Methods and apparatus for coordinated multipoint (CoMP) communications

Patent metadata

Field	Value
Publication number	US-9686772-B2
Application number	US-201313951250-A
Country	US
Kind code	B2
Filing date	Jul 25, 2013
Priority date	Aug 1, 2012
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

Certain aspects of the present disclosure relate to methods and apparatus for Coordinated Multipoint (CoMP) communications. Certain aspects relate to methods and apparatus for determining resource mapping and/or rate matching for CoMP operations.

First claim

What is claimed is:

1. A method for wireless communications by a user equipment (UE), comprising:
receiving signaling indicating different reference signal (RS) configurations for a set of base stations participating in Coordinated Multipoint (CoMP) operations to the user equipment (UE), each configuration identifying resources for use by one or more of the base stations in transmitting RSs;
receiving a downlink transmission in a subframe;
determining how to perform rate matching for the downlink transmission based on one or more of the indicated RS configurations;
determining quasi-co-location of one or more resources in the subframe based on the one or more of the indicated RS configurations; and
performing rate matching based on the determination of how to perform rate matching, wherein:
different base stations in the set support different uplink/downlink (UL/DL) time division duplexed (TDD) subframe configurations; and
the number of base stations participating in CoMP operations for any given subframe is dependent on the UL/DL TDD subframe configurations.

2. The method of claim 1 , wherein the signaling indicates a number of one or more antenna ports used for transmitting RS.

3. The method of claim 2 , wherein the signaling only indicates a number of antenna ports for a serving base station.

4. The method of claim 3 , wherein the actual number of antenna ports used by at least one of the base stations is different than the number of antenna ports for the serving base station.

5. The method of claim 1 , wherein the set of base stations are synchronized with a same subframe index and, within a period, a first subset of subframes are of a same subframe type.

6. The method of claim 5 , further comprising:
receiving signaling indicating a subframe type of a subframe that is not in the first subset and in which the downlink transmission is received; and
performing the rate matching based on a RS configuration selected based on the indicated subframe type.

7. The method of claim 6 , wherein the first set of subframes comprise subframes of a type other than Multicast-Broadcast Single Frequency Network (MBSFN) subframes.

8. The method of claim 1 , wherein the signaling comprises an indication of one or more frequency shift values.

9. The method of claim 8 , wherein the number of possible frequency shift values is dependent on a corresponding number of antenna ports.

10. The method of claim 1 , wherein at least one of the base stations transmit RS in a new carrier type in a limited number of subframes.

11. The method of claim 10 , further comprising receiving an indication of whether or not a base station transmits using a new carrier type and rate matching is performed in a manner dependent, at least in part, on the indication.

12. The method of claim 1 , wherein the signaling is conveyed via one or more physical cell identities (PCIs) and the method further comprises deriving the RS configurations based on the PCIs.

13. The method of claim 1 , wherein at least some of the base stations in the set have different special subframe configurations.

14. The method of claim 13 , wherein receiving signaling comprises receiving an indication of one or more special subframe configurations.

15. The method of claim 13 , wherein joint transmissions are not allowed from base stations with different special subframe configurations.

16. The method of claim 13 , wherein joint transmissions are allowed from base stations with different special subframe configurations using a common resource set.

17. The method of claim 13 , wherein joint transmissions are allowed only from base stations with special subframe configurations with same Downlink Pilot Time Slot (DwPTS) lengths.

18. The method of claim 1 , wherein only base stations that have a same subframe uplink or downlink type in a given subframe participate in CoMP operations in that subframe.

19. The method of claim 1 , further comprising performing channel estimation filtering only among subframes in which a same number of base stations participate in CoMP operations.

20. The method of claim 1 , wherein rate matching is performed in a manner dependent, at least in part, on a CoMP scheme.

21. The method of claim 20 , wherein for a joint transmission (JT) CoMP scheme, rate matching is performed based on a combination of RS configurations for base stations involved in the joint transmission.

22. The method of claim 20 , wherein for non-JT CoMP schemes, rate matching is performed based on individual RS configurations.

23. The method of claim 1 , wherein the signaling comprises an indication of a number of RS configurations.

24. The method of claim 23 , wherein, in a given subframe, the rate matching is performed based on a single one of the RS configurations.

25. The method of claim 23 , wherein, in a given subframe, the rate matching is performed based on a combination of RS configurations.

26. The method of claim 1 , wherein:
a first RS configuration is defined for subframes where all base stations have DL subframes;
a second RS configuration is defined for subframes where some base stations have DL subframes and some base stations have UL subframes; and
the UE performs rate matching by employing the first or second RS configuration based on a current combination of DL and UL subframes for the subframe in which the downlink transmission is received.

27. The method of claim 1 , wherein:
a first portion of the downlink transmission is received from a first base station;
a second portion of the downlink transmission is received from a second base station;
rate matching for the first portion of the downlink transmission is performed based on an RS configuration for the first base station; and
rate matching for the second portion of the downlink transmission is performed based on an RS configuration for the second base station.

28. The method of claim 1 , wherein rate matching is performed in a manner dependent on whether or not the UE is interference cancelation (IC) capable.

29. The method of claim 28 , wherein:
rate matching is performed based on a single base station RS configuration if the UE is IC capable; and
rate matching is performed based on a combination of base station RS configurations if the UE is not IC capable.

30. The method of claim 28 , wherein rate matching is performed in a manner also dependent on whether or not IC is enabled for the UE.

31. The method of claim 1 , wherein rate matching is performed in a manner dependent on one or more features of a channel type of the downlink transmission.

32. The method of claim 31 , wherein a first RS configuration corresponding to a serving base station is used for rate matching if the downlink transmission comprises a physical downlink control channel (PDCCH).

33. The method of claim 32 , wherein a second RS configuration is used for rate matching if the downlink transmission comprises an enhanced physical downlink control channel (ePDCCH) transmitted using resources conventionally used for a physical downlink shared channel (PDSCH).

34. The method of claim 32 , wherein different RS configurations may be used for rate matching depending on whether the downlink transmission is unicast or non-unicast.

35. The m

Assignees

• Qualcomm Inc

Inventors

• Chen Wanshi
• Xu Hao
• Gaal Peter
• Luo Tao
• Geirhofer Stefan
• Damnjanovic Aleksandar

Classifications

• H04W72/20 Primary

  Control channels or signalling for resource management · CPC title

• H04L5/0035

  Resource allocation in a cooperative multipoint environment · CPC title

• H04L5/0007

  the frequencies being orthogonal, e.g. OFDM(A) or DMT · CPC title

• H04L5/0091

  Signalling for the administration of the divided path, e.g. signalling of configuration information · CPC title

• H04L5/0048 Primary

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title