| Wireless broadband access technologies have become the focus problem alongwith the increasing demand for bandwidth. IEEE 802 committee constituted 802.16workgroup to institute broadband wireless access standard, providing the last-mileconnection to Internet service. WiMAX (World Interoperability for MicrowaveAccess) is one kind of wireless broadband access technologies, based on IEEE 802.16standard, also named after WMAN (Wireless Metropolitan Area Networks), which isa new air interface standard.This paper focuses on packet scheduling algorithms on MAC (media accesscontrol) layer of WiMAX, in which there are two modes: PMP mode and Mesh mode.Therefore, packet scheduling algorithms are studied in these two modes.Firstly, in PMP mode, throughput, fairness and drop rate performances indownlink scheduling of IEEE 802.16e based TDD-OFDMA sectored cellularnetworks are evaluated. The performances mentioned above are analyzed withdifferent scheduling algorithms and frequency reuse schemes. Considered schedulingalgorithms are RR, Max C/I, PF and DPF which is proposed in this paper. The3-sectored with the same frequency and 3-sectored with different frequencies plansare compared in terms of throughput fairness and drop rate, which assist indetermining the choice of a scheduling and frequency reuse plan.In addition, the MAC protocol of IEEE 802.16-2004 standard specifiesscheduling mechanisms about Mesh mode in detail, while its channel resourcescheduling algorithms are not specified detailedly. This paper proposes two slotscheduling algorithms based on priority to achieve QoS on MAC layer. Simulationsare conducted to study average delay, request reject rate, minislot utilization and droprate based on proposed algorithm. The simulation results show that proposedalgorithms achieve QoS of different services.Last but not least, a conclusion of this paper is given and several aspects offurther research are presented respectively based on PMP mode and Mesh mode. |
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