Patent ID: 9532257
Filing Date: 2016-12-27
CPC Classification: H04B,H04W

Claim Text:
1. A method implemented in a user equipment configured to be used in a multi-user (MU) multiple-input multiple-output (MIMO) wireless communications system, the method comprising: transmitting to a base station a first channel state information (CSI) report determined according to a single-user (SU) MIMO rule; transmitting to the base station a second CSI report determined according to an MU-MIMO rule; and assuming a post scheduling model, wherein the post scheduling model can be expressed as where y 1 represents an N×1 received signal vector on a representative resource element in a resource block (RB), N being the number of receive antennas at the user equipment, {circumflex over (D)} 1 1/2 is a diagonal matrix of effective channel gains, {circumflex over (V)} 1 denotes a semi-unitary matrix whose columns represent preferred channel directions and {circumflex over (V)} 1 + represents Hermitian of {circumflex over (V)} 1 , U 1 and U represent preceding matrices used by the base station to transmit data to the user equipment and a co-scheduled user equipment, respectively, s 1 and s represent transmit symbol vectors intended for the user equipment and the co-scheduled user equipment, respectively, Q 1 is a semi-unitary matrix whose columns lie in the orthogonal complement of {circumflex over (V)} 1 , and R 1 is a matrix which satisfies the Frobenius-norm constraint ∥R 1 ∥ F 2 <ε 1 2 , ε 1 being the residual error norm, and η 1 represents an additive noise vector.