Enhanced CSI feedback for FD-MIMO

Patent metadata

Field	Value
Publication number	US-10826577-B2
Application number	US-201515531131-A
Country	US
Kind code	B2
Filing date	Jan 19, 2015
Priority date	Jan 19, 2015
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

Enhanced channel state information (CSI) feedback is disclosed for full dimensional multiple input, multiple output (FD-MIMO) operations. In one aspect, a single CSI process is defined that is configured with an azimuth and elevation CSI-reference signal (RS) ports. A user equipment (UE) will send a precoding matrix indictor (PMI) report including a precoding matrix indicator (PMI) for the azimuth ports and a PMI for the elevation ports. One of the PMIs is assigned a low rank. The base station will use the two PMIs to create a whole channel precoding matrix. In another aspect, a single CSI process is configured having a plurality of CSI-RS resources. The UE generates channel measurement information for each of the CSI-RS resources, but only sets a CSI report to the base station of a subset of the total number of resources.

First claim

What is claimed is:

1. A method of wireless communication, comprising:
receiving, at a user equipment (UE), a feedback configuration signal that configures a plurality of channel state information reference signal (CSI-RS) resources in a single channel state information (CSI) process;
generating, by the UE, channel measurement information for at least a portion of the plurality of CSI-RS resources; and
transmitting, by the UE, a CSI report including the channel measurement information for a subset of CSI-RS resources fewer than all of the plurality of CSI-RS resources, the subset including more than one CSI-RS resource, wherein the channel measurement information includes an indication of an index for each of the more than one CSI-RS resource of the subset for which the channel measurement information is transmitted.

2. The method of claim 1 , further including:
determining, by the UE, a spectrum efficiency associated with each of the plurality of CSI-RS resources; and
selecting, by the UE, each of the more than one CSI-RS resource of the subset for which the channel measurement information is transmitted based, at least in part, on the determined spectral efficiency.

3. The method of claim 1 , further including:
receiving, by the UE, an aperiodic CSI request, wherein a triggering command of the aperiodic CSI request includes a resource indicator identifying one or more of the plurality of CSI-RS resources for the subset.

4. The method of claim 1 , further including:
determining, by the UE, a reporting subframe in which aperiodic CSI measurements are to be reported; and
determining, by the UE, whether there are valid CSI-RS resources of the subset within a pre-configured time domain threshold, wherein the pre-configured time domain threshold includes a set of downlink subframes prior to the reporting subframe; and
measuring and transmitting the CSI report for the determined valid CSI-RS resources of the subset.

5. The method of claim 1 , wherein the channel measurement information for the subset of CSI-RS resources is arranged in the CSI report according to an order of the CSI-RS resources in the feedback configuration signal.

6. The method of claim 1 , wherein the feedback configuration signal includes a precoding indicator to zero or more CSI-RS resources of the plurality of CSI-RS resources that are not precoded, wherein remaining CSI-RS resources of the plurality are precoded.

7. The method of claim 6 , further including:
receiving, at the UE, an instruction to report the channel measurement information based on whether the CSI-RS resource is one of: precoded or not precoded.

8. An apparatus configured for wireless communication, comprising:
means for receiving, at a user equipment (UE), a feedback configuration signal that configures a plurality of channel state information reference signal (CSI-RS) resources in a single channel state information (CSI) process;
means for generating, by the UE, channel measurement information for at least a portion of the plurality of CSI-RS resources; and
means for transmitting, by the UE, a CSI report including the channel measurement information for a subset of CSI-RS resources fewer than all of the plurality of CSI-RS resources, the subset including more than one CSI-RS resource, wherein the channel measurement information includes an indication of an index for each of the more than one CSI-RS resource of the subset for which the channel measurement information is transmitted.

9. The apparatus of claim 8 , further including:
means for determining, by the UE, a spectrum efficiency associated with each of the plurality of CSI-RS resources; and
means for selecting, by the UE, each of the more than one CSI -RS resource of the subset for which the channel measurement information is transmitted based, at least in part, on the determined spectral efficiency.

10. The apparatus of claim 8 , further including:
means for receiving, by the UE, an aperiodic CSI request, wherein a triggering command of the aperiodic CSI request includes a resource indicator identifying one or more of the plurality of CSI-RS resources for the subset.

11. The apparatus of claim 8 , further including:
means for determining, by the UE, a reporting subframe in which the aperiodic CSI measurements are to be reported; and
means for determining, by the UE, whether there are valid CSI-RS resources of the subset within a pre-configured time domain threshold, wherein the pre-configured time domain threshold includes a set of downlink subframes prior to the reporting subframe; and
means for measuring and transmitting the CSI report for the determined valid CSI-RS resources of the subset.

12. The apparatus of claim 8 , wherein the channel measurement information for the subset of CSI-RS resources is arranged in the CSI report according to an order of the CSI-RS resources in the feedback configuration signal.

13. The apparatus of claim 8 , wherein the feedback configuration signal includes a precoding indicator to zero or more CSI-RS resources of the plurality of CSI-RS resources that are not precoded, wherein remaining CSI-RS resources of the plurality are precoded.

14. The apparatus of claim 13 , further including:
means for receiving, at the UE, an instruction to report the channel measurement information based on whether the CSI-RS resource is one of: precoded or not precoded.

Assignees

• Qualcomm Inc
• Wei Chao
• Chen Wanshi
• Gaal Peter
• Zhang Yu

Inventors

• Wei Chao
• Chen Wanshi
• Gaal Peter
• Zhang Yu

Classifications

• H04B7/0632

  Channel quality parameters, e.g. channel quality indicator [CQI] · CPC title

• H04B7/063

  Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection · CPC title

• H04W24/10

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

• H04W24/08

  Testing, {supervising or monitoring} using real traffic · CPC title

• H04L5/005

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