System and Method for Beam-Formed Channel State Reference Signals

Patent metadata

Field	Value
Publication number	US-2016134352-A1
Application number	US-201514880004-A
Country	US
Kind code	A1
Filing date	Oct 9, 2015
Priority date	Nov 6, 2014
Publication date	May 12, 2016
Grant date	—

Abstract

A method for operating a reception point includes receiving a plurality of first directional reference signals spanning a first plane, selecting at least one first directional reference signal from the plurality of received first directional reference signals that meets a first selection criterion, sending a first feedback indicating the selected at least one first directional reference signal, receiving a plurality of second directional reference signals spanning a second plane oriented in accordance with the selected at least one first directional reference signal, selecting at least one second directional reference signal from the plurality of received second directional reference signals that meet a second selection criterion, and sending a second feedback indicating the selected at least one second directional reference signals.

First claim

What is claimed is:

1 . A method for operating a reception point, the method comprising:
receiving, by the reception point, a plurality of first directional reference signals spanning a first plane; selecting, by the reception point, at least one first directional reference signal from the plurality of received first directional reference signals that meets a first selection criterion; sending, by the reception point, a first feedback indicating the selected at least one first directional reference signal; receiving, by the reception point, a plurality of second directional reference signals spanning a second plane oriented in accordance with the selected at least one first directional reference signal; selecting, by the reception point, at least one second directional reference signal from the plurality of received second directional reference signals that meet a second selection criterion; and sending, by the reception point, a second feedback indicating the selected at least one second directional reference signals.

2 . The method of claim 1 , wherein the second feedback further indicates a first subset of the selected one first directional reference signals.

3 . The method of claim 1 , wherein the second feedback also indicates channel quality indicators for the selected at least one second directional reference signals.

4 . The method of claim 1 , wherein each one of the first selection criterion and the second selection criterion comprises one of a received signal strength, a signal to noise ratio (SNR), a signal to interference plus noise ratio (SINR), and a channel capacity.

5 . The method of claim 1 , wherein the first plane is a first one of an azimuth plane and an elevation plane and the second plane is a second one of the azimuth plane and the elevation plane.

6 . The method of claim 1 , wherein the second feedback comprises beam indices corresponding to directional reference signals in a first subset of the selected at least one first directional reference signals and the selected at least one second directional reference signals.

7 . The method of claim 1 , wherein the second feedback comprises at least one of a first precoding matrix indicator for a first subset of the selected at least one first directional reference signals and a second precoding matrix indicator for the selected at least one second directional reference signals.

8 . The method of claim 1 , wherein the second feedback comprises at least one of a channel quality indicator and a rank indicator.

9 . The method of claim 1 , further comprising receiving configuration information for directional reference signals in the first and second planes, the configuration information including at least one of a number of directional reference signals in each plane, a number of repetitions of the directional reference signals in each plane, an indicator of a feedback method for the reception point, a downlink transmission capability of a transmission point, and a resource location for the directional reference signals.

10 . A method for operating a reception point, the method comprising:
receiving, by the reception point, a plurality of first directional reference signals from a transmission point, the plurality of first directional reference signals spanning a first plane; selecting, by the reception point, at least one first directional reference signal from the plurality of received first directional reference signals that meets a first selection criterion; sending, by the reception point, a first feedback indicating the selected at least one first directional reference signal; receiving, by the reception point, a configuration message with an indicator of a number of beam-formed reference signals in a second plane indicating no support for beam-forming in the second plane; and sending, by the reception point, a second feedback indicating a channel quality indicator for a subset of the at least one first directional reference signal.

11 . The method of claim 10 , wherein the method further comprises:
receiving at least one second directional reference signal in accordance with the first feedback; measuring channel state information for the at least one second directional reference signals; and determining the channel quality indicator from the channel state information.

12 . The method of claim 11 , wherein the at least one second directional reference signal and the selected at least one first directional reference signal are one and the same.

13 . A method for operating a transmission point, the method comprising:
sending, by the transmission point, a plurality of first directional reference signals to a reception point, the plurality of first directional reference signals spanning a first plane; receiving, by the transmission point, a first feedback indicating at least one first directional reference signal meeting a first selection criterion and a request to commence operations in a second plane; and when the transmission point is capable of operations in the second plane,
sending, by the transmission point, a plurality of second directional reference signals to the reception point, the plurality of second directional reference signals spanning a second plane oriented in accordance with the at least one first directional reference signal meeting the first selection criterion, and
receiving, by the transmission point, a second feedback indicating at least one second directional reference signal.

14 . The method of claim 13 , further comprising sending configuration information for directional reference signals in the first plane including at least one of a number of directional reference signals in each plane, a number of repetitions of the directional reference signals in each plane, an indication of a feedback method for the reception point, a downlink transmission capability of a transmission point, and a resource location for the directional reference signals.

15 . The method of claim 13 , wherein the second feedback comprises channel quality indicators for the at least one second directional reference signal, and wherein the method further comprises:
selecting transmission parameters in accordance with the channel quality indicators; and sending an indication of the transmission parameters to the reception point.

16 . The method of claim 15 , wherein the indication of the transmission parameters comprises at least one of a modulation and coding scheme (MCS) level, a beam index of a directional reference signal selected in accordance with the channel quality indicators, a precoding matrix indicator (PMI), and a rank indicator (RI).

17 . The method of claim 13 , further comprising when the transmission point is not capable of operations in the second plane:
sending a configuration message with an indicator of a number of beam-formed reference signals in a second plane indicating no support for beam-forming in the second plane; and receiving a third feedback indicating a channel quality indicator for a subset of the at least one first directional reference signal.

18 . The method of claim 17 , further comprising sending the at least one directional reference signal in accordance with the first feedback.

19 . A reception point comprising:
a processor; and a computer readable storage medium storing programming for execution by the processor, the programming including instructions to configure the reception point to
receive a plurality of first directional reference signals spanning a first plane,
se

Assignees

• Futurewei Technologies Inc

Inventors

• Stirling-Gallacher Richard

Classifications

• H04L5/0057

  Physical resource allocation for CQI · CPC title

• H04L5/005

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

• H04L27/261

  Details of reference signals · CPC title

• H04W16/28

  using beam steering · CPC title

• H04B7/0639

  Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection · CPC title