Reference signal transmission in wireless communications with multiple receivers

• US 10,129,770 B2
• Filed: 03/08/2017
• Issued: 11/13/2018
• Est. Priority Date: 04/06/2016
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Yoo, Taesang, Vasudevan, Dinkar, Sun, Jing, Montojo, Juan
• Primary Examiner(s): Siddiqui, Kasif
• Application Number:
  US15/453,736
• Publication Number:
  US 20170295504A1
• Time in Patent Office: 615 Days
• CPC Class Codes: H04L 1/001 applied to control information
• 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: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Methods, systems, and devices for broadcast transmissions in wireless communication are described. A base station may transmit a control reference signal (CRS), a UE-specific reference signal (UERS), and broadcast data (e.g., broadcast physical downlink shared channel (PDSCH) data) in a broadcast downlink transmission. A UE may identify that the CRS and UERS are associated with the broadcast downlink data, and demodulate the broadcast downlink data in the broadcast downlink transmission based at least in part on the CRS and UERS. A UE may estimate a frequency offset based on a phase difference between the CRS and UERS, combine the CRS and UERS for use in a channel estimation, and demodulate the broadcast data based at least in part on the estimated frequency offset and channel estimation. The base station may provide signaling, such as dynamic or semi-static signaling, that indicates presence of both CRS and UERS.

Claims

1. A method for wireless communication, comprising:

receiving, at a user equipment (UE), a downlink (DL) grant for a broadcast DL transmission from a base station, the DL grant being associated with a control reference signal (CRS);

identifying a transmission type of broadcast data in the broadcast DL transmission;

receiving the broadcast data, wherein the broadcast data is broadcast to a plurality of UEs;

identifying that the CRS and a UE specific reference signal (UERS) are associated with the broadcast data based at least in part on the identified transmission type of the broadcast data; and

demodulating the broadcast data based at least in part on the CRS and the UERS.

2. The method of claim 1, wherein identifying that the CRS and UERS are associated with the broadcast data comprises:

identifying that the UERS is associated with the broadcast data;

identifying that the CRS is further associated with the broadcast data; and

the demodulating the broadcast data is further based at least in part on an assumption that a same precoding is used for transmission of the CRS and UERS.

3. The method of claim 1, wherein demodulating the broadcast data comprises:

estimating a frequency offset based at least in part on a phase difference between the CRS and UERS; and

demodulating the broadcast data based at least in part on the estimated frequency offset.

4. The method of claim 3, wherein demodulating the broadcast data further comprises:

combining the CRS and UERS for use in a channel estimation; and

demodulating the broadcast data based at least in part on the channel estimation.

5. The method of claim 1, wherein a one or more antenna port of the UERS is mapped to a corresponding one or more antenna port of the CRS.

6. The method of claim 1, wherein identifying that the CRS and UERS are associated with the broadcast data comprises:

receiving signaling that indicates that both CRS and UERS are present and associated with the broadcast data.

7. The method of claim 6, wherein the signaling is semi-static signaling that applies to certain types of broadcast data that are transmitted to the plurality of UEs.

8. The method of claim 7, wherein a type of broadcast data is provided in the DL grant associated with the broadcast data.

9. The method of claim 6, wherein the signaling is dynamic signaling that applies to the broadcast data.

10. The method of claim 9, wherein the dynamic signaling is provided in the DL grant associated with the broadcast data.

11. A method of wireless communication comprising:

identifying a plurality of receivers that are to receive a broadcast downlink (DL) transmission;

formatting a DL grant for the broadcast DL transmission, wherein the DL grant is associated with a control reference signal (CRS);

formatting broadcast data, the CRS, and a user equipment (UE) specific reference signal (UERS) in the broadcast DL transmission, wherein a transmission type of the broadcast data is associated with both the CRS and the UERS;

transmitting the DL grant to the plurality of receivers; and

transmitting the broadcast DL transmission to the plurality of receivers.

12. The method of claim 11, wherein formatting the CRS, the DL grant, the UERS, and broadcast data for transmission in the broadcast DL transmission comprises:

applying a same precoding to the CRS, and UERS.

13. The method of claim 11, wherein transmitting the broadcast DL transmission comprises:

transmitting the CRS using a first set of antenna ports; and

transmitting the UERS using a second set of antenna ports that are one-to-one mapped to the first set of antenna ports.

14. The method of claim 11, further comprising:

transmitting signaling indicating that both the CRS and the UERS are associated with the broadcast data.

15. The method of claim 14, wherein the signaling is semi-static signaling that applies to a plurality of broadcast data.

16. The method of claim 14, wherein the signaling is dynamic signaling that applies to one set of broadcast data.

17. 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;

receive, at a user equipment (UE), a downlink (DL) grant for a broadcast DL transmission from a base station, the DL grant being associated with a control reference signal (CRS);

identify a transmission type of broadcast data in the broadcast DL transmission;

receive the broadcast data, wherein the broadcast data is broadcast to a plurality of UEs;

identify that the CRS and a UE specific reference signal (UERS) are associated with the broadcast data based at least in part on the identified transmission type of the broadcast data; and

demodulate the broadcast data based at least in part on the CRS and the UERS.

18. The apparatus of claim 17, wherein the instructions are further operable to cause the processor to cause the apparatus to:

identify that the UERS is associated with the broadcast data;

identify that the CRS is further associated with the broadcast data; and

demodulate the broadcast data based at least in part on an assumption that a same precoding is used for transmission of the CRS and UERS.

19. The apparatus of claim 17, wherein the instructions are further operable to cause the processor to cause the apparatus to:

estimate a frequency offset based at least in part on a phase difference between the CRS and UERS; and

demodulate the broadcast data based at least in part on the estimated frequency offset.

20. The apparatus of claim 19, wherein the instructions are further operable to cause the processor to cause the apparatus to:

combine the CRS and UERS for use in a channel estimation; and

demodulate the broadcast data based at least in part on the channel estimation.

21. The apparatus of claim 17, wherein the instructions are further operable to cause the processor to cause the apparatus to:

receive signaling that indicates that both CRS and UERS are present and associated with the broadcast data.

22. The apparatus of claim 21, wherein the signaling is semi-static signaling that applies to certain types of broadcast data that are transmitted to the plurality of UEs, and a type of broadcast data is provided in the DL grant associated with the broadcast data.

23. The apparatus of claim 21, wherein the signaling is dynamic signaling that applies to the broadcast DL transmission.

24. 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 plurality of receivers that are to receive a broadcast downlink (DL) transmission;

format a DL grant for the broadcast DL transmission, wherein the DL grant is associated with a control reference signal (CRS);

format broadcast data, the CRS, and a user equipment (UE) specific reference signal (UERS) in the broadcast DL transmission, wherein a transmission type of the broadcast data is associated with both the CRS and the UERS;

transmit the DL grant to the plurality of receivers; and

transmit the broadcast DL transmission to the plurality of receivers.

25. The apparatus of claim 24, wherein the instructions are further operable to cause the processor to cause the apparatus to:

apply a same precoding to the CRS and UERS.

26. The apparatus of claim 24, wherein the instructions are further operable to cause the processor to cause the apparatus to:

transmit the CRS using a first set of antenna ports; and

transmit the UERS using a second set of antenna ports that are one-to-one mapped to the first set of antenna ports.

27. The apparatus of claim 24, wherein the instructions are further operable to cause the processor to cause the apparatus to:

transmit signaling indicating that both the CRS and the UERS are associated with the broadcast data.

28. The apparatus of claim 27, wherein the signaling is semi-static signaling that applies to a plurality of broadcast data.