Research On MAC Protocol Of Self-organizing Emergency Transmission Network In Complex Environment

Emergency communication is often faced with the problems of complex communication environment,complex regional environment and easy to damage fixed equipment.The characteristics of self-organization network are strong,no center and self-organization in antidestruction.Among them,the MAC protocol directly affects communication quality and network efficiency of emergency transmission network in self-organizing network.However,traditional MAC protocol is not suitable for self-organizing emergency transmission network due to the collision of packet conflict and user priority access.The complex environment referred to in this paper the emergency scene where fixed infrastructure such as base station and optical cable are damaged,and communication quality is poor.In order to ensure the efficient and reliable transmission of emergency transmission network,and enable the timely and reliable transmission of high priority user messages,this paper studies MAC protocol for channel load statistics and channel access control,and verifies and analyzes the performance of the algorithm through simulation platform and protocol verification platform.On the one hand,aiming at the problem of insufficient link resources and coexistence of each priority user in the self-organizing emergency transmission network in complex environment,based on the statistical priority multiple access protocol,a statistical priority MAC protocol for emergency transmission is designed to maximize the transmission requirements of high priority users.This protocol determines whether the packet is connected to the channel according to the statistical value of channel load and priority threshold.The protocol is simulated and verified by the simulation platform with the end-to-end delay,packet transmission success rate and system throughput as performance indicators.The simulation results show that the protocol can guarantee the high access probability and high transmission success rate of high priority packets under the condition of high system load,and the end-toend delay is stable for 2.6ms.In addition,the protocol verification platform is built by using edge nodes combined with Tiny OS operating system,and the performance index of the protocol is further verified.On the other hand,in the face of the emergency situation in complex environment,the proportion of priority services is not fixed.In view of the lack of adaptive ability of the existing emergency transmission network,it is difficult to meet the communication needs with emergency state,so a MAC protocol based on adaptive channel access algorithm is designed.Firstly,real-time sensing and statistics of channel usage in self-organizing emergency transmission network are performed.Secondly,according to the channel occupancy and the urgency of the service,the packet access to the network is decided.Finally,the success probability of packet transmission is analyzed theoretically.The simulation and protocol verification platform show that compared with the statistical priority MAC protocol for emergency transmission,the protocol has better network performance under the condition of high system load.