METHOD FOR CSI FEEDBACK

• US 20160105817A1
• Filed: 03/11/2015
• Published: 04/14/2016
• Est. Priority Date: 10/10/2014
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Frenne, Mattias, Furuskog, Johan, Harrison, Mark, Jongren, George
• Application Number:
  US14/441,252
• Publication Number:
  US 20160105817A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Embodiments of systems and methods for flexible Channel State Information (CSI) feedback in a cellular communications network are disclosed. In some embodiments, a base station configures a wireless device with a set of CSI-RS resources, dynamically configures a CSI-RS resource from the set of CSI-RS resources for measurement, and receives a CSI report from the wireless device determined from the CSI-RS resource dynamically configured for measurement. In this manner, the base station is enabled to dynamically configure and re-configure the CSI-RS resource(s) for measurement by the wireless device, which in turn provides flexible CSI feedback that is particularly well-suited for embodiments in which the base station transmits beamformed CSI-RS.

Claims

1. A method of operation of a base station of a cellular communications network to enable flexible Channel State Information, CSI, feedback, comprising:

configuring a wireless device with a set of Channel State Information Reference Symbol, CSI-RS, resources;

dynamically configuring a CSI-RS resource from the set of CSI-RS resources for measurement via one of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE.; and

receiving a CSI report from the wireless device determined from the CSI-RS resource dynamically configured for measurement.

2. The method of claim 1 wherein the base station transmits beamformed CSI-RS, each beamformed CSI-RS corresponding to a different beam direction.

3. The method of claim 2 wherein each CSI-RS resource in the set of CSI-RS resources is beamformed and each CSI-RS resource corresponds to a different beam direction.

4. The method of claim 1 wherein the wireless device uses two or more CSI processes for CSI reporting, and

configuring the wireless device with the set of CSI-RS resources comprises configuring the wireless device with the set of CSI-RS resources for a particular CSI process of the two or more CSI processes of the wireless device (14);

and

dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement comprises dynamically configuring the CSI-RS resource from the set of CSI-RS resources such that the CSI-RS resource is configured for measurement for the particular CSI process.

5. The method of claim 4 further comprising:

configuring the wireless device with a respective set of CSI-RS resources for each additional CSI process of the two or more CSI processes of the wireless device; and

for each additional CSI process of the wireless device, dynamically configuring a CSI-RS resource from the respective set of CSI-RS resources for measurement.

6. The method of claim 1 wherein the wireless device uses two or more CSI processes for CSI reporting, the set of CSI-RS resources is a common set of CSI-RS resources for the two or more CSI processes, and dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement comprises dynamically configuring the CSI-RS resource from the set of CSI-RS resources such that the CSI-RS resource is configured for measurement for the two or more CSI processes.

7. The method of claim 1 wherein configuring the wireless device with the set of CSI-RS resources comprises configuring the wireless device with the set of CSI-RS resources via higher layer signaling.

8. The method of claim 1 further comprising:

receiving one or more additional CSI reports from the wireless device determined from the CSI-RS resource dynamically configured for measurement, wherein the one or more additional CSI reports are transmitted at predetermined time instants.

9. The method of claim 1 further comprising:

receiving a subsequent CSI report from the wireless device determined from a default CSI-RS resource.

10. The method of claim 1 wherein dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement comprises dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement such that the dynamic configuration of the CSI-RS resource holds until a subsequent dynamic configuration of a new CSI-RS resource is provided to the wireless device.

11. The method of claim 1 further comprising:

dynamically configuring a CSI Interference Measurement, CSI-IM, resource from a set of CSI-IM resources configured for interference measurement.

12. The method of claim 1 wherein Physical Downlink Shared Channel, PDSCH, rate matching is provided over the set of CSI-RS resources.

13. The method of claim 8 further comprising receiving an indication from the wireless device confirming that the CSI-RS resource was used for the CSI report.

14. The method of claim 1 further comprising:

receiving an acknowledgement from the wireless device that indicates that the dynamic configuration of the CSI-RS resource was received by the wireless device; and

discarding any CSI reports received from the wireless device for a predefined amount of time after receiving the acknowledgement from the wireless device.

15. A base station of a cellular communications network, comprising:

means for configuring a wireless device with a set of Channel State Information Reference Symbol, CSI-RS, resources;

means for dynamically configuring a CSI-RS resource from the set of CSI-RS resources for measurement via one of a group consisting of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE.; and

means for receiving a CSI report from the wireless device determined from the CSI-RS resource dynamically configured for measurement.

16. The base station of claim 15 wherein the base station transmits beamformed CSI-RS, each beamformed CSI-RS corresponding to a different beam direction.

17. The base station of claim 16 wherein each CSI-RS resource in the set of CSI-RS resources is beamformed and each CSI-RS resource corresponds to a different beam direction.

18. The base station of claim 16 wherein the wireless device uses two or more CSI processes for CSI reporting, and

the means for configuring the wireless device with the set of CSI-RS resources is further operative to configure the wireless device with the set of CSI-RS resources for a particular CSI process of the two or more CSI processes of the wireless device;

and

the means for dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement is further operative to dynamically configure the CSI-RS resource from the set of CSI-RS resources such that the CSI-RS resource is configured for measurement for the particular CSI process.

19. The base station of claim 15 wherein the wireless device uses two or more CSI processes for CSI reporting, the set of CSI-RS resources is a common set of CSI-RS resources for the two or more CSI processes, and the means for dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement is further operative to dynamically configure the CSI-RS resource from the set of CSI-RS resources such that the CSI-RS resource is configured for measurement for the two or more CSI processes.

20. The base station of claim 15 further comprising:

means for receiving a subsequent CSI report from the wireless device determined from a default CSI-RS resource.

21. The base station of claim 15 wherein the means for dynamically configuring the CSI-RS resource from the set of CSI-RS resources for measurement is further operative to dynamically configure the CSI-RS resource from the set of CSI-RS resources for measurement such that the dynamic configuration of the CSI-RS resource holds until a subsequent dynamic configuration of a new CSI-RS resource is provided to the wireless device.

22. The base station of claim 15 further comprising:

means for dynamically configuring a different CSI-RS resource from the set of CSI-RS resources for interference measurement.

23. A base station of a cellular communications network, comprising:

at least one transmitter;

at least one receiver;

at least one processor; and

memory storing software instructions executable by the at least one processor whereby the base station is operative to;

configure, via the at least one transmitter, a wireless device with a set of Channel State Information Reference Symbol, CSI-RS, resources;

dynamically configure, via the at least one transmitter, a CSI-RS resource from the set of CSI-RS resources for measurement via one of a group consisting of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE; and

receive, via the at least one receiver, a CSI report from the wireless device determined from the CSI-RS resource dynamically configured for measurement.

24. A method of operation of a wireless device to provide flexible Channel State Information, CSI, feedback to a cellular communications network, comprising:

receiving a configuration of a set of Channel State Information Reference Symbol, CSI-RS, resources from a base station of the cellular communications network;

receiving a dynamic configuration a CSI-RS resource from the set of CSI-RS resources for measurement from the base station of the cellular communications network via one of a group consisting of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE;

performing one or more measurements on the CSI-RS resource dynamically configured for measurement; and

transmitting a CSI report to the base station determined from the one or more measurements on the CSI-RS resource dynamically configured for measurement.

25. The method of claim 24 wherein the base station transmits beamformed CSI-RS, each beamformed CSI-RS corresponding to a different beam direction.

26. The method of claim 25 wherein each CSI-RS resource in the set of CSI-RS resources is beamformed and each CSI-RS resource corresponds to a different beam direction.

27. The method of claim 24 wherein the wireless device uses two or more CSI processes for CSI reporting, and

receiving the configuration of the set of CSI-RS resources comprises receiving the configuration of the set of CSI-RS resources for a particular CSI process of the two or more CSI processes of the wireless device;

and

receiving the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources for measurement comprises receiving the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources for the particular CSI process.

28. The method of claim 27 further comprising:

receiving a configuration of a respective set of CSI-RS resources for each additional CSI process of the two or more CSI processes of the wireless device; and

for each additional CSI process of the wireless device, receiving a dynamic configuration of a CSI-RS resource from the respective set of CSI-RS resources for measurement.

29. The method of claim 24 wherein the wireless device uses two or more CSI processes for CSI reporting, the set of CSI-RS resources is a common set of CSI-RS resources for the two or more CSI processes, and receiving the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources for measurement comprises receiving the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources such that the CSI-RS resource is configured for measurement for the two or more CSI processes.

30. The method of claim 24 wherein receiving the configuration of the set of CSI-RS resources comprises receiving the configuration of the set of CSI-RS resources via higher layer signaling.

31. The method of claim 24 further comprising:

performing one or more additional measurements on the CSI-RS resource dynamically configured for measurement; and

transmitting one or more additional CSI reports from the wireless device determined from the one or more additional measurements on the CSI-RS resource dynamically configured for measurement, wherein the one or more additional CSI reports are transmitted at predetermined time instants.

32. The method of claim 24 further comprising:

performing one or more subsequent measurements on a default CSI-RS resource; and

transmitting a subsequent CSI report from the wireless device determined from the one or more subsequent measurements on the default CSI-RS resource.

33. The method of claim 24 wherein the dynamic configuration of the CSI-RS resource holds until a subsequent dynamic configuration of a new CSI-RS resource is provided to the wireless device.

34. The method of claim 24 further comprising:

receiving, from the base station, a dynamic configuration for a CSI-IM resource from a set of CSI-IM resources configured for interference measurement.

35. The method of claim 24 wherein Physical Downlink Shared Channel, PDSCH, rate matching over the set of CSI-RS resources is assumed by the wireless device.

36. The method of claim 31 further comprising transmitting an indication to the base station that confirms that the CSI-RS resource was used for the CSI report.

37. A wireless device enabled to provide flexible Channel State Information, CSI, feedback to a cellular communications network, comprising:

means for receiving a configuration of a set of Channel State Information Reference Symbol, CSI-RS, resources from a base station of the cellular communications network means for receiving a dynamic configuration a CSI-RS resource from the set of CSI-RS resources for measurement from the base station of the cellular communications network via one of a group consisting of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE;

means for performing one or more measurements on the CSI-RS resource dynamically configured for measurement; and

means for transmitting a CSI report to the base station determined from the one or more measurements on the CSI-RS resource dynamically configured for measurement.

38. The wireless device of claim 37 wherein the base station transmits beamformed CSI-RS, each beamformed CSI-RS corresponding to a different beam direction.

39. The wireless device of claim 38 wherein each CSI-RS resource in the set of CSI-RS resources is beamformed and each CSI-RS resource corresponds to a different beam direction.

40. The wireless device of claim 38 wherein the wireless device uses two or more CSI processes for CSI reporting, and

the configuration of the set of CSI-RS resources is for a particular CSI process of the two or more CSI processes of the wireless device;

and

the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources for measurement is for the particular CSI process.

41. The wireless device of claim 37 wherein the wireless device uses two or more CSI processes for CSI reporting, the set of CSI-RS resources is a common set of CSI-RS resources for the two or more CSI processes, and the dynamic configuration of the CSI-RS resource from the set of CSI-RS resources for measurement is for the two or more CSI processes.

42. The wireless device of claim 37 wherein the wireless device further comprises:

means for performing one or more subsequent measurements on a default CSI-RS resource; and

means for transmitting a subsequent CSI report from the wireless device determined from the one or more subsequent measurements on the default CSI-RS resource.

43. The wireless device of claim 37 wherein the dynamic configuration of the CSI-RS resource holds until a subsequent dynamic configuration of a new CSI-RS resource is provided to the wireless device.

44. The wireless device of claim 37 wherein the wireless device is further operative to:

receive, from the base station, a dynamic configuration for a CSI-IM resource from a set of CSI-RS resources configured for interference measurement.

45. The wireless device of claim 37 wherein Physical Downlink Shared Channel, PDSCH, rate matching over the set of CSI-RS resources is assumed by the wireless device.

46. The wireless device of claim 41 wherein the wireless device is further operative to transmit an indication to the base station that confirms that the CSI-RS resource was used for the CSI report.

47. A wireless device enabled to provide flexible Channel State Information, CSI, feedback to a cellular communications network, comprising:

at least one transmitter;

at least one receiver;

at least one processor; and

memory storing software instructions executable by the at least one processor whereby the wireless device is operative to;

receive a configuration of a set of Channel State Information Reference Symbol, CSI-RS, resources from a base station (12) of the cellular communications network;

receive a dynamic configuration a CSI-RS resource from the set of CSI-RS resources for measurement from the base station of the cellular communications network via one of a group consisting of;

an uplink scheduling grant;

a dedicated downlink control channel message;

a downlink assignment;

a Downlink Control Information, DCI, message; and

a Medium Access Control, MAC, Control Element, CE;

perform one or more measurements on the CSI-RS resource dynamically configured for measurement; and

transmit a CSI report to the base station based on the one or more measurements on the CSI-RS resource dynamically configured for measurement.