Teletraffic analysis of SDMA-systems with inhomogeneous MS location distribution and mobility

One of the most widely used buzzwords in mobile communications of the recent years is Space Division Multiple Access (SDMA). The introduction of an additional space domain multiple access component is likely to boost system capacity, due to the spatial reuse of physical channels within one cell. While early approaches of SDMA system modelling show capacity to be gained in the order of 300 to 400%, there remains some more in depth system analysis to be done, as inhomogeneities in the user distribution are expected to likely cause dramatic drops in the additional capacity gained by SDMA. The spatial distribution of terminals directly influences the number of channels to be gained by spatial multiplexing. Therefore, it is not until detailed models for user distribution, user mobility and the traffic load generated by users are combined with a model of the SDMA radio subsystem, that realistic approximations for these capacity gains are possible. In this paper, we discuss the issues in modelling and simulation of SDMA systems. We present an approach for integrated SDMA system modelling, discuss analytic teletraffic dimensioning methods for macro- and microcellular environments and their relevance to SDMA systems, and present some early simulation results.