Research On Key Technologies Of Post-disaster Reconstruction Of Coal Mine Internet Of Things For Emergency Communication

Coal mine Internet of Things(IoT)has played an important role in coal mine safety production.Coal mining process is often affected by disasters such as gas explosion,roof fall and rock burst.Disaster accidents often cause the destruction of some nodes in the coal mine IoT,which in turn leads to the destruction of the original network topology and the interruption of data communication.The post-disaster reconstruction of coal mine IoT is of great significance for improving the emergency response speed and emergency rescue effect of disaster accidents.Based on the coal mine IoT,this paper studies the key technologies such as the discovery of surviving nodes,network reconstruction method and routing optimization algorithm involved in the post-disaster reconstruction of coal mine IoT.The specific contents and achievements are as follows:(1)Aiming at the problem of resource interference between the cellular users and the surviving nodes as well as the resource competition between the surviving nodes after the disaster of coal mine IoT,a resource allocation method suitable for the discovery of the surviving nodes after the disaster of coal mine IoT was designed.On this basis,an autonomous discovery mechanism based on random back-off for surviving nodes after the coal mine IoT disaster was proposed.This proposed mechanism realizes the discovery of the surviving nodes through the two processes of dedicated discovery resources selection and beacon's Signal to Interference plus Noise Ratio(SINR)decoding.Simulation results show that the proposed mechanism can effectively improve the average discovery number of the surviving nodes.(2)Aiming at the problem that the limited and heterogeneous residual energy of the surviving nodes in the post-disaster reconstruction network for coal mines IoT,an Energy-balanced Adaptive Clustering(EAC)routing algorithm is proposed.EAC algorithm designs the cluster head election threshold function of the post-disaster reconstruction network based on the residual energy factor,distance factor and density factor of the surviving nodes,and the weight coefficients of the three factors are calculated by Analytic Hierarchy Process(AHP),then the cluster head election is carried out by calculating the cluster head election threshold function.The member nodes select the cluster head with the smallest communication cost function to join according to its distance from the alternative cluster head and the remaining energy of the alternative cluster head to form a cluster structure.Simulation results show that,compared with the classical clustering routing algorithm,the EAC algorithm can better adapt to the energy heterogeneity of the surviving nodes,effectively reduce the energy consumption of the surviving nodes,and significantly prolong the survival time of the reconstruction network.(3)Aiming at the problem of unbalanced energy consumption between clusters when EAC algorithm is used in the post-disaster banded clustering reconstruction network of coal mine IoT,an Energy-balanced Uneven Clustering Multi-hop(EUCM)routing algorithm is proposed.EUCM algorithm introduces the mechanism of candidate cluster head selection to avoid surviving nodes with insufficient energy and poor location from participating in the cluster head election.Candidate cluster heads form different scale competition ranges according to their residual energy and geographic location,and compete with neighbor candidate cluster heads for official cluster heads through a competitive back-off mechanism to form uneven clustering.The single hop or multi-hop hybrid communication mode is adopted by cluster head according to the distance between the cluster head and the gateway of the IoT,and the next hop routing comprehensively takes into consideration the remaining energy of the alternative cluster head,the number of member nodes contained in the alternative cluster head and the energy consumption of communication between clusters.Simulation results show that,compared with the EAC algorithm,the EUCM algorithm effectively balances the overall energy consumption of the reconstruction network,significantly extends the survival time of the reconstruction network,and improves the data transmission of the reconstruction network.The above work provides a certain theoretical basis and solution ideas for the effective reconstruction of the coal mine IoT after the disaster.