Deployment and design of multi-antenna wimax systems in a non-stationary interference environment

WiMax has already been adopted worldwide by operators attracted by promises of large throughput and coverage for broadband wireless access. However, towards the goal of an efficient deployment of the technology, a thorough analysis of its performance in presence of frequency reuse under realistic traffic conditions is mandatory. In particular, in both fixed and mobile WiMax applications, an important performance limiting factor is inter-cell interference, which has strong time-varying and non-stationary features. Two main solutions have been proposed for interference management at the physical layer of WiMax systems, namely, multi-antenna technology and random subcarrier permutation (as in the latest version of the standard, IEEE 802.16-2005). In this chapter, system deployment of multi-antenna base stations, and related design of signal processing algorithms for interference mitigation, are discussed. Extensive numerical results for realistic interference models show the advantages of the optimized multi-antenna deployment and design in combination with subcarrier permutation.