Quantization of channel state information in multiple antenna systems

A method performed by a transmitter having multiple antennas for transmission over multiple wireless channels, the method comprising:nstoring pre-calculated channel precoding matrices at the transmitter;receiving multiple indices of quantized channel state information at the transmitter from a plurality of receivers;selecting a channel precoding matrix from the stored channel precoding matrices based at least on the multiple indices of quantized channel state information received from the plurality of receivers, wherein the selecting is further based at least on a predefined ratio of metrics determined by a combination of the precoding matrices indicated by quantized channel state information received from the plurality of receivers; andtransmitting over the multiple channels to the plurality of receivers using the selected channel precoding matrix.

A method performed by a receiver for communication with a transmitter that transmits on at least n>1 antennas, the method comprising:nestimating multiple antenna channels between the transmitter and the receiver;decomposing the estimated multiple antenna channels to form a matrix of orthogonal modes;selecting a channel precoding matrix from a pre-calculated set of channel precoding matrices based at least on capacity;analyzing the estimated multiple antenna channels to obtain orthogonal mode gains;quantizing the orthogonal mode gains;determining respective singular values of the orthogonal modes;testing entries in a codebook of transmitter power division matrices in combination with testing the entries in the codebook of transmitter precoding matrices to select the precoding matrix and a transmitter power division matrix; andsending quantized channel state information and an index of the power division matrix to the transmitter, wherein the quantized channel state information includes an indication about channel mode gains and the selected channel precoding matrix, to enable use of the selected channel precoding matrix by the transmitter in further transmissions to the one or more receivers.

A method of transmission between a transmitter that transmits on at least n>1 antennas and a plurality of receivers in a wireless multiple channel system, the method comprising:neach receiver of the plurality of receivers:nestimating the respective multiple channels, decomposing the estimated channels to form a matrix of orthogonal modes, testing entries in a codebook of channel precoding matrices for a match with the estimated channels, and sending an index of a selected channel precoding matrix to the transmitter, to enable the transmitter to choose a channel precoding matrix in further transmissions to the plurality of receivers based at least on the indexes transmitted from the plurality of receivers;estimating gains of the selected orthogonal modes, quantizing the gains, and sending an indication of the quantized gains of the selected orthogonal modes to the receiver; anddetermining respective singular values of the orthogonal modes, testing entries in a codebook of receiver power division matrices in combination with testing the entries in the codebook of channel precoding matrices to select the precoding matrix and a transmitter power division matrix, and sending an index of the power division matrix back to the transmitter.

A method of communications over multiple wireless channels in a multiple antenna system having one or more receivers, the method comprising:neach receiver storing pre-calculated codebook indexes of channel precoding matrices, the codebook indexes comprising at least a first set of indexes and a second set of indexes nested within the first set;each receiver selecting at least a respective first codebook index from the first set of indexes and transmitting the respective first codebook index to the transmitter;at least one of the receivers receiving a first transmission from the transmitter, the transmission using a precoding matrix based at least upon a corresponding first codebook index;the at least one of the receivers, upon receiving the first transmission, selecting a second codebook index from the second set of indexes and transmitting the second codebook index to the transmitter, wherein the second codebook index is based at least upon an estimate of a rate of change of the multiple wireless channels; andthe at least one of the receivers receiving further transmissions from the transmitter, the further transmissions using a precoding matrix based at least on the corresponding first codebook index and the second codebook index.

A method performed by a receiver for communication with a base station that transmits via multiple antennas, the method comprising:nreceiving a transmission from the base station, wherein the transmission is sent via a plurality of sub-carriers and wherein multiple sub-carriers of the plurality of sub-carriers are grouped into groups;selecting at least one precoding matrix, from a subset of a predefined codebook, corresponding to a signal received via at least one of the groups; andreporting a respective index corresponding to each of the at least one precoding matrix using relatively fewer bits than reporting an index selected from all of the predefined codebook.

A receiver configured to communicate with a base station that transmits via multiple antennas, the receiver comprising circuitry configured to:nreceive a transmission from the base station, wherein the transmission is sent via a plurality of sub-carriers and wherein multiple sub-carriers of the plurality of sub-carriers are grouped into groups;select at least one precoding matrix, from a subset of a predefined codebook, corresponding to a signal received via at least one of the groups; andreport a respective index corresponding to each of the at least one precoding matrix using relatively fewer bits than reporting an index selected from all of the predefined codebook.