Enhanced CSI feedback for FD-MIMO

Patent metadata

Field	Value
Publication number	US-11611378-B2
Application number	US-202017028974-A
Country	US
Kind code	B2
Filing date	Sep 22, 2020
Priority date	Jan 19, 2015
Publication date	Mar 21, 2023
Grant date	Mar 21, 2023

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 single channel state information (CSI) process identifying azimuth and elevation CSI reference signal (CSI-RS) ports;
transmitting, by the UE, a precoding matrix indicator (PMI) report, wherein the PMI report includes a first PMI associated with the azimuth CSI-RS ports, a second PMI associated with the elevation CSI-RS ports, and a low rank indicator, wherein at least one of the first PMI and the second PMI is assigned a low rank, and wherein the low rank indicator denotes which of the first PMI or the second PMI is assigned the low rank; and
transmitting, by the UE, a CSI report with measurements based on the azimuth and elevation CSI-RS ports.

2. The method of claim 1 , wherein the PMI report is arranged according to a fixed order of the low rank indicator, the first PMI, and the second PMI.

3. The method of claim 1 , wherein the CSI report includes a rank indicator (RI) and a channel quality indicator (CQI), wherein the CQI and RI are determined based on the first PMI, the second PMI, and the low rank indicator.

4. The method of claim 1 , further including:
determining, by the UE, the low rank indicator for the first PMI and the second PMI based, at least in part, on the feedback configuration signal configuring the single CSI process, wherein the PMI report further includes the low rank indicator.

5. An apparatus configured for wireless communication, the apparatus comprising:
at least one processor; and
a memory coupled to the at least one processor,
wherein the at least one processor is configured to:
receive, at a user equipment (UE), a feedback configuration signal that configures a single channel state information (CSI) process identifying azimuth and elevation CSI reference signal (CSI-RS) ports;
transmit, by the UE, a precoding matrix indicator (PMI) report, wherein the PMI report includes a first PMI associated with the azimuth CSI-RS ports and a second PMI associated with the elevation CSI-RS ports, and a low rank indicator, wherein at least one of the first PMI and the second PMI is assigned a low rank, and wherein the low rank indicator denotes which of the first PMI or the second PMI is assigned the low rank; and
transmit, by the UE, a CSI report with measurements based on the azimuth and elevation CSI-RS ports.

6. The apparatus of claim 5 , wherein the PMI report is arranged according to a fixed order of the low rank indicator, the first PMI, and the second PMI.

7. The apparatus of claim 5 , wherein the CSI report includes a rank indicator (RI) and a channel quality indicator (CQI), wherein the CQI and RI are determined based on the first PMI, the second PMI, and the low rank indicator.

8. The apparatus of claim 5 , wherein the at least one processor is further configured to:
determine, by the UE, the low rank indicator for the first PMI and the second PMI based, at least in part, on the feedback configuration signal configuring the single CSI process, wherein the PMI report further includes the low rank indicator.

9. An apparatus for wireless communication, comprising:
means for receiving, at a user equipment (UE), a feedback configuration signal that configures a single channel state information (CSI) process identifying azimuth and elevation CSI reference signal (CSI-RS) ports;
means for transmitting, by the UE, a precoding matrix indicator (PMI) report, wherein the PMI report includes a first PMI associated with the azimuth CSI-RS ports and a second PMI associated with the elevation CSI-RS ports, and a low rank indicator, wherein at least one of the first PMI and the second PMI is assigned a low rank, and wherein the low rank indicator denotes which of the first PMI or the second PMI is assigned the low rank; and
means for transmitting, by the UE, a CSI report with measurements based on the azimuth and elevation CSI-RS ports.

10. The apparatus of claim 9 , wherein the PMI report is arranged according to a fixed order of the low rank indicator, first PMI, and second PMI.

11. The apparatus of claim 9 , wherein the CSI report includes a rank indicator (RI) and a channel quality indicator (CQI), wherein the CQI and RI are determined based on the first PMI, the second PMI, and the low rank indicator.

12. The apparatus of claim 9 , further including:
means for determining, by the UE, the low rank indicator for the first PMI and the second PMI based, at least in part, on the feedback configuration signal configuring the single CSI process, wherein the PMI report further includes the low rank indicator.

13. The method of claim 1 , wherein the first PMI and the second PMI are combinable to form a whole channel precoding matrix.

14. The method of claim 13 , wherein a correlation procedure is used to combine the first PMI and the second PMI to form the whole channel precoding matrix.

15. The method of claim 14 , wherein the correlation procedure comprises a Kronecker product.

Assignees

• Qualcomm Inc

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