Research Of Mine Monitoring System Based On Wired/Wireless Sensor Network

Mine monitoring system is the significant guarantee of safety production in coal mine. The traditional monitoring system is mainly based on cable communication facilities which causes inflexible access of sensor nodes, and narrow monitoring scope. With the rapid development of wireless sensor network technology, environment monitoring has been one of the most essential application taking advantage of its low cost, low consumption and easy configuration.However, there would be some great challenges when deploying large-scale wireless sensor network, especially network lifetime and reliability. Some nodes may suffer heavy traffic, such as coordinator and gateway, whose consumption is much more than others, which leads to a short lifetime of the whole network. Besides that, wireless communication may be in congestion, even break on account of complicated environment of mine.This paper proposes a brand-new design scheme of hybrid sensor network aiming at the problems as described above. Back bone cable system, connected with wired nodes, is based on existed coaxial line, deploying wireless sensor nodes around them, which accessing cable by wireless communication. Both of those two channel use the same standard in lower layers, that is IEEE 802.15.4. On one hand, it guarantees the reliability of bone network and extensibility of sensor network. On the other hand, it needn’t protocol conversion to conserve construction cost.The hybrid sensor network is studied deeply, architecture based on data aggregation and system model of different functional nodes are presented. And we design flexible working modes including periodical report, base station query and emergecy, according to actual demand. Furthermore, the paper proposes a scheme of the hybrid network of wireless contention access and wired time division schedule, and elaborate work flow of the network comprehensively, involving each part of the network and core algorithm, such as slots periodical assignment, beacon synchronization, data aggregation, commnunication in intra-cluster and inter-cluster.At last, the design scheme is validated by modeling and simulation. The result shows that, the scheme can reduce communication confliction, and guarantee network throughput. It can satisfy requirement of mine environment monitoring theoretically.