A Downlink Multiuser MIMO OFDM Decomposition Method in Frequency Selective Fading Channels

A MU MIMO OFDM decomposition method for frequency selective fading channels is investigated in this paper. In the method, multipath is first decomposed into parallel single paths through OFDM, and then the multi-user signal is decomposed into parallel single users using the pre-coding method for a flat fading MIMO channel. We also prove both in theory and simulations that the MU MIMO OFDM channel after the decomposition has the same distribution as that of a regular SU MIMO OFDM channel with the same size. Simulation results match the theoretical analysis.