The Research Of Cross-Layer Approach For Wsn Optimization Strategy Based On Ieee802.15.4

With the progress in sensor technology, sensors become smaller, intelligent and cheaper. As results, wireless sensor networks have been widely applied in many scenarios. For example, wireless sensor networks can be applied to natural disaster warning, biomedical health monitoring, hazardous environment exploration and other scenarios, and have been the research focus. IEEE802.15.4standard, the short-range wireless communication standard is considered to be most suitable for wireless sensor networks implementation, and has been widely applied to various applications. But the increasingly diverse applications make slots IEEE802.15.4MAC protocol CSMA/CA algorithm default parameter configuration cannot be applied to all applications properly, so the algorithm performance analysis and improvement strategy is key issues to expand its scope of application. This paper analyze slot CSMA/CA algorithm with theoretical model, and study the slot CSMA/CA algorithm improvement strategy through cross-layer optimization method. The work of this paper are as follows:1) For the diverse nature of the network load in wireless sensor network applications, this paper considers the collision, ACK mechanism, retransmission mechanism and traffic load to improve the analysis model of Slot CSMA/CA algorithm. This paper analyzes affect of the slot CSMA/CA algorithm parameters on the reliability of the network with the modified Markov model.2) For the complexity of wireless environment, this paper studies a kind of improvement strategy for slots CSMA/CA algorithm. The improved retransmission strategy takes into account the collision, the hidden terminal, fading of environmental factors. Simulation results show that the improved retransmission strategies can improve system reliability, reduce latency and energy consumption.3) For the WSN which does not make sure the network load when it is established, an improvement of time slot CSMA/CA algorithm parameter configuration strategy is proposed based on the multi-objective optimization theory and cross-layer approach,. According to the simulation with NS-2,the performances of the improved strategy in the packet delivery ratio, energy efficiency have been improved.