System and Method for Employing a Six-Bit Rank 1 Codebook for Four Transmit Antennas

A method for communications device operation, the method comprising:

• estimating a communications channel between the communications device and a controller serving the communications device, thereby producing a channel estimate;
• performing a first stage quantization of the channel estimate using a codebook, wherein the codebook comprises a plurality of first level codewords, wherein each first level codeword has a plurality of subsidiary codewords, and wherein the first stage quantization uses only the plurality of first level codewords, thereby producing a selected first level codeword;
• transmitting a first index corresponding to the selected first level codeword from the codebook to the controller;
• performing a second stage quantization of the channel estimate using the codebook, wherein the second stage quantization uses the entirety of the codebook, thereby producing a selected codeword;
• and
• transmitting a second index corresponding to the selected codeword from the codebook to the controller.

A method for controller operation, the method comprising:

• receiving a first channel state information (CSI) from a communications device, wherein the first CSI comprises a first index to a first level codeword in a codebook, wherein the codebook comprises a plurality of first level codewords, wherein each first level codeword has a plurality of subsidiary codewords;
• reconstructing a first channel estimate using the codebook and the first index;
• adjusting transmission circuitry in the controller using the reconstructed first channel estimate;
• receiving a second CSI from a communications device, wherein the second CSI comprises a second index to a codeword in the codebook;
• in response to determining that the first index is different from the second index,
• reconstructing a second channel estimate using the codebook and the second index, and
• adjusting transmission circuitry in the controller using the reconstructed second channel estimate;
• transmitting a first transmission to the communications device using the adjusted transmission circuitry.