Reference signal for a coordinated multi-point network implementation

Patent metadata

Field	Value
Publication number	US-9270347-B2
Application number	US-201113578550-A
Country	US
Kind code	B2
Filing date	Feb 14, 2011
Priority date	Feb 12, 2010
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

A system and method of receiving a channel state information reference signal (CSI-RS) is presented. At a user equipment, a first CSI-RS transmitted from a base station is received. In some implementations, the first CSI-RS is transmitted at a first periodicity using a first set of antenna ports. At the user equipment, a second CSI-RS transmitted from the base station is received. In some implementations, the second CSI-RS is transmitted at a second periodicity using a second set of antenna ports. At least one of the first CSI-RS and the second CSI-RS is used to perform channel measurement.

First claim

The invention claimed is:

1. A method of operating a user equipment (UE) in a wireless communications network, the method comprising:
receiving, by the UE, a first channel state information reference signal (CSI-RS) transmitted from a base station, the first CSI-RS being transmitted at a first periodicity using a first set of antenna ports;
receiving, by the UE, a second CSI-RS transmitted from the base station, the second CSI-RS being transmitted at a second periodicity using a second set of antenna ports, wherein the second set of antenna ports comprises fewer ports than the first set of antenna ports, and the second periodicity is greater than the first periodicity;
determining the UE moves relative to the base station at a speed greater than a threshold; and
in response to the determining, using, by UE, the second CSI-RS to perform channel measurement.

2. The method of claim 1 , wherein the first CSI-RS is transmitted in a first resource of a first radio frame.

3. The method of claim 2 , wherein the second CSI-RS is transmitted in a second resource of a second radio frame.

4. The method of claim 3 , wherein the first radio frame and the second radio frame are the same radio frame.

5. The method of claim 3 , wherein the first resource and the second resource are transmitted in the same subframe of a radio frame.

6. The method of claim 1 , wherein the second set of antenna ports is a subset of the first set of antenna ports.

7. The method of claim 1 , including receiving an instruction from the base station identifying the second CSI-RS to use for channel measurement.

8. The method of claim 7 , including transmitting a channel measurement report to the base station, the measurement report indicating the channel measurement is based on the second CSI-RS for channel.

9. The method of claim 1 , including:
receiving an antenna mapping from the base station, the antenna mapping identifying the second set of antenna ports.

10. The method of claim 1 , wherein the second set of antenna ports includes a virtual antenna comprising a combination of two or more antenna ports from the first set of antenna ports.

11. The method of claim 1 , including:
receiving an identification from the base station of a third CSI-RS of a neighbor cell, wherein the third CSI-RS is received in one or more resource elements; and
muting at least one of the one or more resource elements corresponding to the third CSI-RS.

12. A method of operating a base station in a wireless communications network, the method comprising:
transmitting, by a base station, a first channel state information reference signal (CSI-RS) to a user equipment, the first CSI-RS being transmitted at a first periodicity using a first set of antenna ports;
transmitting, from by the base station, a second CSI-RS to the user equipment, the second CSI-RS being transmitted at a second periodicity using a second set of antenna ports, wherein the second set of antenna ports comprises fewer ports than the first set of antenna ports, and the second periodicity is greater than the first periodicity; and
receiving, by the base station, a channel measurement report from the user equipment, the channel measurement report being based upon the second CSI-RS used when the UE moves relative to the base station at a speed greater than a threshold.

13. The method of claim 12 , wherein the first CSI-RS is transmitted in a first resource of a first radio frame.

14. The method of claim 13 , wherein the second CSI-RS is transmitted within a second resource of a second radio frame.

15. The method of claim 14 , wherein the first radio frame and the second radio frame are the same radio frame.

16. The method of claim 14 , wherein the first resource and the second resource are in the same subframe of a radio frame.

17. The method of claim 12 , wherein the second set of antenna ports is a subset of the first set of antenna ports.

18. The method of claim 12 , including transmitting an instruction to the user equipment identifying the second CSI-RS to use for channel measurement.

19. The method of claim 18 , including using the received channel measurement report to determine that the measurement report is based on the second CSI-RS to use for channel measurement.

20. The method of claim 12 , including:
transmitting an antenna mapping to the user equipment, the antenna mapping identifying the second set of antenna ports.

21. The method of claim 12 , wherein the second set of antenna ports includes a virtual antenna comprising a combination of two or more antenna ports from the first set of antenna ports.

22. The method of claim 12 , wherein the second set of antenna ports is a subset of the first set of antenna ports.

23. The method of claim 12 , including, when a load on the base station exceeds a predetermined threshold, decreasing a frequency of the second periodicity.

24. The method of claim 12 , including, when a load on the base station falls below a predetermined threshold, increasing a frequency of the second periodicity.

25. A user equipment, comprising:
a processor configured to communicate with a memory, the memory storing instructions, which when executed by the processor, cause the processor to perform the steps of:
receiving a first channel state information reference signal (CSI-RS) transmitted from a base station, the first CSI-RS being transmitted at a first periodicity using a first set of antenna ports;
receiving a second CSI-RS transmitted from the base station, the second CSI-RS being transmitted at a second periodicity using a second set of antenna ports, wherein the second set of antenna ports comprises fewer ports than the first set of antenna ports, and the second periodicity is greater than the first periodicity;
determining the UE moves relative to the base station at a speed greater than a threshold; and in response to the determining, using, by the user equipment, the second CSI-RS to perform channel measurement.

26. The user equipment of claim 25 , wherein the first CSI-RS is transmitted in a first resource of a first radio frame.

27. The user equipment of claim 26 , wherein the second CSI-RS is transmitted in a second resource of a second radio frame.

28. The user equipment of claim 27 , wherein the first radio frame and the second radio frame are the same radio frame.

29. The user equipment of claim 27 , wherein the first resource and the second resource are transmitted in the same subframe of a radio frame.

30. A base station, comprising:
a processor configured to communicate with a memory, the memory storing instructions, which when executed by the processor, cause the processor to perform the steps of:
transmitting a first CSI-RS to a user equipment, the first CSI-RS being transmitted at a first periodicity using a first set of antenna ports;
transmitting a second CSI-RS to the user equipment, the second CSI-RS being transmitted at a second periodicity using a second set of antenna ports, wherein the second set of antenna ports comprises fewer ports than the first set of antenna ports, and the second periodicity is greater than the first periodicity; and
receiving a channel measurement report from the user equipment, the channel measurement report being based upon the second CSI-RS used when the UE moves relative to the base station at a speed greater than

Assignees

• Fong Mo-Han
• Yu Dongsheng
• Xu Hua
• Novak Robert
• Guo Shiguang
• Cai Zhijun
• Heo Youn Hyoung
• Blackberry Ltd

Inventors

• Fong Mo-Han
• Yu Dongsheng
• Xu Hua
• Novak Robert
• Guo Shiguang
• Cai Zhijun
• Heo Youn Hyoung

Classifications

• H04L25/0204

  of multiple channels · CPC title

• H04L5/0048

  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

• H04L5/0073

  Allocation arrangements that take into account other cell interferences · CPC title

• H04L5/0023 Primary

  Time-frequency-space · CPC title

• H04W24/10

  Scheduling measurement reports {; Arrangements for measurement reports} · CPC title