嵌入式无线传感器网络节点设计与通信研究

Study of embedded wireless sensor node design and communicating realization

针对无线传感器网络技术的发展趋势,采用32位ARM核微控制器LPC2138设计并制作了一款无线传感器网络节点,节点的通信单元采用了射频芯片IA4420.在解决了SPI接口时序判别和连接方式等问题后,给出了IA4420的一种基于外部中断的数据收/发方法,实现了节点间的通信功能.比较了IA4420与符合IEEE802.15.4标准的射频芯片CC2420,IA4420易于设计并且不受现有通信标准的制约,通信协议可由用户自行定义,便于实际检验通信协议的优劣.进行了基于射频芯片IA4420接收信号强度指示实验,实验结果显示IA4420的RSSI功能可比较可靠地用于连接质量指示,但用于定位是不可靠的.

A novel wireless sensor node is developed using 32 bits microcontroller LPC2138 as processing unit, considering technology direction of wireless sensor networks. Radio frequency chip IA4420 and CC2420 compatible with IEEE802.15.4 are introduced. Compared with CC2420, IA4420 is not restricted to any communication standard which gives users more space to explore completely new protocol; application circuit design of IA4420 is simpler than CC2420, even any other radio chip, so it is chosen as communication unit of the sensor node. After solving SPI （serial peripheric interface） timing issue and connection between LPC2138 and IA4420, the method of transmitting and receiving data through IA4420 is presented in detail. Experiments for evaluati strength indicator） provided by IA4420 are performed. Results indicate that can be used as good link quality estimator, but is not good for node location. ng R RSSI （received signal SSI output of IA4420