基于预警优先级的ZigBee传感网络MAC层退避算法

针对无线传感器网络中有预警信息的高优先级数据包需要尽快传输，且IEEE 802.15.4协议本身不支持任何优先级传输机制的情况，提出了一种基于预警优先级的非时隙CSMA/CA自适应调整阶梯退避算法，并建立了离散时间马尔可夫分析模型，比较分析了网络中不同优先级节点的信道接入概率、网络吞吐量和传输延时，仿真结果表明，本文改进的自适应调整阶梯退避机制对提高无线传感器网络中高优先级数据包的实时传输性能具有积极的作用。

The Early-warning Priority-based ZigBee Sensor Network MAC Layer

The early warning information of high priority packets in wireless sensor network needs to be transmitted quickly. And IEEE 802.15.4 protocol doesn''t sustain any priority transmission mechanism. Based on this situation, we propose an unslotted CSMA/CA adaptive adjustment of step backoff algorithm based on early warning priority, and model Discrete time Markov analysis. Meanwhile, we compare and analyse the channel access probability, network throughput and transmission delay for the different priority nodes in network. Adaptive adjustment of step backoff probability mechanism improved in this paper has positive effects on improving real time transmission performance of high priority packets in wireless network.