Apparatus and method for transmitting/receiving data in a mobile communication system using multiple antennas

Patent metadata

Field	Value
Publication number	US-RE46951-E
Application number	US-201414518741-A
Country	US
Kind code	E1
Filing date	Oct 20, 2014
Priority date	May 30, 2005
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

An apparatus and method for transmitting/receiving data in a mobile communication system using multiple antennas are provided. A receiver estimates a fading channel of received data, selects a weight set relative to a maximum data transmission rate from at least one weight set with elements of a plurality of orthogonal weight vectors, and transmits feedback information including the selected weight set and channel-by-channel state information to a transmitter. The transmitter demultiplexes data to be transmitted on a basis of the feedback information into at least one sub-data stream, multiplies each sub-data stream by an associated weight, and transmits the data.

First claim

What is claimed is:

1. A mobile communication system using multiple antennas, comprising:
a receiver for estimating a fading channel of received data, selecting a weight set from a plurality of weight sets on a basis of the estimated fading channel, and transmitting feedback information including information indicating the selected weight set and channel-by-channel state information to a transmitter, wherein each weight set has elements of a plurality of orthogonal weight vectors corresponding to weights used in the multiple antennas, with the plurality of orthogonal weight vectors of each weight set having different phases between each other; and the transmitter for demultiplexing data to be transmitted on a basis of the feedback information into at least one sub-data stream, multiplying each sub-data stream by an associated weight, and transmitting the data.

2. The mobile communication system of claim 1 , wherein the receiver comprises:
a downlink channel estimator for estimating a channel state using a pilot channel of the data transmitted from the transmitter; a weight selector for deciding the weight set and weight vectors on a basis of the channel state, and transmitting information about the weight set and information indicating the decided weight vectors to the transmitter; and a subchannel-by-subchannel state estimator for estimating channel states of sub-data streams according to the decided weight vectors and transmitting only information about the channel states of the sub-data streams to the transmitter.

3. The mobile communication system of claim 1 , wherein the receiver comprises:
a downlink channel estimator for estimating a channel state using a pilot channel of the data transmitted from the transmitter; a weight selector for deciding the weight set and weight vectors on a basis of the channel state, and transmitting information indicating the decided weight set and the decided weight vectors to the transmitter; and a subchannel-by-subchannel state estimator for estimating channel states of all weight vectors of the decided weight set and transmitting information about the estimated channel states to the transmitter.

4. The mobile communication system of claim 2 or 3 , wherein the transmitter comprises:
a demultiplexer for demultiplexing a main data stream to be transmitted into the at least one sub-data stream;
at least one channel encoder and modulator for receiving the at least one sub-data stream and independently performing channel coding and modulation processes for the at least one sub-data stream according to a predefined channel coding rate and a predefined modulation scheme;
at least one beamformer for multiplying the at least one channel-coded and modulated sub-data stream by a predefined weight and transmitting the data to the receiver; and
a controller for deciding in advance the number of sub-data streams, the coding rate of the at least one sub-data stream, the modulation scheme, and a weight to be multiplied by each sub-data stream on a basis of the feedback information transmitted from the receiver.

5. The mobile communication system of claim 3 , wherein the subchannel-by-subchannel state estimator transmits information about a “No Transmission” state for an unused channel on a basis of the decided weight vectors.

6. The mobile communication system of claim 1 , wherein the feedback information comprises:
weight set index information for indicating the selected weight set; weight vector information for indicating weight vectors selected from the selected weight set; and channel state information of the at least one sub-data stream.

7. The mobile communication system of claim 1 , wherein the transmitter and the receiver store weight sets and weight vectors according to the number of transmit antennas and the number of weight sets.

8. A method for transmitting/receiving data in a mobile communication system using multiple antennas, the method comprising:
a) estimating a fading channel from a pilot channel of received data in a receiver; b) selecting a weight set from a plurality of weight sets on a basis of the estimated fading channel, wherein each weight set has elements of a plurality of orthogonal weight vectors corresponding to weights used in the multiple antennas, with the plurality of orthogonal weight vectors of each weight set having different phases between each other; c) estimating channel-by-channel state information relative to the selected weight set; d) transmitting feedback information comprising information indicating the selected weight set and the channel-by-channel state information to a transmitter; and e) transmitting, by the transmitter, antenna-by-antenna data on a basis of the feedback information.

9. The method of claim 8 , wherein designing the weight set comprises:
deciding a plurality of weight vectors with a phase difference defined according to the number of transmit antennas and the number of weight sets; and configuring the weight set with orthogonal weight vectors among the decided weight vectors.

10. The method of claim 9 , wherein the phase difference is computed by

2
⁢
π

N
·

n
T

,

where N is the number of weight sets and n T is the number of transmit antennas.

11. The method of claim 8 , wherein designing the weight set comprises:
f-1) deciding a plurality of orthogonal weight vectors among a number of weight sets; and f-2) repeating f-1) a number of times corresponding to the number of weight sets.

12. The method of claim 11 , wherein f-1) comprises:
deciding a reference phase for orthogonal elements of a decided weight vector; and deciding elements with a difference of the reference phase from a first element of the weight vector.

13. The method of claim 8 , wherein the feedback information comprises:
weight set index information for indicating the selected weight set; weight vector information for indicating weight vectors selected from the selected weight set; and channel state information of at least one sub-data stream.

14. The method of claim 8 , wherein the feedback information comprises:
weight set index information for indicating the selected weight set; and channel state information of all sub-data streams relative to the selected weight set.

15. The method of claim 8 , wherein e) comprises:
demultiplexing a main data stream to be transmitted into at least one sub-data stream on the basis of the feedback information; independently performing channel coding and modulation processes for the at least one sub-data stream according to a channel coding rate and a modulation scheme defined on the basis of the feedback information; and multiplying the at least one channel-coded and modulated sub-data stream by a weight defined on the basis of the feedback information and transmitting the data to the receiver.

16. A method for transmitting feedback information from a receiver to a transmitter in a mobile communication system using multiple antennas, the method comprising:
a) estimating a fading channel from a pilot channel of received data and selecting a weight set from a plurality of weight sets on a basis of the estimated fading channel, wherein the weight set has elements of a pl

Assignees

• Samsung Electronics Co Ltd

Inventors

• Han Jin-Kyu
• Kim Dae-Gyun
• Kwon Hwan-Joon
• Kim Dong-Hee
• Kim Youn-Sun
• Kim Yu-Chul
• Mun Cheol

Classifications

• H04L1/06

  using space diversity · CPC title

• H04L1/0026

  Transmission of channel quality indication · CPC title

• H04B7/0626 Primary

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

• H04L1/0009

  by adapting the channel coding (H04L1/1812 takes precedence) · CPC title

• H04B7/0658

  Feedback reduction · CPC title