An efficient uplink scheduling at subscriber station for VoIP services in WiMAX networks

Existing uplink scheduling schemes at subscriber station (SS) in WiMAX suffer from problems like waste of resources and greater access delay for VoIP services. We propose an efficient uplink scheduling scheme to solve above mentioned problems. The SS uses two reserved bits of generic MAC header of IEEE 802.16d to record the voice status of current time unit and informs the base station (BS) without additional overhead. BS provisions the required bandwidth according to the voice status. The simple uplink bandwidth request method is demonstrated to decrease the access delay and increase the system throughput when the network size grows. Simulation results also have shown that the proposed scheme is effective at reducing the required uplink bandwidth while achieve the same throughput made by other schemes.