Research On Wireless Communication Technologies For Smart Grid Neighbor Area Network

Smart grid is an intelligent power two-way communication network integrating information,control,communication,power and other technologies.It can significantly improve the performance of traditional power network such as robustness,effectiveness and reliability,and make the power grid more efficient,intelligent,safe,clean,economical etc.Smartgrid mainly includes power network and communication network.And communication network,the core part to realize smart grid communication,mainly includeshome area netwok(HAN),neighbor area network(NAN)and wide area network(WAN).Among them,NAN,mainly responsible for realizing the interaction of various kinds of information between HAN and WAN,is the key component of the smart grid communication network.NAN is a kind of low-power and lossy network for its communication environment is harsh and complex,and its nodes and links between nodes are constrained.Therefore,it is very important to study the efficient and reliable communication technology of NAN,and the research and design routing protocol of NAN is the most important.At present,several studies have pointed out that the routing protocol for low-power and lossy networks(RPL)can be applied to NAN.However,this protocol is not specially designed for NAN and cannot fully meet the application requirements of NAN.Therefore,based on RPL,this paper designs several routing protocols to meet the application requirements of NAN and realize the efficient and reliable operation of NAN.This paper focuses on the research and analysis of various wireless communication technologies currently applicable to NAN.Secondly,several routing protocols suitable for NAN are designed based on RPL.Finally,these newly designed NAN routing protocols are compared and analyzed.The specific research contents are as follows:1.The research on wireless communication technologies for NANThrough wireless communication technology,NAN can collect,transmit and process information efficiently and flexible.Firstly,the wired and wireless communication technologies used in NAN are compared and analyzed.Secondly,the wireless communication technologies used in NAN are deeply studied.Finally,it is proposed that the hybrid wireless communication technology can improve the network performance and meet the application requirements.2.RPL routing protocol for NAN based on triangle module operatorThe existing RPL and some of its improvements only consider single routing metric such as hop count when topology construction or routing selection.And the capabilities of candidate parents are not comprehensively evaluated.Moreover,several studies have proposed to evaluate candidate parents according to two or three routing metrics,but the weight factor of each routing metric is mostly based on the experts'personal experience,which is too subjective.Therefore,RPL based on triangle module operator for NAN(RPL-TMO)is proposed in this part.RPL-TMO proposed to adopt composite routing metric in network topology construction and routing selection,which comprehensively evaluated delay,hops,ETX,residual energy and number of child nodes of the candidate parent.Then the membership functions of these routing metrics are proposed.Secondly,RPL-TMO proposed to fuse membership functions of these routing metrics based on triangle module operator to construct a new composite objective function.Thirdly,RPL-TMO determines the possibility of each candidate parent node becoming preferred parent(the nexthop)according to the maximum membershipprinciple.Fourthly,RPL-TMO proposed the new node rank value calculation and preferred parent selection mechanisms,so as to select the best node as the preferred parent.Finally,series ofsimulation results show that RPL-TMO can significantly improve the network performance and fully meet the application requirements of NAN.3.RPL routing protocol for NAN based on chaotic genetic algorithmTo solve the problems of failing to comprehensively evaluate the routing metrics of candidate parent,or there is no scientific theoretical basis for routing metrics' weight distribution when evaluating several routing metrics.RPL routing protocol for NAN based on chaotic genetic algorithm(RPL-CGA)is proposed.RPL-CGA proposed that the bufferqueue length,delay,residual energy,hop count and ETX of candidate parent should be comprehensively evaluated when selecting the preferred parent.Then the mathematical analysis is given to prove that all the above routing metrics meet the characteristics of consistency,optimality and no loop,and can be combined into composite routing metrics.Secondly,RPL-CGA proposed composite routing metrics and composite objective function based on the above routing metrics.Thirdly,RPL-CGA proposed to determine the weight coefficient of each routing metric based on chaotic genetic algorithm.And the weight coefficient distribution can be changed in real time according to the actual operation of the network.Fourthly,RPL-CGA proposed the new rank value calculation and preferred parentselection mechanisms.Finally,the effectiveness and reliability of RPL-CGA are proved by series ofsimulation experiments.4.RPL routing protocol for NAN based on fuzzy analytic hierarchy processIn this part,a novelRPL routing protocol for NAN based on fuzzy analytic hierarchy process(RPL-FAHP)is proposed.RPL-FAHP proposed that when choosing preferred parent,the residual energy,ETX,delay and hop count of candidate parent should be comprehensively evaluated.Secondly,RPL-FAHP proposed a new composite objective function and used fuzzy analytic hierarchy process to determine the weight coefficient of each routing metric in the composite objective function.Thirdly,the mechanism of reconciliating the candidate parent set size and RPL-FAHP execution is proposed.Finally,theoretical analysis and simulation results show that RPL-FAHP has advantages over other typical protocols in terms of network lifetime,delay,etc.5.RPL routing protocol for NAN based on combination weighting methodTo solve the problems of high control overhead,high energy consumption and no reasonable weight distribution theory can be used to determine the weight coefficients of routing metrics in the composite objective function,RPL routing protocol for NAN based oncombination weighting method(RPL-CWM)is proposed.RPL-CWM proposes a new DODAG build process to reduce control overhead and improve network build efficiency.Secondly,RPL-CWM proposes a new context aware composite routing metric(CAC-RM),which comprehensively evaluates the residual energy index,buffer occupancy,ETX,delay and hop count of candidate parents during topology construction and routing selection.CAC-RM adopts an iterative method to evaluate residual energy ratio and buffer occupancy ratio of candidate parent i and the preferred parent of i,so as to further consider the influence of parent.Meanwhile,CAC-RMproposes a method to evaluate the quality of the path through a candidate parent by using the sum,mean and mean square deviation of ETX and delay of each link on the path.Thirdly,RPL-CWM proposes a new context aware composite objective function(CAC-OF)and determines the weight coefficient of each routing metric in CAC-OF through the combination weighting method.Fourthly,RPL-CWM proposed new rank value calculation and preferred parent selection mechanisms.Finally,the simulation results show that RPL-CWM is better than the existing representative RPL-related protocols in control overhead,network lifetime,etc.So RPL-CWMcan be applied to NAN more efficiently.6.Comparative analysis of several new RPL routing protocols for NANThis part mainly compares and analyzes the abovementionednewly proposed RPL routing protocols for NAN.It also points out the understanding of desiging routing protocol for NAN and provide a certain theoretical basis for future research.Finally,the summary and the future research directions of this thesis are given.