Research On Message Residual Value Aided Binary Spray And Wait

Delay Tolerant Networks (DTN) is a novel kind of network evolving from Mobile Ad Hoc Networks, which aims at resolving the data communication for intermittently connected environment. Due to the nodal mobility, dynamic topology, and limited network resources, it is impossible to establish stable path between the nodes in DTN, and traditional routing algorithm of Mobile Ad Hoc Networks can not guarantee the effectiveness and continuity of data transmission.Being different from the traditional mobile ad-hoc networks, nodes in DTN transmit data through collaboration between nodes by "store-carry-forward" manner to deal with the unstable link caused by varied topology. Obviously, DTN can be applied to complex network environments and the research of it can provide strong support for the development of ubiquitous network.DTN is a kind of restricted network which is either non-connected or intermittently connected. In order to delivery packets in a challenging network environment, two most important problems should be considered:routing strategy and buffer space management strategy. The routing strategy determines which message will be forwarded when the nodes meet; buffer space management strategy determines which message will be discarded when a node’s buffer space overflows.In this thesis, main works are as follows:(1) This thesis first introduced the research background of DTN, the application of it in the region with poor or unstable environment, research status of DTN and the achievement of congestion control, both in China and abroad, were also introduced here. In order to understand and study the DTN better, network structure of DTN routing, comparison between the characteristics of DTN and the features of traditional network, the concept of custody transfer and transport mechanism of DTN were also introduced.(2) Single-copy and multi-copy routing protocols that exist in the DTN were explained specifically, and the advantages and disadvantages of these two protocols were compared. In order to ensure the communication quality of multi-copy routing protocols in DTN, the congestion control strategy based on multiple copy routing protocols was presented in this thesis and some proposed congestion control strategies were also introduced in detail.(3) This thesis presented a kind of algorithm, which was called Message Residual Value aided Binary Spray and Wait. Residual value of the message was defined by message copies and message delivery delay. The algorithm of residual value can be designed through these two factors, and a new queuing strategy can be proposed by using message residual value. When coming across other nodes, the source node and relay node would prefer to transfer the message with more residual values. When there is insufficient buffer space, they prefer to delete messages with less residual values and set aside enough buffer space for the newly arrived message.(4) Through ONE simulation platform for simulation. Experiment results demonstrate that the proposed MRV-BSW can increase the message delivery efficiency and reduce the delivery delay without aggravating network overhead obviously, mitigating the influence of network congestion significantly, enabling Binary Spray and Wait to have better adaptive capacity when it is in congestion.