The IEEE 802.16 standard defines the specifications of the Worldwide Interoperability for Microwave Access (WiMAX) technology as a Broadband Wireless Access network. This type of networks supports multiservice traffic (data, voice and video) and guarantees the Quality of Service at the MAC layer level. However, the IEEE 802.16 standard specifies three QoS components that reside in the MAC layer such as scheduler and call admission control. Although, the IEEE 802.16 defined the function of each component but left the implementation open for vendors and operators. In this thesis, we aim to design two new scheduling algorithms that guarantee QoS in WiMAX network. The new algorithms will consider application traffic requirements, channel condition states and compliant with the standard. The first algorithm is Deadline maximum Signal to Interference Ratio (DmSIR) scheduling algorithm and it is a modified version from maximum Signal to Interference Ratio (mSIR) scheduling algorithm. The DmSIR scheduling algorithm makes scheduling decision based on two factors: the packets deadline and signal to noise ratio. The second algorithm which we named the Priority based Deficit Round Robin (PbDRR) solves the problem of long delay for non real-time traffic with low signal to noise ratio as well as giving priority to real-time traffic that approach to deadline. The PbDRR scheduling algorithm makes scheduling decision based on three factors: packets deadline, signal to noise ratio and backlog traffic. We used the NS2 network simulation to evaluate the performance of the new algorithms and three performance metrics are evaluated for this purpose. The simulation results for DmSIR shows enhancement in the performance compared to the mSIR scheduling algorithm but the non real-time traffic with low signal to noise ratio suffers from long delay. On the other hand, the simulation results for the PbDRR scheduling algorithm shows better performance than the DmSIR and Deficit Round Robin + Fragmentation (DRR+F) scheduling algorithms
