Research On Error Control And Routing Protocol In Opportunistic Networks

Opportunistic Network (ON) is a kind of wireless ad hoc networks with intermittent connection properties, and several concepts behind opportunistic network come from the studies on Delay Tolerant Networks (DTNs). With the appearance of plenty of smart devices equipped a short-distance communication, wireless ad hoc networks also advance rapidly. In the real network, nodes random mobility or periodically dormant, electromagnetic interference, radio frequency closure, barrier disruption and other reasons result in the network frequently disconnect, which led the end-to-end fully connected path between the source and destination does not exist. As long as the nodes move randomly, they can transmit the messages hop by hop in networks in the simplest and most reliable form of"store-carry-forward"paradigm by taking the communication opportunity of mobility. The brand new communication mode has aroused close attention of researchers in recent years.This paper will introduce the concept, features and key technology and of ON, and categorize the existing error control technology and routing protocols of Opportunistic Networks. At same time, in view of the "storage-carry-forward" routing mode, there are many copies of the same information, and the network can not take advantage of the multiple copies, so we proposed the NER(Error Recovery Based on FEC in Network-layer) error control mechanism; Then, based on Epidemic routing and the NER mechanism, proposed NER-DRP(Dissemination-based Routing Protocol with Network-layer Error Control) routing protocol, to make full use of the copies and in order to improve the chance of successful delivery ratio of packets; Finally, in consideration of the NER-DRP routing protocols do not take full advantage of multiple partially error copies, but such copies have most high successful merger probability, which introduce the"merger probability"into buffer management, NER-DRP-P (Dissemination-based Routing Protocol with Network-layer Error Control and Probability)routing protocol is proposed to further improve the successful delivery ratio and reduce end-to-end delay.We chose NS-2 as simulation tool to simulate Epidemic, NER-DRP and NER-DRP-P routing protocols. The simulation results show that the improved NER-DRP and NER-DRP-P protocol hava better performance than the original Epidemic protocol on delivery ratio, End-to-End delay and average hop-count.