Research On Adaptive Routing Method For Wireless Weak-connected Network

With the rapid development of multi-hop communication between mobile terminals,people have put forward higher demand for wireless network communication.However,most existing wireless networks assume that there is at least one complete end-to-end link during communication,and usually adopt a method called "first routing last transmission" to achieve resource sharing and data communication.But in some special scenarios with harsh communication environments,due to frequent movement of nodes and intermittent link connection,it is difficult to establish a complete link from the source end to the destination end during the communication,resulting that the traditional network routing method is no longer suitable for the communication requirements of the network in this scenario.Therefore,it is very necessary to study the routing problem of intermittent connected networks.This thesis defines a wireless weak-connected network(WWN),which is a special self-organizing network.Nodes move randomly in the deployment area,and the communication link connections exhibit extreme unstable characteristic,which makes the whole topology of the network complex and changeable,along with the network appearing intermittent connection phenomenon.Therefore,relying on the mobility of nodes to form a short-term connected sub-network when communication is needed to achieve best-effort routing and data communication.Physarum polycephalum can self-organize and spread out to form an effective foraging network.Hence,based on its inspiration,this thesis utilizes the model mapping method from the foraging network of Polycephalum polycephalum to the wireless weak-connected network,to conduct an in-depth research on the routing problems of wireless weak-connected network with time-varying topology,aiming to improve network performance through optimized routing method.The main research works include the following four aspects.(1)Analyzing the intelligence and adaptability of Physarum polycephalum in foraging process,the thesis establishes a mathematical model of the Physarum polycephalum foraging network,and abstracts fluid flux,conductivity,node pressure difference,pipeline length,etc.(2)Analyzing the unstable link and dynamic topology characteristics of wireless weak-connected network,the thesis establishes a bio-inspired wireless weak-connected network model via mapping the biological model,and derives the mathematical expressions of link capacity,link connectivity,node regulation rate,link length and other parameters.(3)Introducing some factors such as node mobility stability,the degree of node congestion,and link quality,the thesis proposes an adaptive routing method for wireless weak-connected network and designs the next hop selection strategy and optimal routing strategy to complete the data transmission in intermittent connected network.(4)In the experiment,selecting three key indicators of the delivery ratio,average delivery delay,and overhead ratio,the thesis carries out experimental simulations from four aspects,including the number of nodes,node buffer size,node movement speed,and the time to live of data packet,and studies their impact on the performance of each routing algorithms.The simulation results show that the proposed algorithm achieves higher delivery ratio and shorter average delivery delay when the network overhead ratio is relatively low.