Research And Implementation Of The Selection And Optimization Of The Terminal Multichannel Access Protocol At The End Of The IoT

With the continuous development of network technology,the future communication system will become more complex,a variety of wireless technology coexistence is an inevitable trend.In the network access technology,the different network has its own advantages and disadvantages,in the network access technology has its own characteristics,no one network can be in the bandwidth,delay,jitter,coverage and so on a full range of users to meet the network needs.In order to better serve the application of different service types in the network,network fusion technology becomes very important.The fusion technology of heterogeneous networks is mainly embodied in the realization of seamless switching of terminals under heterogeneous wireless networks under the precondition of fully utilizing the resources of the whole network system.So the high performance vertical handoff algorithm becomes its core.In the vertical handoff,the network selection algorithm is the most important problem.Traditional network selection algorithms can not take into account the quality of Network service and network resource utilization.Aiming at the problems of traditional network selection algorithms,this paper focuses on how to improve the network service quality of the network while improving the utilization of the resources and reducing the congestion rate.1.How to improve the network service quality of the terminal.This paper presents a network selection model based on business type.Through the detailed analysis of various network applications in the real scene,we get the different demand of network performance of different service types,then use the AHP method to determine the weights of each attribute of the network in different service types.This provides a prerequisite for the design of the network selection algorithm.2.An improved network selection algorithm based on MDP is proposed.In the premise of distinguishing the service type,the network selection algorithm is established by Markov model.The income function is constructed at each terminal when the network chooses to switch,and the time scale is lengthened to get a discontinuous function sequence.In order to optimize the performance of the network for a long time,we can get the expected profit of the terminal network switching in the weighted way.Finally,we can get the maximum benefit in this time by numerical iterative method.The optimal network selection strategy is obtained.3.The experimental analysis shows that the algorithm which distinguishes the service type in this paper has a great improvement on the network performance compared with the algorithm without distinguishing the service type.The improved network selection algorithm based on MDP also has a significant improvement on the long-term network.Overall,this method can improve the utilization of network resources,effectively reduce the network congestion rate,but also to meet the different terminal network access requirements.