Multi-Antenna SDMA in OFDM Radio Network Systems: Modeling and Evaluations

This paper presents and evaluates different multi-antenna deployments in an OFDM wireless system. Two downlink implementations, higher order sectorization (HOS) and downlink SDMA using fixed beams (FB), are considered. HOS with 3-, 6-, and 12-sector sites are compared with downlink FB SDMA in a 3-sector site where each sector is using up to four antennas. In the uplink we evaluate SDMA using multi-antenna MMSE receiver at base station. The simulation results indicate that in the downlink FB SDMA with four antennas per sector provides a cell throughput improvement of more than 100% compared to a 3-sector site equipped with a single antenna each. The gain can be further improved by using HOS at the expense of additional complexity. The uplink results show that SDMA allows to increase the throughput by up to a factor of two.