基于ZigBee环境监控系统的MAC协议研究

摘要

As the periodicity of data transmission, small data and long intervals in environmental pollution monitoring system, an improved IEEE802. 15. 4 MAC layer specification, emMAC . Is proposed. It use the reserved bits and keep the size and format unchanged, subdivide the GTS slot into up to 112 small slots, each node can be assigned a slot for CFP access. Warning mechanism is added for enhancing the QoS. emMAC keep the compatibility with IEEE802. 15. 4. The performance of emMAC is analysed, simulations show that the protocol can effectively avoid the collision, reduce energy consumption and prolong the network life.%针对环境污染监控系统数据量小、时间间隔长、周期性等缺点,改进IEEE 802.15.4 MAC层规范,提出适合环境监测系统的协议emMAC,协议使用MAC层帧的保留位,保持帧长和格式不变,将GTS时隙进行再细分,最多可分为112个时隙,可为每个节点分配一个时隙进行CFP访问,并为提高QoS加入预警发送机制.emMAC保持了与IEEE802.15.4的兼容,通过使用omnet++4 1分析与仿真表明,协议有效的避免了信道冲撞,减少能耗,延长了网络寿命,性能优于802.15.4协议.