摘要
无线传感器网络(WSN)的MAC协议主要采用基于CSMA/CA的DCF机制,上述协议的能源效率随网络中竞争节点个数和负载的增加而迅速恶化。研究发现,CSMA/CA可以认为是1-坚持CSMA和p-坚持CSMA的混合体[3]。本文提出了一种状态检测与竞争节点个数的自适应优化机制,ABM(AdaptiveBackoffMechanism),同时引入了信号流图模型这种新的方法来进行数学建模。根据相关数学模型的分析,p与系统参数存在着一定的数学关系,竞争节点个数和负载的变化都会引起p的改变,因此通过p的变化对相关参数进行动态调整,从而有效地改善了协议的整体性能。同时给出了相关模型和计算的详细说明,最后实验仿真,新的方法能够根据竞争节点个数和负载的变化对系统性能进行整体优化,在能量效率方面明显优于标准的CSMA/CA的DCF机制。
The number of competing stations and the offered load of all stations have great influence on the performance of wireless sensor networks （WSN） MAC protocol based on the distributed coordination function （DCF）, which utilizes carrier sense multiple access with collision avoidance （CSMA/CA）. In the research, CSMA/CA is considered as a hybrid protocol of slotted one-persistent CSMA and p-persistent CSMA [3]. In this paper, an adaptive optimization mechanism, ABM （Adaptive Backoff Mechanism） which is based on the condition detection, the offered load and the competing station number are proposed. Moreover, a new mathematic method, Signal-Flow Graph Model are used to modeling. Under mathematical model analysis the p value has relation to protocol parameters. Therefore, the protocol can be improved by tuning related parameters via the change of p value. Later on, the detailed system model and performance evaluation for the new mechanism are given. The elaborate numerical results show that the mechanism could achieve much higher energy efficiency than the standard CSMA/CA DCF in almost all the different competing stations numbers and offered load.
出处
《传感器世界》
2006年第9期34-38,共5页
Sensor World
基金
重庆市科委自然科学基金项目资助(CSTC
2005BB2198)
