Performance of space-division multiple-access systems communicating over Nakagami fading channels

The performance of a space-division multiple-access (SDMA) system is investigated, when the space-time block coded signals, based on two transmit antennas, are transmitted over Nakagami-m fading channels. The receiver employs multiple receive antennas, each consisting of several antenna array elements. In order to gain insight into the multiuser interference resistance of SDMA systems, we consider the employment of a single-user detector. Our simulation results show that in SDMA systems, the interfering signals arriving from directions different from that of the desired signal can be efficiently suppressed with the aid of the antenna arrays. However, due to the time-varying characteristics of wireless channels, aggressive interference may be imposed on the desired signal, when the interfering signals have a similar direction of arrival (DOA) to that of the desired signal. Therefore, in SDMA systems special emphasis must be put on the suppression of the multiuser interference aggravated by the effects of multipath fading.