PRECODER STRUCTURE FOR MIMO PRECODING
First Claim
1. A method in a wireless communication transceiver, wherein another transceiver precodes transmissions to the transceiver based at least in part on the transceiver sending channel state information to the other transceiver that includes precoder information and wherein the method is characterized by:
 selecting entries from one or more codebooks as a selected conversion precoder and a selected tuning precoder, or as a selected overall precoder corresponding to a selected conversion precoder and a selected tuning precoder; and
transmitting indications of the selected entries as said precoder information included in the channel state information;
wherein the one or more codebooks include entries comprising N_{T}Q different conversion precoders, N_{T }being the number of transmit antenna ports and Q being an integer value, and entries comprising a number of corresponding tuning precoders, or include entries comprising a plurality of overall precoders with each overall precoder comprising the product of a conversion precoder and a tuning precoder; and
wherein each said conversion precoder out of said N_{T}Q different entries comprises a block diagonal matrix in which each block comprises a DFTbased antennasubgroup precoder that corresponds to a subgroup of N_{T }transmit antenna ports at the transceiver and provides N_{T}Q different DFT based beams for the corresponding subgroup, where the N_{T}Q different conversion precoders together with one or more of the tuning precoders, correspond to a set of N_{T}Q different overall precoders, wherein each overall precoder represents a sizeN_{T }DFTbased beam over the N_{T }transmit antenna ports,wherein said one or more codebooks includes conversion and tuning precoders or corresponding overall precoders for multiple transmission ranks, andwherein for transmission rank r>
2the tuning precoder has 2┌
r/2┐
rows and r columns, where r is the transmission rank;
all nonzero elements of the tuning precoder are constant modulus;
every column of the tuning precoder has exactly two nonzero elements;
every row of the tuning precoder has exactly two nonzero elements; and
two columns of the tuning precoder having nonzero elements in the same two rows are orthogonal to each other.
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Accused Products
Abstract
The teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for certain codebook reuse across different transmission scenarios, including for transmission from a single Uniform Linear Array (ULA) of transmit antennas and transmission from crosspolarized subgroups of such antennas. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder includes antennasubgroup precoders of size N_{T}/2, where N_{T }represents the number of overall antenna ports considered. Correspondingly, the tuning precoder controls the offset of beam phases between the antennasubgroup precoders, allowing the conversion precoder to be used with crosspolarized arrays of N_{T}/2 antenna elements and with copolarized arrays of N_{T }antenna elements.
1 Citation
15 Claims

1. A method in a wireless communication transceiver, wherein another transceiver precodes transmissions to the transceiver based at least in part on the transceiver sending channel state information to the other transceiver that includes precoder information and wherein the method is characterized by:

selecting entries from one or more codebooks as a selected conversion precoder and a selected tuning precoder, or as a selected overall precoder corresponding to a selected conversion precoder and a selected tuning precoder; and transmitting indications of the selected entries as said precoder information included in the channel state information; wherein the one or more codebooks include entries comprising N_{T}Q different conversion precoders, N_{T }being the number of transmit antenna ports and Q being an integer value, and entries comprising a number of corresponding tuning precoders, or include entries comprising a plurality of overall precoders with each overall precoder comprising the product of a conversion precoder and a tuning precoder; and wherein each said conversion precoder out of said N_{T}Q different entries comprises a block diagonal matrix in which each block comprises a DFTbased antennasubgroup precoder that corresponds to a subgroup of N_{T }transmit antenna ports at the transceiver and provides N_{T}Q different DFT based beams for the corresponding subgroup, where the N_{T}Q different conversion precoders together with one or more of the tuning precoders, correspond to a set of N_{T}Q different overall precoders, wherein each overall precoder represents a sizeN_{T }DFTbased beam over the N_{T }transmit antenna ports, wherein said one or more codebooks includes conversion and tuning precoders or corresponding overall precoders for multiple transmission ranks, and wherein for transmission rank r>
2the tuning precoder has 2┌
r/2┐
rows and r columns, where r is the transmission rank;all nonzero elements of the tuning precoder are constant modulus; every column of the tuning precoder has exactly two nonzero elements; every row of the tuning precoder has exactly two nonzero elements; and two columns of the tuning precoder having nonzero elements in the same two rows are orthogonal to each other.  View Dependent Claims (2, 3, 4, 5, 6)


7. A wireless communication transceiver configured to send channel state information to another wireless communication transceiver that precodes transmissions to the transceiver based at least in part on the channel state information, said transceiver including a receiver for receiving signals from the other transceiver and a transmitter for transmitting signals to the other transceiver, including transmitting signals conveying said channel state information, wherein said transceiver is characterized by:

a memory storing one or more codebooks including entries comprising N_{T}Q different conversion precoders, N_{T }being the number of transmit antenna ports, and Q being an integer value, and entries comprising a number of corresponding tuning precoders, or entries comprising a plurality of overall precoders, with each overall precoder comprising the product of a conversion precoder and a tuning precoder, wherein each said conversion precoder out of said N_{T}Q different entries comprises a block diagonal matrix in which each block comprises a DFTbased antennasubgroup precoder that corresponds to a subgroup of N_{T }transmit antenna ports at the transceiver and provides N_{T}Q different DFT based beams for the corresponding subgroup, where Q is an integer value and where the N_{T}Q different conversion precoders, together with one or more of the tuning precoders, correspond to a set of N_{T}Q different overall precoders wherein each overall precoder represents a sizeN_{T }DFTbased beam over the N_{T }transmit antennas ports; and a precoding feedback generator configured to select entries from the one or more codebooks as a selected conversion precoder and a selected tuning precoder, or as a selected overall precoder corresponding to a selected conversion precoder and a selected tuning precoder; said precoding feedback generator further configured to transmit, via said transmitter, indications of the selected entries as precoder information included in said channel state information, wherein said one or more codebooks includes conversion and tuning precoders or corresponding overall precoders for multiple transmission ranks, and wherein for transmission rank r>
2;the tuning precoder has 2┌
r/2┐
rows and r columns, where r is the transmission rank;all of the tuning precoder nonzero elements are constant modulus; every column of the tuning precoder has exactly two nonzero elements; every row of the tuning precoder has exactly two nonzero elements; and two columns of the tuning precoder having nonzero elements in the same two rows are orthogonal to each other.  View Dependent Claims (8, 9)


10. A method of precoding multiantenna transmissions from a wireless communication transceiver to another wireless communication transceiver, based at least in part on receiving channel state information from the other transceiver that includes precoder information, said method characterized by:

identifying the precoder information by selecting entries from one or more codebooks known at the transceiver responsive to selection indications included in the channel state information; and precoding a transmission to the other transceiver based at least in part on the precoder information; wherein the one or more codebooks as known by the transceiver include entries comprising N_{T }Q different conversion precoders, N_{T }being the number of transmit antenna ports and Q being an integer value, and entries comprising a number of corresponding tuning precoders, or entries comprising a plurality of overall precoders with each overall precoder comprising the product of a conversion precoder and a tuning precoder, and wherein each said conversion precoder out of said N_{T }Q different entries comprises a block diagonal matrix in which each block comprises a DFTbased antennasubgroup precoder that corresponds to a subgroup of N_{T }transmit antenna ports and provides N_{T }Q different DFT based beams for the corresponding subgroup, wherein the N_{T }Q different conversion precoders, together with one or more of the tuning precoders, correspond to a set of N_{T }Q different overall precoders, wherein each overall precoder represents a size N_{T }DFTbased beam over the N_{T }transmit antenna ports, wherein said one or more codebooks includes conversion and tuning precoders or corresponding overall precoders for multiple transmission ranks, and wherein for transmission rank r>
2;the tuning precoder has 2┌
r/2┐
rows and r columns, where r is the transmission rank;all nonzero elements of the tuning precoder are constant modulus; every column of the tuning precoder has exactly two nonzero elements; every row of the tuning precoder has exactly two nonzero elements; and two columns of the tuning precoder having nonzero elements in the same two rows are orthogonal to each other.  View Dependent Claims (11, 12)


13. A wireless communication transceiver configured to precode multiantenna transmissions to another wireless communication transceiver based at least in part on receiving channel state information from the other transceiver, said transceiver including a transmitter and a plurality of antennas for transmitting said multiantenna transmissions and a receiver for receiving the channel state information, and wherein the transceiver is characterized by:

a memory storing one or more codebooks including entries comprising N_{T}Q different conversion precoders, N_{T }being the number of transmit antenna ports and Q being an integer value, and entries comprising a number of corresponding tuning precoders, or entries comprising a plurality of overall precoders, with each overall precoder comprising the product of a conversion precoder and a tuning precoder, wherein each said conversion precoder out of said N_{T}Q different entries comprises a block diagonal matrix in which each block comprises a DFTbased antennasubgroup precoder that corresponds to a subgroup of N_{T }transmit antenna ports and provides N_{T}Q different DFT based beams for the corresponding subgroup, where the N_{T}Q different conversion precoders together with one or more of the tuning precoders correspond to a set of N_{T}Q different overall precoders, wherein each overall precoder represents a sizeN_{T }DFTbased beam over the N_{T }transmit antenna ports; a feedback processor configured to identify precoder information from the other receiver based on using selection indications included in the channel state information to identify from the one or more codebooks selected conversion and tuning precoders or a selected overall precoder corresponding to selected conversion and tuning precoders; and a precoding controller and associated precoding circuit configured to precode the transmission to the other transceiver, based at least in part on the precoder information, wherein said one or more codebooks includes conversion and tuning precoders or corresponding overall precoders for multiple transmission ranks, and wherein for transmission rank r>
2;the tuning precoder has 2┌
r/2┐
rows and r columns, where r is the transmission rank;all nonzero elements of the tuning precoder are constant modulus; every column of the tuning precoder has exactly two nonzero elements; every row of the tuning precoder has exactly two nonzero elements, and two columns of the tuning precoder having nonzero elements in the same two rows are orthogonal to each other.  View Dependent Claims (14, 15)

1 Specification