一种用于提高802.15.4网络性能的区分服务模型  

Service Differentiation Model for Performance Enhancement of 802.15.4 Sensor Networks

作　　者：蔡雅平[1] 白光伟[1] 

机构地区：[1]南京工业大学计算机科学与技术系,南京210009

出　　处：《计算机科学》2011年第7期61-65,共5页Computer Science

基　　金：国家自然科学基金项目(60673185;61073197);江苏省自然科学基金项目(BK2010548);教育部留学回国人员科研启动基金项目(教外司留[2007]1108号)资助

摘　　要：IEEE802.15.4作为低速率、低功耗的无线传感器网络标准,其媒体接入控制(MAC)协议的竞争接入时段(CAP)对所有数据帧和节点都采用相同的竞争参数,不能为某些需要服务区分的应用提供很好的服务。针对这一问题,提出了一种基于区分服务的改进IEEE802.15.4机制以支持高QoS要求。该机制的主要思想是根据服务质量要求(时延及吞吐量)为不同的数据流分配不同的优先级,对不同优先级数据设置不同的数据帧长度和竞争参数来达到区分服务的目的。与此同时提出一种区分服务的不饱和马尔科夫链模型来分析所提出的机制。该模型评估了采用此简单但有效的区分服务机制后两种优先级数据的信道接入概率、吞吐量、时延及能耗等性能。分析结果表明,此模型对区分服务起到了很好的效果。IEEE802.15.4 is one of the standards for a low rate,low power consumption wireless sensor networks.By assigning the same sets of contention access parameters for all data frames and nodes,the contention access period（CAP） of the slotted IEEE 802.15.4 medium access control（MAC） currently provides a priority-independent channel access functionality and no service differentiation.To solve this problem,this paper proposed a differentiated service mechanism to support high IEEE802.15.4 QoS requirements.The main idea of the mechanism is allowing different sets of access parameters and data frame lengths for different priority classes,we developed a Markov-chain-based analytical model of the CAP of the IEEE 802.15.4 MAC with service differentiation,under unsaturated traffic conditions.In particular,given two priority classes,our analytical model was used to evaluate the performance of a simple and effective service differentiation strategy,in terms of throughput,average frame service time,energy consumption,as well as access probability for each class.Our analysis results show that this model for differentiated services performs well.

关 键 词：IEEE802.15.4 竞争接入时段 马尔可夫链模型 区分服务 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]