The Opportunistic Networks Router Based On Friendship Group

The recent years have witnessed the rapid development of short-range wireless communication equipment and the improvement of manufacturing technology.As a result,a large number of opportunistic networks equipped with short-range wireless communication equipment appeared,such as vehicle network,interstellar network,wildlife tracking network and social network.Most of these networks are set up in extreme environment and special conditions.Under these scenes,the nodes in the network have strong mobility and limited network resources,which leads to the frequent interruption of the connections between nodes in the network.So the nodes cannot establish a continuous and steadily connected network,and the traditional network model cannot run effectively.As a new network model,the opportunistic network,can be better adapted to these challenging environments and meet the communications needs of these environments.To achieve the information transmission amongnodes,the opportunistic networks use the "storage-carrying-forwarding" routing forwarding model.The main goal of routing algorithm is to improve the delivery radio,reduce the average delay and save the cache resource.This paper proposes an opportunistic network routing algorithm based on the friendship group router(FGR),which is applied to the characteristics of the unknown network topology and limited network resources environment.The improvement of the traditional opportunistic networks routing algorithm in this paper is embodied in the following aspects:(1)The division of the friendship group is based on weighted degree of centrality.This paper proposes a concept of weighted degree of centrality to solve the problem of unknown topological topology of the opportunistic network.The whole network is divided into several different friendship groups based on the weighted degree of centrality.The nodes inside the friendship group have higher affinity and meet each other more frequently.In the case of unknown network topology,the division of friendship group constructs the logical topological structure of the network using the meeting history information among nodes.(2)The three-step routing forwarding strategy is based on friendship group.This paper uses the friendship group as the basic network unit to complete the information forwarding process.The forwarding process is divided into three stages: restricted spray stage,outside-group stage forwarding and inside-group forwarding stage.The three-step routing forward strategy can improve the networkdelivery radio and reduce average delay effectively.(3)In view of the limited resources in opportunistic networks,this paper puts forward the management mechanism of message data based on utility degree.Introduce The affinity of two nodes is introduced as a parameter of the utility degree to set up a utility degree list.The message in the node cache is forwarded according to the order of the node’s utility list.When the node cache is not enough to accept new messages,the node will delete the message from the bottom of the utility list until the cache space is sufficient to store new messages.The establishment of utility degree list can achieve the dynamic management of node cache,and improve the situation of insufficient network resources effectively.In order to evaluate the performance of FGR routing algorithm proposed in this paper,the FGR routing algorithm is simulated with ONE simulation platform.The simulation results are compared with the SaW,EBSR,EBRR and Epidemic routing algorithms in three different aspects of comparison: message generation intervals,node caches,and message lifetime.By comparing the delivery radio,average delay and network overhead of those five routing algorithms,we found that the performance of the FGR routing algorithm is better and more stable under various parameters and different environments.