Multiuser space-time code for OFDM/SDMA systems [WLAN applications]

A combined OFDM/SDMA-DAU (double antenna users) system is investigated, where the base station is installed with multiple antennas and each user terminal is equipped with two antennas. A multiuser space-time code algorithm with channel state information at the transmitter is presented for the downlink of the OFDM/SDMA-DAU system, where the receivers can achieve multiuser interference suppression and diversity by a low-complexity and efficient decoding approach. Simulation results verify that the OFDM/SDMA-DAU system, benefitting from the advantages of OFDM, SDMA and space-time coding, outperforms the OFDM/SDMA-SAU (single antenna users) system with respect to not only the BER performance but also the transmitted power fluctuation.