SCHEDULING ALGORITHM FOR OPTIMIZED BANDWIDTH USAGE IN WIMAX NETWORKS

Abstract

Interest in broadband wireless access (BWA) has been growing due to increased user mobility and the need for data access at all times. IEEE 802.16e based WiMAX -networks promise the best available quality of experience for mobile data service users. Unlike wireless LANs, WiMAX networks incorporate several quality of service (QoS) mechanisms at the Media Access Control (MAC) level for guaranteed services for data, voice and video. The problem of assuring QoS is basically that of how to allocate available resources among users in order to meet the QoS criteria such as delay, jitter and throughput requirements. IEEE standard does not include a standard scheduling mechanism and leaves it for implementer differentiation. Scheduling is, therefore, of special interest to all WiMAX equipment makers and service providers. The goals of scheduling are to achieve the optimal usage of resources, to assure the QoS guarantees and to maximize throughput while ensuring low algorithm complexity. The work in this dissertation is focused towards exploring the key issues and design factors to be considered for scheduler designers and. to propose a novel approach for the optimized usage of the band width. We propose a novel Downlink Slot Reservation (DLSR) scheduling algorithm based of a new slot reservation concept for the Base Station of the WiMAX. This approach optimizes the usage of the bandwidth in the WiMAX networks by taking accurate decisions of how the bandwidth should be allocated . to various types of connections. The simulation results show that by using proposed DLSR approach the throughput of the non real time connections. increased to 55% which comes at the cost of some increase in the delay of real time connections. The approach is also able to maintain the QoS requirement of the real time connections as this increase in delay is within limits. Along with that the algorithm is also computationally less comple