Research On Adaptive MAC Protocols Of Wireless Sensor Network In Mine Emergency Communication

Coal mining safety has been the focus of government.Mining environment is complex and with special geographical conditions.It has become a heated spot of academic attention that applying the wireless sensor network(WSN)to the mining monitoring and information transmission,with the characteristic of rapid expansion,self-organization and so on.The study of employing WSN network in mining research has made some achievement.But none has ever linked the design of WSN MAC with emergency communication.This paper aims at the special application environment,selecting the research content from three aspects:(1)In normal operation mode,the layout of WSN node changes with the mine face,the new node may join and the energy of node may be exhausted along with the network at any time.This requires MAC protocols have a strong adaptive ability to keep pace with the rapid of the scale changing in network load.Papers presented MAC protocol optimization algorithm by introducing competition window diminishing factor,which adaptively adjust the wait time of the sensor nodes to improve energy efficiency and system throughput.At the same time,we proposed a heuristic algorithm to track the change of network load.(2)In emergency mode,MAC protocol should be able to prioritize the delivery of personnel location information,to achieve communications liaison between ground and underground and improve the efficiency of the rescue.paper proposes a service differentiation mechanism based on dynamic Sending-constrainted threshold,setting the dynamic threshold based on the degree of channel congestion.Consequently,data-sending of part of nodes is suitably restrained.On the one hand,the algorithm can use different retransmission mechanism for different priority data streams;on the other hand,effectively increase the system throughput and reduce average packet access delay.(3)In emergency mode,saving energy is the focus of MAC protocol to be considered.To meet Performance requirements for emergency mode of MAC protocol,we proposed a low power consumption WSN MAC protocol on the basis of the last chapter,using scheduling mechanism with asymmetric Quorum system.Simulation and theoretical analysis show that two MAC protocols all have high energy efficiency,fabulous adaptability.So as to emergency relief mode,MAC protocol is more timely and energy-efficient;When it comes to normal mode,the throughput is more high.