Research On QoS Of Multimedia Services In IEEE802.16 Networks

Along with the rapid development of communication industry, the traditional wired access way can't satisfy people's needs. The new wireless access technology with its low cost, quick speed and good scalability become the new focus of the telecommunications industry. Meanwhile, business is becoming more and more diversification in the network.It is not only the original data transmission, various multimedia business impacting today's network, which let the people's life become more convenient and rich. The development trend of network, which make the Quality of Service (QoS)provided of various multimedia services becoming the concern, people pay more attention to the problem.IEEE802.16 standard is to cause as a kind of new wireless access technology in such an environment.And based on its WiMAX network has become the hot research field. IEEE802.16 standard contains the physical layer and Media Access Control layer (MAC), each of the different layers having the different function. The standard define four different types of business and their characteristic according to the different QoS. Therefore,it can provide different multimedia services for different requirements to meet the QoS of communication. But, in the QoS mechanism, standard is not given the specific scheduling strategy and method. Therefore, in order to solve this problem, this paper puts forward the cross layer mode based the topological structure of point-to-multipoint (PMP) and the specific scheduling strategy at the MAC layer. The scheme not only guarantees QoS of various multimedia business needs, but also the fairness in allocating bandwidth resources to all kinds of business in the network.This paper briefly introduces the IEEE802.16 d standard, analyzes the related technologies on QoS mechanism in the standard. For the problems in the standard, the paper analyzes and compares the models,the advantages and disadvantages of scheduling strategy proposed in current some solutions, based on those puts forward the improvement plan.In this scheme, we consider the network layer which is not mentioned in the IEEE802.16 standard, raise the across model.In this model,we fusion the QoS difference between IP business of the network layer and business of Standard at MAC layer by characteristic of each business.For the scheduling of MAC layer, we propose the improved scheme based on the traditional strict priority scheduling strategy. At the same time, this program also takes into account the channel quality factors and the bandwidth resource compensation policy.the resulting delay compensation strategy for bandwidth resources. Finally, we test in the NS2 simulation software,and analysis of experimental data and images obtained in order to prove that while ensuring the QoS multimedia services,,while the network is relatively equitable allocation of resources to the various business to ensure that a variety of multimedia resources for fairness.