基于IEEE802.15.4退避算法的改进机制  

Improved back off algorithm in slotted CSMA/CA for IEEE 802.15.4

作　　者：吉诚[1] 徐友云[1] 郑宝玉[1] 

机构地区：[1]上海交通大学无线通信研究所,上海200240

出　　处：《信息技术》2008年第8期8-12,共5页Information Technology

基　　金：上海市科学技术委员会资助项目(05DZ22102)

摘　　要：IEEE802.15.4是供低速率、低功耗和低成本设备使用的短距离无线通信的协议,定义了低速无线个域网(LR-WPANs)的MAC层和物理层规范。由于在例如无线体域网(WBAN)应用中,能量消耗是备受关注的问题,因此提出了一种基于时槽机制的CSMA/CA过程中改进的退避算法,在每次CSMA/CA开始时根据过去的传输状况动态地调整竞争窗口的最小值。通过NS-2进行仿真,实验结果表明这样的改进方案在业务负载比较高或者包的大小比较小的时候可以减少数据包碰撞概率和重传概率,从而可以减少功耗并且提高吞吐量性能。IEEE 802.15.4 defines MAC and PHY specifications for low-rate wireless personal area networks （LR-WPANs）, which targets wireless networking among low-rate, low-power and lowcost devices for short range telecommunication. This paper proposes an improved back off algorithm in slotted CSMA/CA, to dynamically change the minimum contention window each time CSMA/CA begins, according to the past transmission condition, qhe main contribution in this work is the low power consumption considered particularly in the applications such as medical sensor body area networking. The proposed scheme can decrease the collision ratio and the retransmission ratio, resultin significant power saving and throughput improvement when the traffic load is high or the packet size is small, Which are verified through extensive simulations.

关 键 词：IEEE 802.15.4 CSMA/CA 功耗 吞吐量 

分 类 号：TN915[电子电信—通信与信息系统]