CODEBOOK DESIGN AND STRUCTURE FOR MULTI-GRANULAR FEEDBACK

摘要

FIELD: radio engineering, communication.;SUBSTANCE: invention relates to wireless communication. A first precoding matrix W1 is selected from a first codebook comprising sets of rank-specific precoding matrices. The first codebook is characterised by there being fewer precoding matrices associated with higher ranks than associated with lower ranks, and characterised by precoding matrices associated with ranks above a certain rank being diagonal matrices. The selected first precoding matrix W1 is used to select a rank-specific second precoding matrix W2 from a second codebook, such that the selected first and second precoding matrices form a joint precoder specific to a desired rank. The second codebook is characterised by differently sized precoding matrices associated with each of N total ranks, where N is an integer greater than one. Information on the joint precoder is reported to a network node over an uplink transmission channel.;EFFECT: improved use of codebooks in systems which support high and/or multiple transmission ranks for single-user and multiple-user modes of MIMO communication techniques.;24 cl, 5 dwg, 3 tbl