Power control optimization in LMDS networks operating above 20GHz through Fuzzy Inference Systems

Local Multipoint Distribution Service (LMDS) systems operate at frequency bands above 20GHz. Code division multiple access (CDMA) schemes have been proposed for this technology. LMDS networks at millimeter wave bands are susceptible to tropospheric propagation phenomena and their Quality of Service (QoS) performance mainly suffers from rain attenuation and inter-cell interference. In this paper we propose a new Fuzzy Inference System (FIS) for the formulation of a downlink power control scheme, according to which the transmitted power is adjusted based on the output of the FIS. Furthermore, the power allocation is site-dependent because it depends on the long term statistical distribution of rainfall rate which influences the rain attenuation. Finally, we present simulations and comparison results of the proposed FIS downlink power control method and classic power control in terms of outage probability.