MULTI-USER MIMO-SDMA FOR FINITE RATE FEEDBACK SYSTEMS

• US 20140192915A1
• Filed: 05/06/2013
• Published: 07/10/2014
• Est. Priority Date: 01/05/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Mundarath, Jayakrishnan C., Kotecha, Jayesh H.
• Granted Patent: US 9,225,398 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A multi-user MIMO downlink beamforming system with limited feedback (200) is provided to enable precoding for multi-stream transmission, where a channel codeword (u_i) and one or more channel quality indicator values (CQI_A, CQI_B) are computed at the user equipment (201.i) on the basis of maximizing a predetermined SINR performance metric (p_i) which estimates file receive signal-to-noise-ratio (SINR) at the user equipment (201.i). The computed codeword (u_i) and CQI values (or differential values related thereto) are quantized and fed back to help the base station (210) which applies a correction to the appropriate CQI value in the course of designing the transmit beamforming vectors w and determining the appropriate modulation and coding level to be used for downlink data transmission.

Claims

1-23. -23. (canceled)

24. A method of operating a mobile wireless communications device operable in a multiple input, multiple output (MIMO) space division multiple access (SDMA) communications mode, the method comprising:

receiving one or more signals from a base station at the mobile wireless communications device;

determining a parameter related to a transmission channel based at least in part on the one or more signals;

determining (i) a receive beamforming vector for the transmission channel and (ii) a codeword using a predetermined channel quality indicator (CQI) metric; and

transmitting feedback information to a base station, the feedback information being representative of at least the codeword.

25. A mobile wireless communications device operable in a multiple input, multiple output (MIMO) space division multiple access (SDMA) communications mode, the device comprising:

processing apparatus; and

logic in data communication with the processing apparatus, the logic configured to;

receive one or more signals from a base station;

determine a parameter related to a transmission channel based at least in part on the one or more signals;

determine a receive beamforming vector for the transmission channel;

determine a codeword using a predetermined channel quality indicator (CQI) metric; and

transmit feedback information to the base station, the feedback information being representative of at least the codeword.

26. A mobile wireless communications system, comprising:

a base station; and

a mobile device operable in a multiple input, multiple output (MIMO) space division multiple access (SDMA) communications mode, the device comprising;

processing apparatus; and

logic in data communication with the processing apparatus, the logic configured to;

receive one or more signals from the base station;

determine a parameter related to a transmission channel based at least in part on the one or more signals;

determine a receive beamforming vector for the transmission channel;

determine a codeword using a predetermined channel quality indicator (CQI) metric; and

transmit feedback information to the base station, the feedback information being representative of at least the codeword.