基于优先级的IEEE 802.16中VoIP弹性接纳控制算法  

Priority-based elastic admission control algorithm of VoIP in IEEE 802.16 system

作　　者：关艳峰[1] 胡爱群[1] 

机构地区：[1]东南大学信息安全研究中心,江苏南京210096

出　　处：《通信学报》2007年第10期23-31,共9页Journal on Communications

基　　金：国家高技术研究与发展计划("863"计划)基金资助项目(2005AA147040);江苏省网络与信息安全重点实验室基金资助项目(BM2003201)~~

摘　　要：通过分析IEEE 802.16关于VoIP(voice over IP)的传输规范和服务质量保证机制,指出了区分VoIP的优先级和VoIP要求弹性QoS的性质对VoIP接纳控制有着极其重要的意义,提出了VoIP接纳控制的弹性准则和优先级准则。在运用有效带宽理论确定了VoIP传输所需最小带宽的基础上,提出了基于优先级的弹性接纳控制算法,并以概率强度因子对算法进行了优化。该算法能够根据剩余资源动态地调整接纳强度和策略,对不同优先级的VoIP表现出不同的接纳特性,资源紧张时合理限制低优先级VoIP的接纳。为评价算法性能,通过Markov模型对建议算法的拒绝率进行分析,并在PMP(point-to-multipoint)模式下与新呼叫限制算法进行了对比仿真,结果表明本算法在表现出更高接纳能力的同时具有更低的新连接阻塞率和切换连接掉线率。By analyzing the transmission specifications and QoS （quality of service） guarantee mechanism about VoIP in the IEEE 802.16 system. The differentiated precedence for VoIP and the property of the elastic QoS requirements on VoIP were very important for its admission control was pointed out, and the elastics principle and priority principle were proposed. According to the effective bandwidth theory, the minimum bandwidth needed by transporting VoIP was attained and then a priority-based elastic admission control algorithm was presented, further more, it was improved in terms of the probability intensity factor. This algorithm can dynamically adjust the admission strengthen and strategy with the change of the left resources, have the different admission property for the VoIP with different priorities and constrain the admission of VoIP with low priority when the resource is insufficient. For evaluating the performance, the rejection probability was analyzed by Markov model and the simulation was done between the proposed algorithm and new call bounding al- gorithm in the point-to-multipoint mode, results show that the proposed algorithm can achieve lower new connection blocking probability and handoff connection dropping probability while more VoIP can be admitted.

关 键 词：无线城域网 接纳控制 VOIP 优先级 

分 类 号：TN925[电子电信—通信与信息系统]