Research On Network Coding Based Opportunistic Routing In Wireless Networks

Wireless network has a wide range of applications in real life and it is considered to be one of the most influential and the most significant technologies in 21st Century. Because of the rapid development of wireless network, the quality of wireless communication have become increasingly demanding and using the traditional wired networks'communication methods can not meet people's demand for wireless networks. Besides, the resources of wireless network are very limited and the communication channels are very unstable. How to improve the reliability and throughput of wireless networks, have become one popular research topic.Opportunistic routing and network coding are two kinds of new communication technologies. In recent years, studies have shown that they can produce a great benefit of enhancing the reliability, increasing throughput and saving energy of wireless networks. But most of the studies about these two technologies are separated. How to play the advantages of both tecnologies is an opening problem very worthful to study. We read and analyse a lot of papers and find some shortages. We hope to design a better scheme to play both of the advantages.(1)For the"stop-wait"mechanism of MORE, which lead to there is only one segment of data in the network, because only after the source node received the ACK from the destination node, when it begin sending the next segment of data. In this way, the wait process, between after the source node sending the packets of current segment and before it begin seding the next segment, will affect the network throughput. Our scheme can transmit more than one segment of data simultaneously, and its name is"an algorithm of network coding based opportunistic routing for wireless networks". To solve the problem of MORE's "stop - wait", we let all the nodes in the same hop can communicate with each other when select the forwarding nodes. In this way, it can transmit multiple data segments simultaneously in the network. Theoretical analysis and simulation experiments have proved the superiority of our solution.(2)The protocol of MORE only takes into account intra-flow network coding and not related to inter-flow network coding. Intra-flow network coding is used to solve the problem of the cooperation of relay nodes and it is not impact on the throughput very much. But if it can be combined with inter-flow network coding, it is expected to further improve the network throughput performance. For this we propose a sheme naned"the best scheme of forwarding nodes selection in network coding based opportunistic routing". By analyzing the number of transmissions of several options to determine how many forwarding nodes should be selected to make the number of transmissions minimum. Theoretical analysis and simulation experiments also show the superiority of our solution.Finally, we analyze the disadvantage of our shemes, and hand out our plan of future research directions, and we hope designing much better schemes.