基于区分服务的802.11 MAC层协议及其性能分析

针对无线ad hoc网络不能提供数据流优先级区分的问题,提出了一种基于IEEE 802.11 MAC协议的改进机制.该机制通过引入新的控制分组,使目的节点可以拒绝接收来自低优先级节点的数据,从而确保了高优先级数据业务的服务质量.还使用马尔科夫链模型对该区分服务机制进行了数学分析与评价,包括饱和吞吐量分析、分组丢弃概率分析和饱和时延分析.数学分析表明,该机制能够使高优先级数据流占用更多的带宽资源,并且降低了高优先级数据流的端到端平均时延和分组丢弃概率.

Analytical study of IEEE 802.11 MAC protocol based on differentiated services

Since IEEE802.11 ad hoc networks can not provide any priority scheme,a new scheme based on the 802.11 MAC(medium access control) protocol is proposed in this paper.The main idea is that,by introducing new types of control frames,receiving nodes may refuse to accept data of low-priority nodes.As a result,the QoS(quality of service) of high-priority data flow is effectively improved.On the other hand,a Markov chain model is used to analyze and evaluate the diffserv scheme mathematically,including saturation throughput,frame dropping probability and saturation delay.Our mathematical analyses demonstrate that the new mechanism can make the high-priority data flow obtain more bandwidth,and also reduce end-to-end delay and frame dropping probability.