The Optimization Study On IEEE802.16 QoS Scheduling And Handover Mechanism

Broadband wireless access technology in the communication field today has a wide application prospect and great potential for development. IEEE802.16 access technology is an emerging standard which can provide QoS guarantee in telecom-level. Its QoS guarantee mainly depends on its MAC layer's technical support. IEEE802.16 provides a mechanism of QoS interfaces for different business to provide the appropriate QoS guarantee,but does not propose specific QoS implementation.The paper studies on the QoS architecture, scheduling algorithm and handover mechanism in depth on basis of overviewing 802.16 MAC layer agreement. This paper proposed the AMC scheme for IEEE802.16d system against the OFDM physical layer standard of IEEE802.16d. In addition, this issue also introduces WiMAX mobile networking research and handover simulation against the 802.16e standard for mobility support. Our contribution consists of the addition of the QoS classes as well as the management of the QoS requirements,unicast and contention request opportunities mechanisms,and scheduling algorithms for the UGS, rtPS and BE QoS classes. Meanwhile,basing on the detailed analysis of the two layer handover process of a node moving in the mobile WiMAX network,the topic discusses how the value of lgd_factor which controls the Link Going Down trigger to touch off the process of scanning influences data throughput and packet delay.The programming language is C++ and Otcl, the data analysis tool is the Gnuplot tool and the Gawk language.Simulation results provide observations about the throughput and mean sojourn time values. Simulation results show that our QoS architecture and scheduling algorithm are in accordance with the specication of the QoS classes defined in the IEEE802.16 standard and can provide an effective and reliable QoS guarantee for the 802.16 wireless broadband access system. The simulation results also prove that the scanning process is triggered earlier, the handover's influence to the performance of traffic is lower while a node performs two layer handover in moblie WiMAX network. Finally the simulation tests the performance of data throughput under different MCS,and makes an earlier proof to the design of AMC.