Patent ID: 8451944

Claim:
A method for processing user symbols with a Tomlinson Harashima precoder in a base station (BS) of a multi-user multiple-input multiple-output (MU-MIMO) wireless system having K user terminals (UEs) which communicate with the base station via an uplink (UL) channel and a corresponding downlink (DL) channel, the base station having N antennas and P t as available transmit power, the method comprising: estimating a DL channel matrix H k for each of the K UEs; determining a receiver processing matrix V k for each of the K UEs; computing, based on the DL channel matrix H k and the receiver processing matrix V k , an effective matrix DL channel H eff ; performing a QR decomposition (QRD) of the effective DL channel matrix H eff , with column pivoting in which Q is a unitary matrix and R is an upper triangular matrix; computing Tomlinson Harashima precoder matrices using the unitary matrix Q and the upper triangular matrix R; calculating scalar weights for the UEs using the upper triangular matrix R; processing user symbols by the Tomlinson Harashima precoder having the Tomlinson Harashima precoder matrices to produce an output of filtered vector symbols for the UEs; directing the output of the Tomlinson Harashima precoder to the channel represented by the DL channel matrix through which communications occur in the wireless system with the user terminals; performing additional receiver processing on the transmitted signals at the UEs based on the receiver processing matrix V k for each of the K UEs; and using the scalar weights on the transmitted signals at the UEs.