Impact of Multipath Fading on the Fairness of the WiMAX System

In the WiMAX system, the use of the OFDMA technique at the physical layer makes it possible to dynamically select, for each subchannel, the user that can achieve the maximum throughput. This goal can be obtained at the expense of a bad fairness, which can severely penalize some users. Therefore, a proper scheduler is needed at the base station for the assignment of radio resources to users striking a tradeoff between throughput and fairness. This topic is investigated in this paper by considering a family of schedulers based on a utility function characterized by a single parameter. The time-varying channel is modeled according to a Finite State Markov Chain (FSMC). Simulation results illustrate the performance in terms of throughput and fairness in a WiMAX environment in the presence of multipath fading. Our study shows which schedulers strike a balance between throughput and fairness.