Method for dynamic csi feedback

Patent metadata

Field	Value
Publication number	US-2016149679-A1
Application number	US-201514440960-A
Country	US
Kind code	A1
Filing date	Mar 11, 2015
Priority date	Oct 10, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

Systems and methods for providing Channel State Information (CSI) feedback in a cellular communications network are disclosed. In some embodiments, a base station of a cellular communications network disables inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device and receives one or more CSI reports from the wireless device that are generated by the wireless device with inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes disabled in response to the base station disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device. In this manner, CSI feedback is improved particularly in embodiments in which the base station transmits a beamformed CSI-RS resource(s) and reuses the same CSI-RS resource(s) for different beams over time.

First claim

1 . A method of operation of a base station of a cellular communications network to control Channel State Information Reference Symbol, CSI-RS, based channel estimation at a wireless device, comprising:
disabling, at a wireless device, inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes; and receiving one or more Channel State Information, CSI, reports from the wireless device that are generated by the wireless device with disabled inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes.

2 . The method of claim 1 wherein the base station transmits a beamformed CSI-RS resource, the beamformed CSI-RS resource corresponding to a beam direction, and reuses the same CSI-RS resource for different beam directions over time.

3 . The method of claim 1 wherein the wireless device utilizes two or more CSI processes for CSI reporting, and disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes comprises disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes on a per CSI process basis.

4 . The method of claim 1 wherein the wireless device utilizes two or more CSI processes for CSI reporting, and disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes comprises disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes for all of the two or more CSI processes.

5 . The method of claim 1 wherein disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes comprises disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes via Radio Resource Control, RRC, signaling.

6 . The method of claim 5 wherein disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes via RRC signaling comprises:
sending, in an RRC information element that configures a CSI process of the wireless device, an indication that inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes is not allowed for the CSI process of the wireless device.

7 . The method of claim 1 further comprising disabling, at the wireless device, combining of CSI Interference Measurement, CSI-IM, estimates across subframes.

8 . The method of claim 1 wherein disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes comprises signaling, to the wireless device an indication that inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes is not allowed.

9 . The method of claim 1 further comprising configuring the wireless device with a set of CSI-RS resources.

10 . The method of claim 9 wherein receiving the one or more CSI reports from the wireless device comprises receiving CSI reports for a subset of the set of CSI-RS resources configured for the wireless device.

11 . The method of claim 9 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 Radio Resource Control, RRC, signaling.

12 . The method of claim 9 wherein configuring the wireless device with the set of CSI-RS resources comprises semi-statically configuring the wireless device with the set of CSI-RS resources.

13 . The method of claim 9 wherein the set of CSI-RS resources is specific to a CSI process of the wireless device.

14 . The method of claim 9 wherein the base station transmits beamformed CSI-RS, and the method further comprises dynamically changing beams used on the set of CSI-RS resources configured for the wireless device, each beam corresponding to a different beam direction.

15 . A base station of a cellular communications network enabled to control Channel State Information Reference Symbol, CSI-RS, based channel estimation at a wireless device comprising:
means for disabling, at a wireless device, inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes; and means for receiving a Channel State Information, CSI, report from the wireless device that is generated by the wireless device with inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes disabled in response to disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device.

16 . The base station of claim 15 wherein the base station transmits beamformed CSI-RS and reuses the same CSI-RS resources for different beams over time.

17 . The base station of claim 15 wherein the base station further comprises a means for disabling averaging of CSI Interference Measurement, CSI-IM, estimates across subframes for the wireless device.

18 . A base station of a cellular communications network enabled to control Channel State Information Reference Symbol, CSI-RS, based channel estimation at a wireless device 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:
disable, via the at least one transmitter, inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at a wireless device; and
receive, via the at least one receiver, a Channel State Information, CSI, report from the wireless device that is generated by the wireless device with inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes disabled in response to disabling inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes at the wireless device.

19 . (canceled)

20 . (canceled)

21 . A method of operation of a wireless device in a cellular communications network to provide Channel State Information, CSI, reporting, comprising:
receiving an indication from a base station of the cellular communications network to disable inter-subframe channel interpolation and/or filtering of Channel State Information Reference Symbol, CSI-RS, estimates across subframes; in response, performing one or more CSI-RS measurements with inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes disabled; and transmitting a CSI report to the base station determined from the one or more CSI-RS measurements.

22 . The method of claim 21 wherein the base station transmits a beamformed CSI-RS resource and reuses the same CSI-RS resource for different beams over time.

23 . The method of claim 21 wherein the wireless device utilizes two or more CSI processes for CSI reporting, and the indication received from the base station is an indication to disable inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes for a particular CSI process.

24 . The method of claim 21 wherein the wireless device utilizes two or more CSI processes for CSI reporting, and the indication received from the base station is an indication to disable inter-subframe channel interpolation and/or filtering of CSI-RS estimates across subframes for all of the two or more CSI processes.

25 . The method of claim 21 wherein receiving the indication comprises receiving the indication via Radio Resource Control, RRC, s

Assignees

• Ericsson Telefon Ab L M

Inventors

• Frenne Mattias
• Furuskog Johan
• Jöngren George
• Harrison Mark

Classifications

• H04L5/005 Primary

  of common pilots, i.e. pilots destined for multiple users or terminals · 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