Chain-Type Wireless Underground Mine Sensor Networks for Gas Monitoring

To enhance the reliability of gas monitoring system in coal mine. An energy efficient and QoS supported chaintype wireless sensor networks for gas monitoring in coal mine is studied in this paper. Chain-type wireless underground mine sensor networks is introduced firstly. Then detailed energy efficient schemes including node scheduling and data fusion are proposed, and QoS supporting schemes including sensing QoS and transmission QoS are brought forward and analyzed respectively. Finally, interrelated performances of the schemes are studied by MatLab Monte-Carlo simulation and OPNET network simulation. The results show that, firstly, MAC protocol without ACK scheme shows around 3 times better performances in chain-type networks. Secondly, node scheduling scheme brings great system reliability, however the high scheduling frequency also increase the system energy cost. The system energy cost with data fusion and merger schemes is only 1/8 energy cost of system without them, especially under high scheduling frequency. Thirdly, Comparing to the random node deployment strategy, the QoS supported strategy proposed in this paper can prolong the life by two times. The optimal copies assignment strategy proposed in this paper improves the reaching probability two times higher than random strategy.