DPRP: Dual-path relay placement in WiMAX mesh networks

IEEE 802.16j has introduced the concept of WiMAX mesh network model, which adds a special type of nodes called Relay Stations (RSs) for Subscriber Stations (SSs). With the help of RSs, a WiMAX mesh network is able to provide larger wireless coverage, higher network capacity and Non-Line-OfSight (NLOS) communications. In this paper, we propose a novel strategy which named Dual-Path Relay Placement (DPRP) to improve the efficiency of relay station placement in WiMAX mesh networks. DPRP is a more reliable model that takes users Spectrum Efficiency into account and thus can achieve efficient spatial reuse by two independent parallel transmission paths.If the distance between Subscriber Station and Base Station is constant, the SS´s Spectrum Efficiency has a big influence on the number of relays required by the SS. For a given attenuation coefficient, DPRP needs less RSs than Single-Path Relay Placement (SPRP) when the SS´s Spectrum Efficiency exceeds a certain threshold. The analysis proves that the higher the Spectrum Efficiency is, the greater the difference is between the relay´s number of two models. If the new model is integrated with the SPRP model, the total number of RSs required per cell will decrease a lot.