Study On Strategies Of Base Station Allocation And Handoff Oriented To Underground Unmanned Locomotive System

Minerals such as coal and metal are the important and indispensable resources for the national development,and most of them are obtained by the way of underground mining.The state has attached great importance on the underground safety operation for many years,but up to now the mine accidents still happen occasionally,which has caused great damage to the people and the country.In that context,the application research on the underground unmanned locomotive system can reduce accidents and improve the working efficiency of the mining area.The underground network which mainly includes the upper wired optical fiber ring and the lower wireless mobile access network is used for communication connection in the system,in which how to ensure the fluency operation of the lower wireless communication network is very important to the performance of the unmanned locomotive system.Based on this,this thesis studies the base station frequency point selection and the optimization problem of unmanned locomotive communication handoff.The finished work as follows:(1)From the perspective of how to reduce the communication interference between the wayside base stations,a frequency allocation strategy based on weighted conflict model is presented in this paper.First of all,through the analysis of the interference factor,the actual communication interference model of the underground base station is derived;then,based on the analysis of the relationship between the distance of the base station and the frequency point,the model optimization problem is transformed into the constraint satisfaction problem;finally,the overlapping frequency points allocation algorithm is proposed to obtain the optimal frequency allocation vector and the corresponding minimum interference estimation.The simulation results show that the proposed method can minimize the interference between the base stations and has better adaptability in different communication frequency bands.(2)From the perspective of how to get the maximum communication handoff revenue,an underground wireless base station handoff strategy based on Markov Decision Process(MDP)is proposed in this paper.Firstly,it takes the handoff delay and available bandwidth of each base station as handoff criterion in the established underground wireless communication model;secondly,the utility function is defined by the communication revenue from the handoff criterion and the signaling overhead;finally,the optimal handoff strategy based on MDP could be got by using the bellman equations and the loop iteration method.The simulation results show that the expected total utility of the proposed handoff strategy is superior to the high bandwidth handoff scheme and the unilateral handoff scheme.