An adaptive bandwidth request mechanism for QoS enhancement in WiMax real time communication

The IEEE 802.16 standard for broadband wireless metropolitan area network supports real time and non-real time services. It has a provision to design new packet-scheduling algorithms according to requirements to support quality of service (QoS) for real-time services. Till now published literature on WiMax states that, a service station (SS) requests for bandwidth to a base station (BS) for already arrived packets at SS from users. The BS then allocates the bandwidth to SS according to priority-based request. In this paper we propose a novel adaptive-bandwidth scheduling algorithm at SS, for real-time polling services (rtPS), wherein the SS predicts the arrival of rtPS packets prior to the arrival and requests the BS for bandwidth in advance. It has been observed by analytical model and simulation that, this adaptive algorithm provided better results with respect to the number of packets waiting at SS and average delay as compared to the widely accepted weighted scheduling algorithm