Research On Multi-path Routing Protocol Based On Network Coding For Ad Hoc Networks

Ad Hoc network is a novel form of network which is self-constructed, self-organized and self-managed without centralized administration or wired infrastructure. Because of its many advantages such as flexible networking, quick deployment and distributed control, Ad Hoc network is widely used in military and civilian fields. With the characteristic of very limited on-board processing capabilities, highly dynamic topology, poor quality of communication and large propagation delay, routing technology has become the key to improve the network performance.This thesis proposes a multi-path routing protocol based on the network coding calls AMNC (Ad Hoc Networks Multi-path Routing Based on Network Code). The protocol uses random linear network coding strategies based on traditional multi-path routing, then ascertains how many packets need to be forwarded by considering the link quality together with the current received packets. It uses the buffering strategies based on network coding in the transmission. The source nodes send the encoded data, then the intermediate nodes coded the dates and stored in the buffer. If decoding failures, the destination node will sent requests to each intermediate node to retransmit the lost packets. Otherwise if the request failures, the destination node will send a retransmission request to the best node, and then the best node will recode the data which in the buffer after receiving the request. The new coded packets will replace the lost packets and help the destination node encoded the original packets. The algorithm also calculates a maximum allowable rate of each path based on delay and bandwidth. Every route has different flow according to maximum allowable rate to balance the network load.The network simulation software NS2 is adopted to evaluate the proposed protocol. The results show that the proposed routing protocol can effectively improve the network throughput performance, reduce the retransmission of data packets and end-to-end delay, it also can balance the network load with little expense of coding overhead.