Method and apparatus for processing feedback in a wireless communication system

• US 8,798,212 B2
• Filed: 10/30/2007
• Issued: 08/05/2014
• Est. Priority Date: 10/30/2006
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Pan, Kyle Jung-Lin, Tsai, Allan Yingming
• Primary Examiner(s): Ghulamali, Qutbuddin
• Application Number:
  US11/928,198
• Publication Number:
  US 20080112500A1
• Time in Patent Office: 2,471 Days
• Field of Search: 375/346, 375/299, 375/347, 375/267, 375/286, 375/341, 375/342, 375/345
• US Class Current: 375/346
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0641 Differential feedback
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04L 1/0693 Partial feedback, e.g. partial channel state information [CSI]
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0246 with factorisation

Abstract

A method and apparatus for processing feedback implemented in a wireless transmit/receive unit (WTRU) comprises estimating a channel matrix. The effective channel is calculated and a precoding matrix is selected. Feedback bits are generated and transmitted.

Claims

1. A method for processing feedback implemented in a wireless transmit/receive unit (WTRU), the method comprising:

estimating a channel matrix;

calculating an effective channel;

selecting a precoding matrix from a set of precoding matrices, the set of precoding matrices being constructed using a discrete Fourier transform (DFT) matrix multiplied with at least two different phase shifts;

generating feedback bits by the WTRU; and

transmitting the feedback bits by the WTRU.

2. The method of claim 1 further including selecting the precoding matrix based upon a metric, wherein the metric includes any one of the following:

signal to interference noise ratio (SINR), throughput, block error rate (BER), frame error rate, and channel capacity.

3. The method of claim 1 wherein the effective channel is a multiplication of the channel estimate with one or more precoding matrices of the set of precoding matrices.

4. The method of claim 1 wherein the selecting a precoding matrix includes calculating the precoding matrix from the channel matrix estimate.

5. The method of claim 4 wherein the selecting a precoding matrix further comprises:

quantizing the precoding matrix using a predetermined codebook.

6. The method of claim 1 wherein the feedback bits include a codeword index.

7. A method for processing feedback implemented in a wireless transmit/receive unit (WTRU), the method comprising:

constructing a set of precoding matrices using a discrete Fourier transform (DFT) matrix multiplied with at least two different phase shifts;

selecting a precoding matrix from the set of precoding matrices;

computing a differential precoding matrix or delta matrix from the selected precoding matrix;

quantizing the differential precoding matrix or delta matrix;

generating feedback bits from the quantized differential precoding matrix or delta matrix by the WTRU; and

transmitting the feedback bits by the WTRU.

8. The method of claim 7 wherein the feedback bits include a codeword index.