Techniques for configuring reference signals in low latentcy wireless communications

• US 10,021,712 B2
• Filed: 10/14/2016
• Issued: 07/10/2018
• Est. Priority Date: 02/05/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Patel, Shimman Arvind, Chen, Wanshi
• Primary Examiner(s): Clawson, Stephen J
• Application Number:
  US15/294,453
• Publication Number:
  US 20170230992A1
• Time in Patent Office: 634 Days
• Field of Search: 370330
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04L 5/0087 when data requirements change
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/046 the resource being in the space domain, e.g. beams
• CPC Class Codes: H04W 72/1268 of uplink data flows
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Various aspects described herein relate to determining a configuration of reference signal (RS) resources in wireless communications. A scheduling grant of resources can be received from an access point, wherein the scheduling grant indicates one or more parameters related to transmission locations of one or more RSs. RS resource locations can be determined for the one or more RSs based at least in part on the one or more parameters. The one or more RSs can be received over the RS resource locations allowing for decimation of the RSs in time and/or frequency.

Claims

1. A method for determining a configuration of reference signal (RS) resources in wireless communications, comprising:

receiving, from an access point, a scheduling grant of resources, wherein the scheduling grant indicates one or more parameters related to transmission locations of one or more RSs, wherein the scheduling grant indicates a process number corresponding to channel state information (CSI)-RS transmission;

determining RS resource locations for the one or more RSs based at least in part on the one or more parameters, wherein determining the RS resource locations includes determining at least a transmission time interval (TTI) during which the CSI-RS is transmitted by the access point based at least in part on the process number; and

receiving the one or more RSs over the RS resource locations, wherein receiving the one or more RSs includes receiving, from the access point, the CSI-RS during the TTI.

2. The method of claim 1, further comprising:

generating one or more measurements of the CSI-RS;

receiving an uplink scheduling grant for reporting CSI feedback for the CSI; and

reporting the one or more measurements as the CSI feedback to the access point in a subsequent TTI based on the uplink scheduling grant.

3. The method of claim 2, wherein reporting the one or more measurements includes multiplexing the one or more measurements with data for transmitting over a channel corresponding to the uplink scheduling grant.

4. The method of claim 2, wherein reporting the one or more measurements includes transmitting the one or more measurements over a segment of a channel corresponding to the uplink scheduling grant.

5. The method of claim 4, wherein the uplink scheduling grant indicates an index of the segment.

6. The method of claim 1, further comprising determining a number of antenna ports corresponding to the process number, wherein the CSI-RS are received over the number of antenna ports.

7. The method of claim 6, further comprising determining one or more RS tones in frequency that correspond to the number of antenna ports, wherein the CSI-RS are received over the one or more RS tones.

8. The method of claim 7, wherein determining the one or more RS tones is based at least in part on whether a user equipment (UE)-RS is transmitted in the TTI.

9. The method of claim 1, wherein the scheduling grant further indicates whether a user equipment (UE)-RS is to be received in a transmission time interval (TTI), wherein determining the RS resource locations includes determining at least a transmission time interval (TTI) for receiving the UE-RS, and wherein receiving the one or more RS s includes receiving, from the access point, the UE-RS during the TTI.

10. The method of claim 9, wherein determining at least the TTI is based at least in part on the one or more parameters specified in the scheduling grant.

11. The method of claim 9, further comprising receiving, from the access point, a channel state information (CSI)-RS in the TTI.

12. The method of claim 1, further comprising reporting cell-specific reference signal (CRS) measurements to the access point, wherein the one or more parameters indicate RS frequency tones for the one or more RSs that are based on the CRS measurements.

13. The method of claim 1, wherein the scheduling grant further indicates whether channel state information (CSI)-interference management (IM) is enabled for a transmission time interval (TTI), and further comprising performing interference measurements or rate matching based on configured CSI-IM resource locations.

14. The method of claim 13, further comprising determining the configured CSI-IM resource locations based on receiving an indication of the configured CSI-IM resource locations within the TTI in a radio resource control (RRC) configuration.

15. The method of claim 1, further comprising determining a level of interference from one or more access points over multiple transmission time intervals (TTI) based at least in part on demodulating and decoding control signals within the multiple TTIs, obtaining channel estimates per each of the multiple TTIs based on remodulating the control signals to eliminate control data, and subtracting the channel estimates.

16. A method for specifying a configuration of resources for transmitting reference signals (RS) in wireless communications, comprising:

generating a scheduling grant of resources for communicating with a user equipment (UE), wherein the scheduling grant indicates one or more parameters related to transmitting one or more RSs, and wherein the scheduling grant indicates a process number corresponding to channel state information (CSI)-RS transmission;

transmitting the scheduling grant to the UE; and

transmitting the one or more RSs over RS resources based at least in part on the one or more parameters, wherein transmitting the one or more RSs includes transmitting the CSI-RS during a transmission time interval (TTI) corresponding to the process number.

17. The method of claim 16, further comprising transmitting an uplink scheduling grant to the UE for transmitting CSI feedback.

18. The method of claim 17, further comprising receiving, from the UE in a subsequent TTI based on the uplink scheduling grant, CSI feedback corresponding to the CSI-RS.

19. The method of claim 18, wherein receiving the CSI feedback includes receiving the CSI feedback multiplexed with data over a channel corresponding to the uplink scheduling grant.

20. The method of claim 18, wherein the uplink scheduling grant indicates an index of a segment of the channel, where other segments are assigned to other UEs, and wherein receiving the CSI feedback includes receiving the CSI feedback in the segment of the channel.

21. The method of claim 16, wherein transmitting the CSI-RS includes transmitting the CSI-RS over a number of antenna ports corresponding to the process number.

22. The method of claim 21, further comprising signaling a plurality of process numbers and associated parameters to the UE using radio resource control (RRC) signaling), wherein transmitting the CSI-RS is based on the associated parameters for the process number.

23. The method of claim 21, wherein transmitting the CSI-RS includes transmitting the CSI-RS over a channel in frequency that corresponds to the number of antenna ports.

24. The method of claim 16, further comprising transmitting, to the UE, a user equipment (UE)-RS in the TTI.

25. The method of claim 16, further comprising:

receiving an estimate of a channel coherence bandwidth from the UE corresponding to a cell-specific reference signal (CRS) transmission; and

determining a number of frequency tones for the one or more RSs based at least in part on the estimate of the channel coherence bandwidth, wherein transmitting the one or more RS s is based on the number of frequency tones.

26. The method of claim 16, wherein the scheduling grant indicates whether channel state information (CSI)-interference management (IM) is enabled for a transmission time interval (TTI).

27. An apparatus for wireless communications, comprising:

a transceiver for communicating one or more wireless signals via one or more antennas;

a memory configured to store instructions; and

one or more processors communicatively coupled with the transceiver and the memory, wherein the transceiver is configured to;

receive, from an access point, a scheduling grant of resources, wherein the scheduling grant indicates one or more parameters related to transmission locations of one or more reference signals (RS), wherein the scheduling grant indicates a process number corresponding to channel state information (CSI)-RS transmission;

wherein the one or more processors are configured to;

determine RS resource locations for the one or more RSs based at least in part on the one or more parameters, wherein the one or more processors are further configured to determine at least a transmission time interval (TTI) during which the CSI-RS is transmitted by the access point based at least in part on the process number; and

wherein the transceiver is further configured to;

receive the one or more RSs over the RS resource locations, wherein the transceiver is further configured to receive, from the access point, the CSI-RS during the TTI.

28. An apparatus for wireless communications, comprising:

a transceiver for communicating one or more wireless signals via one or more antennas;

a memory configured to store instructions; and

one or more processors communicatively coupled with the transceiver and the memory, wherein the one or more processors are configured to;

generate a scheduling grant of resources for communicating with a user equipment (UE), wherein the scheduling grant indicates one or more parameters related to communicating one or more reference signals (RS), and wherein the scheduling grant indicates a process number corresponding to channel state information (CSI)-RS transmission; and

wherein the transceiver is configured to;

transmit the scheduling grant to the UE; and

transmit the one or more RSs over RS resources based at least in part on the one or more parameters, wherein the CSI-RS are transmitted during a transmission time interval (TTI) corresponding to the process number.