Relay Node Deployment Algorithm Research For Coal Mine Gas Monitoring System Based On WSN

The development of mine things technology has pushed the application of WSN in coal mine gas monitoring system. The special environment of coal mine and short distance communication characteristic make some wireless nodes deployed in long tunnels cannot establish direct communication with Sink node. Therefore, it is necessary to deploy relay nodes in the network, in order to achieve reliable transmission of data. This thesis studied the relay node deployment schemes based on greed guidelines and put forward two improved mechanisms on the background of WSN mine gas monitoring system.This thesis analyzed the causes of mine gas accident and environmental characteristics of coal mine tunnel, then established a two-layer long strip network model based on WSN gas monitoring system. To make the model more fit the actual network, the communication capacity, the maximum number of child nodes, the maximum hops of communication paths and irreversible factor were utilized to constrain the network model.For the elongated feature of network, a long strip network relay node deployment algorithm based on greed guidelines was designed. It is divided into two stages,includes deploy relay nodes and connect sensor nodes. The number and location of relay nodes is determined based on the distance and communication radius of nodes.Then appropriate sensor nodes are selected based on four different greedy guidelines.The simulation results show that the relay node deployment algorithm based on nearest greedy criterion is suitable for wireless gas monitoring system.Since the initial network based on nearest greedy criterion is single connected,the reliability is low and the relay node which closer to the gateway has heavier load,in addition this algorithm does not consider the network can increase sensor nodes at any time. For the first question, a fault tolerant load balancing mechanism was put forward, which can balance the load of relay nodes by deploying a small number of redundant nodes. For the second question, a network expansion program was presented, which can connect the added sensor nodes without changing the topology of initial network. Finally, simulation experiments testify the feasibility of the above two improved mechanisms.