Method and apparatus for performing sequential closed loop multiple input multiple output (MIMO)

• US 20100046665A1
• Filed: 09/09/2009
• Published: 02/25/2010
• Est. Priority Date: 09/30/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: John S. Sadowsky
• Inventors: Sadowsky, John S.
• Granted Patent: US 8,204,145 B2
• Time in Patent Office: Days
• US Class Current: 375/296
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0634 Antenna weights or vector/matrix coefficients
• CPC Class Codes: H04B 7/0636 Feedback format

Abstract

In a communication system using closed loop MIMO, beam forming information may be fed back from a receiver to a transmitter sequentially over a number of frames. The beam forming matrices that are fed back may be quantized.

Claims

1. A method comprising:

receiving a signal Y_i from a MIMO channel, said signal Y_i including data symbols X_i that were matrix multiplied by a beam forming matrix V_i within a remote transmitter before being transmitted into said MIMO channel, said MIMO channel having a channel matrix H_i;

using said signal Y_i to determine a combined channel {tilde over (H)}_i that includes effects of both the beam forming matrix V_i and the channel matrix H_i;

performing a singular value decomposition (SVD) of the combined channel {tilde over (H)}_i to determine a beam forming matrix {tilde over (V)}_i representing a correction that is needed for the beam forming matrix V_i; and

transmitting said beam forming matrix {tilde over (V)}_i to said remote transmitter to be combined with said beam forming matrix V_i to generate a new beam forming matrix V_i+1 for use in a subsequent data transmission from said remote transmitter.