Residential Building Gas Leak Monitoring Via Opportunistic Routing

In recent years,explosion caused by gas leak takes place frequently.The explosion will bring significant economic losses,a lot of injures and even death,and bad society effect.Using sensor networks can monitor leakage in real time and give a timely alarm.In this paper,we study the reliable routing protocol with low latency for the sensor network system.A large number of measured data show that,packet losses are frequent due to the building structure and cross technology,and there exists link correlation.Meanwhile the neighborhood size is small.Therefore,considering these characteristics,we propose ROAP(Reliable Opportunistic Acquisition Protocol),a novel hop-tree based opportunistic forwarding mechanism.This protocol uses the idea of opportunistic forwarding to manage and select the forwarding nodes,so that each forwarding node has the opportunity to forward packets,thus improving the reliability of the transmission under unreliable links.Forwarding nodes are sorted according to Expected Transmission Cost(ETC).Nodes with high priority forward packets first,where the expected transmission cost is calculated considering link correlation in order to improve the accuracy of calculation.The performance evaluation of ROAP was carried out by experiment and simulation.Experiments were carried out on our test-bed with 20 nodes,and all the functions of ROAP were verified.Simulation was carried out on TinyOS platform with large scale network nodes.The results show that,compared with well-known protocol CTP,the shortest path algorithm and directed flooding protocol,ROAP meets the needs of system requirements on low latency and reliability,and is highly robust to packet loss.