Multi-granular feedback reporting and feedback processing for precoding in telecommunications

Patent metadata

Field	Value
Publication number	US-9667378-B2
Application number	US-81747610-A
Country	US
Kind code	B2
Filing date	Jun 17, 2010
Priority date	Oct 1, 2009
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

A communications system comprises a second device ( 28 ) and a first device ( 30 ). The first device ( 30 ) is of a type which receives, on a downlink over a radio interface from a second device, precoded information ( 29 ). In an example mode the first device 28 generates a multi-part feedback signal ( 22 ) which is configured to affect content of a precoder matrix ( 40 ) utilized by the second device ( 28 ). On an uplink over the radio interface to the second device, at least two different parts of the multi-part feedback signal are transmitted with two respective different transmission granularities in time and/or frequency.

First claim

What is claimed is:

1. A method in a first device arranged to report feedback information to a second device to affect content of a precoder matrix which is used by the second device in precoding information which is carried over a multiple-input, multiple output (MIMO) channel to the first device, the method comprising:
generating a multi-part feedback signal representing a multi-part precoder matrix structure which is related to channel state information for the MIMO channel;
transmitting to the second device over an uplink channel at least two different parts of the multi-part feedback signal with two respective different transmission granularities in time and frequency, the two different parts of the multi-part feedback signal each being a matrix or a vector, wherein both different parts of the multi-part feedback signal are transmitted at some times and frequencies but only one part of the multi-part feedback signal is transmitted at other times and frequencies; and
wherein a first part of the two different parts of the multi-part feedback signal affects a polarization matrix and a second part of the two different parts of the multi-part feedback signal affects a beamforming vector of the precoder matrix.

2. The method of claim 1 , further comprising receiving from the second device a feedback format command configured to specify the respective different transmission granularities.

3. A method of operating a communications network comprising a first device and a second device, the method comprising:
transmitting information that has been precoded at the second device over a multiple input, multiple output (MIMO) channel to the first device;
at the first device, generating a multi-part feedback signal representing a multi-part precoder matrix structure which is related to channel state information for the MIMO channel;
the first device transmitting over an uplink channel to the second device at least two different parts of the multi-part feedback signal with two respective different transmission granularities in time and frequency, the two different parts of the multi-part feedback signal each being a matrix or a vector, wherein both different parts of the multi-part feedback signal are transmitted by the first device at some times and frequencies but only one part of the multi-part feedback signal is transmitted by the first device at other times and frequencies; and
using the multi-part feedback signal at the second device to affect content of a precoder matrix which is used for precoding of information transmitted over the MIMO channel to the first device,
wherein a first part of the two different parts of the multi-part feedback signal affects a polarization matrix and a second part of the two different parts of the multi-part feedback signal affects a beamforming vector of the precoder matrix.

4. The method of claim 3 , further comprising the second device sending to the first device a feedback format command configured to specify the respective different transmission granularities.

5. A method of operating a communications node, the method comprising:
using a precoder comprising a precoding matrix to transform information that is transmitted over a multiple-input, multiple output (MIMO) channel to a recipient device which receives the transformed information;
receiving a multi-part feedback signal over an uplink channel from the recipient device, the feedback signal representing a multi-part precoder matrix structure related to channel state information for the MIMO channel, at least two different parts of the multi-part feedback signal being received with two respective different transmission granularities in time and frequency, the two different parts of the multi-part feedback signal each being a matrix or a vector, wherein both different parts of the multi-part feedback signal are received at some times and frequencies but only one part of the multi-part feedback signal is received at other times and frequencies; and
using the multi-part feedback signal at the second device to affect precoding of further information transmitted over the MIMO channel to the recipient device,
wherein a first part of the two different parts of the multi-part feedback signal affects a polarization matrix and a second part of the two different parts of the multi-part feedback signal affects a beamforming vector of the precoder matrix.

6. The method of claim 5 , further comprising sending a feedback format command to the recipient device, the format command being configured to specify the respective different transmission granularities.

7. The method of claim 1 , claim 3 , or claim 5 , wherein the precoder matrix structure is obtained as a Kronecker product of two matrices comprising the multi-part matrix structure.

8. The method of claim 1 , claim 3 , or claim 5 ,
wherein the precoder matrix structure comprises the polarization matrix and the beamforming vector, and wherein the matrix for transmission rank r and N T transmit antennas is represented as a Kronecker product W (r) =W (r) poi (x)w BF in which 2×r polarization precoder matrix W (r) pol adjusts relative phases between two groups of antennas and

N
r

2

×
1
⁢
a

beamforming vector w BF adjusts the relative phases within each of two groups of antennas.

9. A first device configured to report feedback information over an uplink channel to a second device using a multi-part feedback signal representing a multi-part precoder matrix structure which is related to channel state information for a multiple-input, multiple output (MIMO) channel with at least two different parts of the multi-part feedback signal being transmitted to the second device with two respective different transmission granularities in time and frequency, the two different parts of the multi-part feedback signal each being a matrix or a vector, wherein both different parts of the multi-part feedback signal are transmitted at some times and frequencies but only one part of the multi-part feedback signal is transmitted at other times and frequencies; and
wherein a first part of the two different parts of the multi-part feedback signal affects a polarization matrix and a second part of the two different parts of the multi-part feedback signal affects a beamforming vector of the precoder matrix.

10. The apparatus of claim 9 , wherein the first device comprises:
a receiver configured to receive information that has been precoded at the second device prior to transmission from the second device over the channel to the first device;
a generator configured to generate the multi-part feedback signal; and
a transmitter configured to transmit to the second device the at least two different parts of the multi-part feedback signal with the two respective different transmission granularities in time and frequency.

11. The apparatus of claim 10 , wherein the receiver is further configured to receive from the second device a feedback format command configured to specify the respective different transmission granularities.

12. A communications network comprising:
a first device configured to report feedback information over an uplink channel to a second device using a multi-part feedback signal representing a multi-part precoder matrix structure which is related to channel state information for a multiple-input, multiple output (MIMO) channel, with at least two different parts of the mu

Assignees

• Jöngren George
• Rahman Muhammad Imadur
• ERICSSON TELEFON AB L M (publ)

Inventors

• Jöngren George
• Rahman Muhammad Imadur

Classifications

• H04L1/0029 Primary

  Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling (power control H04W52/04) · CPC title

• H04B7/0469

  taking special antenna structures, e.g. cross polarized antennas into account · CPC title

• H04B7/0634

  Antenna weights or vector/matrix coefficients · CPC title

• H04B7/0417 Primary

  Feedback systems · CPC title

• H04L1/0693

  Partial feedback, e.g. partial channel state information [CSI] · CPC title