Channel allocation in SDMA cellular systems

Spatial Division Multiple Access (SDMA) is recognized as a promising technique for improving capacity in future cellular systems, by exploiting the spatial filtering capability of adaptive antennas. In SDMA systems, in-cell users can share the same channel, making the channel allocation strategy play an important role in the system performance. In this paper, we analyze by simulation different strategies for channel allocation in cellular systems employing adaptive antennas and SDMA technique. Results show that high performance in SDMA systems is achieved by balancing channel reuse among cells with channel reuse within cells. Attempts to maximize channel reuse within cells may increase excessively co-channel interference, limiting capacity. Results also show that, while carried traffic is not severely affected by high level of user mobility, other performance parameters, such as the number of channel reassignment requests, are strongly affected by user mobility.