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IEEE 802.15.4 protocol aims to develop a low-cost, low-power , low complexity , with the ability to self- networking wireless personal area network standards , and to develop a physical layer and media access layer specification , is wireless sensor networks standard best choice . In-depth study protocol , and optimized to make it more suitable for wireless sensor networks is currently a hot research IEEE 802.15.4 protocol has great significance . Based on the analysis protocol , based on the study protocol throughput, success rate , with an average delay of several performance algorithms and introduces priorities are optimized . Firstly, a comprehensive analysis of the IEEE 802.15.4 MAC layer protocol , in-depth study of the impact on the protocol performance exist various factors . Then using OPNET simulation software , the establishment of a network based on a star topology network simulation model, complete and accurate implementation of the protocol CSMA / CA mechanism . And the use of the simulation model for the IEEE 802.15.4 MAC protocol for a large number of simulations to study the different scale networks of different network load , BO, BE, CW network parameters such as throughput, success rate , with an average delay of algorithms for rational setting network parameters to provide a reference . On this basis , the introduction of priority ideas for the network packets of different priorities , providing different channel competitive strategy, improve the network in real time , optimizing the performance of the protocol . And using Markov chain theory , the establishment of a saturated channel priority-based thinking IEEE 802.15.4CSMA/CA mathematical model to analyze the network through a priority for the difference between the two formats and set different packet protocol parameters , real-time impact on the node . Simulation results show that the introduction of priority thoughts, can significantly improve the signal -priority real-time, while the performance of the network has little effect on the overall performance . Since no hardware modifications , so thinking of introducing priority optimization of universal significance .
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