IEEE 80 2.15.4 MAC协议退避机制的改进  

Improved backoff mechanism for IEEE 802.15.4 MAC protocol

作　　者：乔冠华[1] 毛剑琳[1] 郭宁[1] 陈波[1] 戴宁[1] 张传龙[1] 

机构地区：[1]昆明理工大学信息工程与自动化学院,昆明650500

出　　处：《计算机应用》2013年第10期2723-2725,2749,共4页journal of Computer Applications

基　　金：国家自然科学基金资助项目(61163051);云南省应用基础研究基金资助项目(2009ZC050M)

摘　　要：考虑节点移动且数据传输率不断变化对网络性能的影响,针对IEEE802.15.4提出了一种网络负荷概率判断和指数加权滑动平均(PJNL_EWMA)的退避策略,在每次载波监听多路访问/冲突避免(CSMA/CA)算法开始时采用网络负荷概率判断思想判定当前网络状况,然后通过指数加权滑动平均方法动态地调整退避指数。通过NS2的仿真结果表明:与IEEE802.15.4标准协议算法及MBS+EWMA算法相比,PJNL_EWMA算法不仅提高了网络吞吐量,同时还减小了数据包的丢包率和碰撞概率,提高了网络性能。Concerning the impact on network performance of the mobile nodes and the constantly changing data transmission rate, the authors proposed a new backoff scheme for IEEE802.15. 4, which used Probability Judgment based on Network Load and Exponentially Weighted Moving Average （PJNL_EWMA） method. According to a real-time monitoring of current network status by probability judgment of network load, this method dynamically adjusted backoff exponent by EWMA when Carrier Sense Multiple Access with Collision Avoidance （CSMA/CA） began. Compared with the IEEE802. 15. 4 standard protocol and MBS （ Memorized Backoff Scheme） ＋ EWMA algorithm, the simulation experiments on NS2 platform show that the PJNL_EWMA algorithm not only improves the throughput of the network, but also reduces the packet loss rate and the collision ratio, significantly improving the network performance.

关 键 词：IEEE802 15 4 载波监听多路访问 冲突避免 指数加权滑动平均 吞吐量 碰撞概率 

分 类 号：TP393.07[自动化与计算机技术—计算机应用技术]