Research On Routing Algorithm Based On Load Balancing In Delay/Disruption Tolerant Networks

With the development of wireless communication technology,some new forms of network begin to emerge, such as IPNRG, wildlife monitoring network, the mobile vehicle networks(VANET), underwater sensor networks, pocket-switched networks. In these networks, due to the sparsity of nodes, high degree of mobility, limited communication range, usually, there does not exist a continuous, stable, end to end link. This kind of network is known as the challenges network, also known as the Delay/Disruption Tolerant Networks(DTN). TCP / IP protocol has high demands on network stability, connectivity, so it can not apply to DTN for messages'transmission, DTN message delivery using a "store - carry - forward" mechanism.DTN has highly dynamic and instability topology, and there often exist high latency and disruption in it. So it is difficult to delivery message reliably and fast in DTN. The main goal of DTN routing is to ensure the ability to deliver messages at a high delivery probability and a low delivery latency. In the actual case, the node's energy is often very limited, in order to ensure the performance of DTN, it is necessary to prevent the energy of a part of nodes from premature depletion. Meanwhile, the node generally has the characteristics of heterogeneity such as initial energy and energy consumption model. Existing routing algorithms focused on improving the delivery probability and reduce the delivery delay , there is few routing algorithms for the above situation. In order to solve this problem, this paper proposes an algorithm based on nodes'heterogeneity and load balancing, Fair Spray and Wait routing(FSnW for short). FSnW has improved the spray phase of SnW. In FSnW, when two nodes come into contact, the copies of message they keep is proportional to their remaining energy. In the simulation section, when the energy of nods is limited, FSnW routing has a better performance than SnW and Epidemic, it can preliminary ensure load balancing between nodes. However, Although FSnW can ensure the load balancing to some extent, it cannot guarantee the effectiveness of delivery. In spray phase, copies of message may be delivered to the nodes of low transmission capacity, and then the performance of the whole network will become worse. To cope with this problem, this paper has introduced and improved the conceptions of"status"and"utility"in FairRoute algorithm, and applied the two conceptions to FSnW, proposed an UFSnW routing. UFSnW set constrains of status and utility for the message delivery in spray phase, which can improve the delivery effectiveness. In the simulation section, when nodes'energy is limited, UFSnW has higher delivery probability and lower delivery latency than the other two.