• US 20180076863A1
  • Filed: 11/27/2017
  • Published: 03/15/2018
  • Est. Priority Date: 04/07/2010
  • Status: Active Grant
First Claim
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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 NTQ different conversion precoders, NT 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 NTQ different entries comprises a block diagonal matrix in which each block comprises a DFT-based antenna-subgroup precoder that corresponds to a subgroup of NT transmit antenna ports at the transceiver and provides NTQ different DFT based beams for the corresponding subgroup, where the NTQ different conversion precoders together with one or more of the tuning precoders, correspond to a set of NTQ different overall precoders, wherein each overall precoder represents a size-NT DFT-based beam over the NT 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┌


    rows and r columns, where r is the transmission rank;

    all non-zero elements of the tuning precoder are constant modulus;

    every column of the tuning precoder has exactly two non-zero elements;

    every row of the tuning precoder has exactly two non-zero elements; and

    two columns of the tuning precoder having non-zero elements in the same two rows are orthogonal to each other.

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