In this thesis work, the performance of uplink schedulers at the fixed WiMAX MAC layer has been considered. A new algorithm that adapts to changes, inherent in wireless environments, and heuristically optimizes the gains of uplink scheduling parameters has been designed. The strategy adopted by the algorithm is to do a trade-off between several network parameters that define the operations of the Base Stations (BS) and Subscriber Stations (SS) and is able to find the mean throughput at the MAC interface with each SS in all instances. This is in a bid to maximize the throughput of the uplink packets from the several disparate contending users of the BS at all times. The performance of this adaptive WiMAX Uplink algorithm has been evaluated using OPNET Modeler. Results indicate that the algorithm is primed to meet the demands of its users and improves QoS in case of various wireless network perturbations.