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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 MAC protocol of Wireless Sensor Network (WSN) mainly adopts CSMA / CA based DCF mechanism. The energy efficiency of the above protocol deteriorates rapidly with the increase of the number of nodes and load in the network. The study found that CSMA / CA can be considered as a 1-adherence to the mixture of CSMA and p-adherent CSMA [3]. In this paper, an adaptive optimization mechanism for state detection and number of competing nodes is proposed. ABM (Adaptive Backoff Mechanism) is introduced. At the same time, a new method of signal flow graph model is introduced for mathematical modeling. According to the analysis of relevant mathematical models, there is a certain mathematical relationship between p and system parameters. The number of competing nodes and the change of load will cause the change of p. Therefore, the relevant parameters are dynamically adjusted through the change of p, thus effectively improving the protocol The overall performance. At the same time, a detailed description of the relevant models and calculations is given. The final experimental simulation shows that the new method can optimize the overall system performance according to the number of competing nodes and the load changes, which is obviously better than that of the standard CSMA / CA DCF mechanism.