were not monitored for the PDSCH transmission.

9. The method of claim 1, wherein the DRS transmission window is a first DRS transmission window, and wherein attempting to decode the DRS transmission or the PDSCH transmission comprises attempting to decode the DRS transmission in subframes of the first DRS transmission window, and wherein the method further comprises:

identifying one or more subframes within a second DRS transmission window; and

attempting to decode the PDSCH transmission in the one or more subframes of the second DRS transmission window.

10. The method of claim 1, further comprising:

determining that a scheduled paging opportunity during which a paging message may be transmitted to the UE overlaps with the DRS transmission window, the paging opportunity comprising a set of subframes to be monitored for the paging message; and

shifting the set of subframes to be monitored for the paging message to be non-overlapping with the DRS transmission window.

11. The method of claim 10, wherein shifting the set of subframes to be monitored for the paging message to be non-overlapping with the DRS transmission window comprises:

shifting the set of subframes to start a determined number of subframes following the DRS transmission, the start of the DRS transmission window, or the start of the scheduled paging opportunity.

12. The method of claim 11, wherein the determined number of subframes is based at least in part on a UE specific identifier, a starting subframe number of the paging opportunity, or a combination thereof.

13. The method of claim 1, further comprising:

signaling the UE capability to a base station.

14. A method for wireless communication, comprising:

identifying a UE capability to monitor for a discovery reference signal (DRS) and a physical downlink shared channel (PDSCH) transmission within a same subframe; and

determining one or more parameters associated with at least one of a DRS transmission or PDSCH transmission based at least in part on the UE capability.

15. The method of claim 14, wherein the determining one or more parameters comprises:

modifying a radio link monitoring (RLM) threshold based at least in part on the UE capability.

16. The method of claim 14, wherein the determining one or more parameters comprises:

selecting a subframe for DRS transmission based at least in part on the UE capability.

17. The method of claim 16, wherein the selecting a subframe for DRS transmission comprises selecting a subframe having a same scrambling sequence as used for the DRS transmission.

18. The method of claim 16, wherein the selecting a subframe for DRS transmission comprises selecting a first allowed subframe within a DRS transmission window for DRS transmission.

19. The method of claim 16, wherein the determining one or more parameters further comprises:

selecting a DRS subframe within a DRS transmission window for DRS transmission that is subsequent to one or more other subframes within the DRS transmission window;

transmitting PDSCH transmissions in the one or more other subframes;

receiving a negative acknowledgment (NACK) for the PDSCH transmissions in the one or more other subframes; and

discounting the NACK in a link adaptation procedure based at least in part on the UE capability.

20. The method of claim 14, wherein the determining one or more parameters comprises:

determining that a PDSCH transmission is transmitted in a subframe during which the UE is monitoring for DRS transmissions; and

retransmitting the PDSCH transmission based at least in part on determining that the PDSCH transmission is transmitted in the subframe during which the UE is monitoring for DRS transmissions and the UE capability.

21. The method of claim 14, wherein the determining one or more parameters comprises:

selecting one or more subframes for a paging transmission that is outside of a DRS transmission window.

22. The method of claim 14, wherein the determining one or more parameters comprises:

determining that a paging opportunity overlaps with a DRS transmission window; and

selecting one or more subframes within the DRS transmission window for a paging transmission that have a same scrambling sequence as the DRS transmission.

23. The method of claim 14, wherein the determining one or more parameters comprises:

determining that a paging opportunity during which a paging message may be transmitted to the UE overlaps with a DRS transmission window, the paging opportunity comprising a set of subframes for transmission of the paging message; and

shifting the set of subframes for transmission of the paging message to be non-overlapping with the DRS transmission window.

24. The method of claim 23, wherein shifting the set of subframes to be monitored for the paging message to be non-overlapping with the DRS transmission window comprises:

shifting the set of subframes to start a determined number of subframes following the DRS transmission, the start of the DRS transmission window, or the start of the paging opportunity.

25. The method of claim 24, wherein the determined number of subframes is based at least in part on a UE specific identifier, a starting subframe number of the paging opportunity, or a combination thereof.

26. The method of claim 141, further comprising:

receiving signaling from the UE indicating the UE capability.

27. An apparatus for wireless communication, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to;

identify a user equipment (UE) capability to monitor multiple scrambling hypotheses for transmissions received within a subframe;

identify one or more subframes within a discovery reference signal (DRS) transmission window; and

attempt to decode a DRS transmission or a physical downlink shared channel (PDSCH) transmission in the one or more subframes based at least in part on the UE capability.

28. The apparatus of claim 27, wherein the instructions are executable by the processor to cause the apparatus to:

apply a first scrambling hypothesis to a first subframe of the one or more subframes;

attempt to decode the DRS transmission in the first subframe;

apply the first scrambling hypothesis to a second subframe of the one or more subframes subsequent to the first subframe based at least in part on unsuccessfully decoding the DRS transmission in the first subframe; and

apply a second scrambling hypothesis to the second subframe based at least in part on successfully decoding the DRS transmission in the first subframe.

29. An apparatus for wireless communication, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to;

identify a UE capability to monitor for a discovery reference signal (DRS) and a physical downlink shared channel (PDSCH) transmission within a same subframe; and

determine one or more parameters associated with at least one of a DRS transmission or PDSCH transmission based at least in part on the UE capability.

30. The apparatus of claim 29, wherein the instructions are executable by the processor to cause the apparatus to:

modify a radio link monitoring (RLM) threshold based at least in part on the UE capability.