Research And Implementation Of Efficient Routing Protocols In Opportunistic Networks

The concept of Opportunistic network comes from Delay Tolerant Network(DTN). As a new type of Mobile Ad hoc Networks(MANET), the nodes in the network makes full use of the communication chance created by each other to transmit the messages and a complete end to end communication link between both sides not required. Due to the frequent movement of the nodes in the network, the temporary establishment of the communication connection is often interrupted. A n efficient routing protocol design therefore becomes the key point in opportunistic networks in view of the characteristics of opportunistic networks. This paper discusses and studies the routing algorithms which are widely used in opportunistic networks and finally design and implement a new routing algorithm.Taking the high efficiency design of routing design as the starting point, a hybrid routing algorithm named PMSF which is based on Prophet delivery probability and Markov model has been proposed to improve the Spray and Wait routing algorithm which stands on the perspective of efficiency. In the Spray phase, the transmission potential and reliability of relay nodes are fully considered and the copies of the messages are distributed according to the delivery probability designed in the Prophet algorithm, which makes the forwarding decision more sensible. In the update process of delivery probability, the design of routing credibility is introduced, which makes the whole message transmission process more stable and more efficient.In the PMSF routing algorithm, the Wait phase is changed into the multi hop forwarding phase of active routing. The meeting time interval of nodes reasonably predicted by Markov model and the node that can meet the destination node in the shortest time interval will be chosen as a relay node. In the whole routing process, the buffer management strategy based on ACK acknowledgment is introduced, which can effectively alleviate the problem of network congestion. Through a lot of simulation experiments to verify the effectiveness and efficiency of the proposed algorithm, the results show that the proposed algorithm has a better performance in terms of message delivery ratio, delivery latency and routing overhead.