Impact of Mobility on Physical and MAC Layer Algorithms Performance in Wimax System

The WiMAX 802.16e system is intended to support applications with challenging quality of service constraints in heterogeneous scenarios where both low and high mobility users are simultaneously active. However, the fast and deep channel fluctuations that are leveraged in rich scattering environments (i.e., urban scenarios) affect the performance of e.g., channel estimation, link adaptation and scheduling algorithms. Therefore, the physical and MAC layer algorithms need to be designed in order to support both low and high mobility users. Herein, the impact of users mobility on the design and the performance of the physical and MAC layers of a WiMAX base station is assessed, and suitable solutions for the channel estimation, dynamic link adaptation and scheduling algorithms are provided. Simulation results provide indications on the achievable maximum cell load for different mobility and QoS profiles. The optimal trade-off between the PUSC and AMC permutations is also numerically investigated.