A low complexity group-wise PIC based mixed-mode MIMO-OFDM system

A. mixed-mode MIMO-OFDM system with the reduced complexity group-wise parallel interference cancellation (G-PIC) algorithm is proposed. At the transmitter, the data stream is first demultiplexed into two groups of substreams, one with capacity constraint via the spatial multiplexing (SM) mode and the other with link quality constraint via the space-time block coding (STBC) mode. At the receiver, a reduced complexity G-PIC is proposed to separate the transmitted streams from different antennas and is based on the following procedures: First, a group-wise MMSE detector and ordering strategy are designed for each group to provide reliable initial decisions for recursive PIC. Second, a recursive group-wise detector, which consists of a conventional PIC, subspace projector and reduced size ML searcher, is developed. Simulation results show that the proposed reduced complexity G-PIC provides almost identical performance compared to the conventional BLAST and relatively lower computational load.