Design And Realization Of Double Channels Wireless Sensor Network For Coal Mine Environment Multiparameter Monitoring

The reserves of coal are rich in our country and coal plays a very important role in the state resource system. But the natural conditions of coal mine in our country are complicated, what's more, the existed coal mine environment monitoring systems are behindhand, which presents in two aspects. The first one is inflexible wired transportation network limiting monitoring scope and the other one is most of the system can only monitoring one parameter. Both of them result in many production threats. Therefore, a double channels WSN (wireless sensor network) for coal mine environment multiparameter monitoring is proposed.Devices of the network include coordinator, main router, assistant router and end device. Coordinator is responsible for network foundation and managing the whole net; main router is responsible for maintaining the main communication channel and assistant router maintaining the spare one, and therefore the stability of communication can be guaranteed; each end device can monitoring multiparameter, which provides an all-around guarantee for safe production. In order to realize the monitoring functions of the network hardware is designed based on the universal structure of WSN and communication software is developed based on ZigBee protocol.In order to guarantee the formation of network topology, software is developed with respect to the flows of coordinator setting up network, main router joining network, assistant router joining network and end points joining network. Topology maintenance methods are proposed to manage the emergence of nodes leaving and joining. In order to reduce the power consumption 3 states are designed for the nodes: working, listening and sleeping.Data is collected and transported using periodic monitor mode or interruptive mode. In order to meet the need of multiple parameters monitoring hardware is configured and data format is designed. Routing mechanism is designed to make sure that data can be transported to the coordinator. Data based network management functions are developed and network capacity is analyzed in view of limitation of ZigBee protocol and way of data fusion.Collision avoidance methods and synchronization mechanism are designed for the purpose of guaranteeing the reliability of data transportation and stability of network.At last some experiments on network foundation, data collecting and transportation and network management are executed in the lab. The result ofexperiments indicated that topology of network can be set up; data can be bothcollected and transported successfully and expected management function performedwell.