Method and apparatus for precoding channel state information reference signal

Patent metadata

Field	Value
Publication number	US-2016156397-A1
Application number	US-201514800305-A
Country	US
Kind code	A1
Filing date	Jul 15, 2015
Priority date	Nov 17, 2014
Publication date	Jun 2, 2016
Grant date	—

Abstract

A method for operating a base station includes allocating at least one respective CSI-RS port to each of a plurality of user equipments (UEs), precoding the at least one respective CSI-RS port with a first respective precoding matrix for each of the plurality of UEs, transmitting the at least one respective CSI-RS port precoded with the first respective precoding matrix through a channel to each of the plurality of UEs, receiving an index of a second respective precoding matrix from each of the plurality of UEs, wherein the second respective precoding matrix is determined according to the at least respective one CSI-RS port precoded with the first precoding matrix as received through the channel by each of the plurality of UEs, and precoding respective transmission data with the first respective precoding matrix and the second respective precoding matrix to each of the plurality of UEs.

First claim

What is claimed:

1 . A method for operating a Base Station (BS), the method comprising:
allocating at least one respective CSI-RS port to each of a plurality of User Equipments (UEs); precoding the at least one respective CSI-RS port with a first respective precoding matrix for each of the plurality of UEs; transmitting the at least one respective CSI-RS port precoded with the first respective precoding matrix through a channel to each of the plurality of UEs; receiving an index of a second respective precoding matrix from each of the plurality of UEs; and precoding respective data transmission with the first respective precoding matrix and the second respective precoding matrix to each of the plurality of UEs.

2 . The method of claim 1 , wherein the first respective matrix is determined according to either a measurement of at least one respective uplink (UL) signal or a respective CSI feedback from each of the plurality of UEs, wherein the second respective precoding matrix is determined according to the at least respective one CSI-RS port precoded with the first precoding matrix as received through the channel by each of the plurality of UEs.

3 . The method of claim 1 , wherein a part of the plurality of UEs forms at least one group, and the at least one respective CSI-RS port is assigned to each group.

4 . The method of claim 1 , wherein the first respective precoding matrix is a long term wideband precoding matrix, and the respective second precoding matrix is a short term precoding matrix.

5 . The method of claim 1 , wherein the at least one CSI-RS antenna port comprises a linear combination of a plurality of cell-specific CSI-RS ports, wherein the linear combination is responsive to a first feedback from the UE, or a measurement of an uplink transmission from the UE.

6 . The method of claim 3 , wherein a number of the linear combination of the plurality of cell-specific CSI-RS ports is responsive to a second feedback from the UE, or a measurement of an uplink transmission from the UE.

7 . The method of claim 3 , a codebook for the second respective precoding matrix is determined according to a number of the at least one respective CSI-RS antenna port.

8 . A base station (BS), comprising:
a transceiver; and a processor configured to:
allocate at least one respective CSI-RS port to each of a plurality of User Equipments (UEs);
precode the at least one respective CSI-RS port with a first respective precoding matrix for each of the plurality of UEs;
cause the transceiver to transmit the at least one respective CSI-RS port precoded with the first respective precoding matrix through a channel to each of the plurality of UEs;
cause the transceiver to receive an index of a second respective precoding matrix from each of the plurality of UEs; and
precode respective data transmission with the first respective precoding matrix and the second respective precoding matrix to each of the plurality of UEs.

9 . The base station of claim 8 , wherein the first respective matrix is determined according to either a measurement of at least one respective uplink (UL) signal or a respective CSI feedback from each of the plurality of UEs, wherein the second respective precoding matrix is determined according to the at least respective one CSI-RS port precoded with the first precoding matrix as received through the channel by each of the plurality of UEs.

10 . The base station of claim 8 , wherein a part of the plurality of UEs forms at least one group, and the at least one respective CSI-RS port is assigned to each group.

11 . The base station of claim 8 , wherein the first respective precoding matrix is a long term wideband precoding matrix, and the respective second precoding matrix is a short term precoding matrix.

12 . The base station of claim 8 , wherein the at least one CSI-RS antenna port comprises a linear combination of a plurality of cell-specific CSI-RS ports, wherein the linear combination is responsive to a first feedback from the UE, or a measurement of an uplink transmission from the UE.

13 . The base station of claim 12 , wherein a number of the linear combination of the plurality of cell-specific CSI-RS ports is responsive to a second feedback from the UE, or a measurement of an uplink transmission from the UE.

14 . The base station of claim 8 , a codebook for the second respective precoding matrix is determined according to a number of the at least one respective CSI-RS antenna port.

15 . A User Equipment (UE), comprising:
a transceiver; and a processor configured to:
cause the transceiver to receive at least one CSI-RS port precoded with a first precoding matrix through a channel from a base station;
determine a second precoding matrix according to the received at least one CSI-RS port precoded with the first precoding matrix;
cause the transceiver to transmit an index for the determined second precoding matrix to the BS; and
cause the transceiver to receive data transmission with the first precoding matrix and the second precoding matrix from the base station.

16 . The UE of claim 15 , wherein the first matrix is determined according to either a measurement of at least one uplink (UL) signal or a CSI feedback from each of the plurality of UEs.

17 . The UE of claim 15 , wherein a part of the plurality of UEs forms at least one group, and the at least one CSI-RS port is assigned to each of the at least one group.

18 . The UE of claim 15 , wherein the first precoding matrix is a long term wideband precoding matrix, and the second precoding matrix is a short term precoding matrix.

19 . The UE of claim 15 , wherein the at least one CSI-RS antenna port comprises a linear combination of a plurality of cell-specific CSI-RS ports, wherein the linear combination is responsive to a first feedback from the UE, or a measurement of an uplink transmission from the UE.

20 . The UE of claim 19 , wherein a number of the linear combination of the plurality of cell-specific CSI-RS ports is responsive to a second feedback from the UE, or a measurement of an uplink transmission from the UE.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Onggosanusi Eko
• Zhang Jianzhong
• Li Yang
• Nam Young-Han
• Ng Boon Loong

Classifications

• H04B7/0456 Primary

  Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting · CPC title

• H04W24/08

  Testing, {supervising or monitoring} using real traffic · 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

• H04B7/0626

  Channel coefficients, e.g. channel state information [CSI] · CPC title

• H04L5/005

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