Research On The Adaptive Routing Method Of Lunar Surface Communication Network

The lunar surface communication system network is composed of a large number of noncentralized,and energy limited wireless communication nodes,which have low storage and weak data processing capacity.These wireless communication nodes are randomly distributed in the lunar surface detection area,forming a multi-hop network in a selforganizing manner.But the communication environment of lunar surface is very harsh.Affected by moon dust and craters,the strength of communication signals decreases sharply with the increase of the propagation distance.The lunar surface communication network,as a typical Low-Power and Lossy Network,is characterized by low power consumption and loss.The International Internet Engineering Task Force specifically designed the RPL(Routing Protocol for Low-Power and Lossy Networks)for the Low-Power and Lossy Networks.However,traditional RPL cannot be directly used in the lunar surface communication network.First of all,the surface of the moon is characterized by 14-day polar day,14-day polar night and periodic switching.The network scenarios of polar day and polar night are very different.And the business models of the two scenarios are also different.In addition,the nodes have no energy supply for 14 days in the polar night period.So traditional RPL cannot adapt to the scenes changes of polar day and night;Secondly,the traditional RPL uses a single routing metric to build the network topology,resulting in serious load imbalance in the built network.A routing method called BPSC-RPL based on RPL of the lunar surface communication network is designed in this paper,in order to solve the above-mentioned problems in the existing RPL.First of all,PSC,the node power supply capability index is proposed in this paper,which is obtained by comprehensive calculation of the node’s initial energy,charging efficiency,energy consumption and light intensity factor.The light intensity factor in PSC can effectively perceive the changes in the polar day and night of the lunar surface,and adjust the PSC value adaptively;Secondly,the number of logical hops is positively correlated with node energy consumption.Therefore,both of PSC and logical hops are considered when selecting the optimal parent node,and a triangular modulus operator is used to fuse the two indicators to form a new judgment indicator.The new judgment indicator utilizes the characteristics of similar information enhancement and heterogeneous information reconciliation of the triangular modulus operator,while adapting to changes in the polar day and night of the lunar surface.And the indicator always selects the node with strong power supply capacity and small logical hops as the optimal parent node,which can effectively balance network load and extend network life;Finally,a route compression method based on Bloom filter is proposed in this paper,and the SAX function is used to generate function set,which can compress byte-level routing table into bit-level conversion table without losing routing information.This reduces communication overhead during P2 MP routing,further saving node energy and enhancing network survivability.The Cooja simulator in the Contiki operating system is used for the modelling and simulation of BPSC-RPL to verify its performance.And the results are compared with OF0-RPL,EETX and EHRPL.The simulation results show that BPSC-RPL can effectively reduce the packet loss rate and end-to-end delay,improve network throughput and can reduce the average energy consumption of nodes,balance the network load and extend the network life in the small-scale,low-speed mobile network scenario of the lunar surface.Compared with the other three protocols,the average energy consumption of nodes can be reduced by up to 20%.