Research On Optimization Of SG-NAN Opportunistic Routing Protocol Based On MDP

SG(Smart Grid)is not only a new trend of the plan and development of power grid in the future,but also a hot field of large-scale application of the Internet of things.With the growing maturity of smart grid technology and the gradual expansion of its application scope,how to improve the overall effectiveness of interactive data in the power grid is an important topic for the development of smart grid.In this thesis,SG-NAN(Smart Grid-Neighborhood Area Network)is taken as the research background.And according to the characteristics of the volume of data interaction in SG-NAN,the uplink data transmission of the Network is taken as the research point.Research work was carried out focusing on OR(Opportunistic Routing)protocol in NAN according to the requirements of low latency,high bandwidth,low overhead and so on in the network of SG-NAN.The main work and points of innovation in this thesis are as follows:(1)Firstly,this thesis discusses the background and significance of research and overseas and domestic research status systematically,and studies the network topology,routing protocol,key technical issues and other related theories about SG-NAN.This thesis mainly studies the basic working principle and routing model based on OR protocol,and analyzes the advantages and disadvantages of OR protocol.(2)In the data forwarding stage of OR protocol,the waste of channel resources and the uncertainty and randomness of the forwarding link may be caused by sending the data to multiple nodes adjacent to the sending node by taking advantage of the broadcast characteristics of the radio broadcasting channel.Here introduced MDP(Markov Decision Process)theory,then we designed a kind of opportunistic routing protocol based on markov decision process,named MDP-OR(Markov Decision Process-Opportunistic Routing),and next the routing process of OR protocol is modeled mathematically according to the characteristic of process of state transition in the MDP,and the channel transmission delay,channel capacity and channel overhead of links between each node are jointly defined as the system utility function regarded as routing metric,and finally the routing strategy of the routing protocol of MDP-OR is solved according to the principle of maximizing the total utility function value of the system.(3)In the optimization phase of the routing protocol of MDP-OR,BIA(Backward Induction Algorithm)which is used to solving finite MDP model about random uncertainty problem is analyzed,and the result of analysis about BIA for routing policy is local optimal strategy,according to the optimization principle and the principle of maximizing the total utility value of the system corresponding to the routing strategy in the routing protocol of MDP-OR,here presents a kind of backward induction algorithm based on global optimization,named G-BIA(Global-Backward Induction Algorithm),and finally the optimal routing strategy under MDP-OR is obtained.Finally,MATLAB is used to simulate the improved protocol.Experimental results show that compared with the opportunistic routing protocol based on the routing metric of ETT(Expected Time of Transmission),the total utility value of system corresponding to the routing strategy in the routing protocol of MDP-OR is the largest.Meanwhile,the total utility value of system corresponding to the optimization algorithm of G-BIA under MDP-OR is higher than that of BIA algorithm,that is,the optimal routing strategy obtained has the characteristics of low delay,high bandwidth and low overhead.