| IEEE802.15.4is the present wireless network technology with high speeddevelopment, low rate, and a wide range of applications produced by demand the lowspeed of a domain nets standard wireless communication protocol. It becomes theadvantage of network organization of wireless sensor network communication’s firstchoice because of its low cost, low power consumption, low complexity. According tothe actual demand to improve and optimize, further explore become a instantlywireless sensor network research hotspot. This article in view of the actual demand ofwireless sensor network contains special important information will need to get a highpriority packets priority transmission the reality of the situation, and the standard ofthe IEEE802.15.4not formulate relevant priority distinguish mechanism, and proposesa standard IEEE802.15.4CSMA/CA algorithm was used to optimize the improvedalgorithm. The algorithm for CSMA/CA mechanism import the priority of thedistinction between ideas, optimized the transmission mode of the network.First, the article Analysis the principle of wireless sensor network and thestandard IEEE802.15.4MAC layer protocols theory. Especially focuses on theanalysis of Slotted CSMA/CA algorithm mechanism, include3key parameters:NB,CW and BE. Then according to the defects that the standard CSMA/CA algorithmcan’t distinguish the nodes’ priority, come up with a Priority-based slotted CSMA/CAalgorithm, and establish the Markov chain model of this improved-mechanism. Thenwe use the OMNeT++simulation tool to check the effect of the mechanism, improvedit’s superiority.After introduce the improved algorithm, consider to reduce the node’s powerconsumption and extend the network’s life cycle, we introduce a node sleep in advancemechanism. Then we create corresponding node state switch model to analysis themechanism, and use OMNeT++to make sure that the mechanism have the real affect toreduce the node’s power consumption. |
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