Design And Simulated Implementation Of Routing Protocol Based On Network Coding Awareness In Wireless Mesh Network

As a new type of broadband wireless access technology, Wireless Mesh Network has the advantages of high transmission rate, wide coverage range and low deployment cost, which is regarded as a more competitive technical solution for wireless terminal access to the Internet. However, critical problems such as limited frequency resources, interference, multipath fading and noise etc., make it difficult to improve the throughput of Wireless Mesh Network. Network coding technology allows and encourages nodes to encode some packets from different sessions and then forward the combinations. Therefore, combining network coding with routing technology could effectively improve the network throughput performance.Based on the network coding theory and wireless multi-hop routing technology, this thesis focuses on how to improve the throughput of Wireless Mesh Network, and carries out the following research work. First, the idea of network coding is introduced on the basis of Ad hoc On-demand Distance Vector (AODV) routing protocol and an opportunity coding based routing protocol (OC-AODV) is designed. Since OC-AODV chooses the shortest path for data transmission, it will cause link congestion and then suppresses the increase of network throughput. In addition, due to the passive detection of coding opportunities after determining route, the available coding opportunities are limited. Therefore, a coding-aware routing protocol (CAR) is proposed, which can actively detect potential coding opportunities in the process of path establishment, and make tradeoff between coding opportunity and hop-count for path selection. Finally, using the cross-layer design ideas, an interference-avoiding coding-aware routing protocol (IACAR) based on CAR is designed to further improve the throughput performance of the network.To evaluate the effectiveness of the proposed protocols, this thesis conducts extensive simulations on NS-2platform. The results showed that the proposed routing protocols can effectively improve the network throughput performance, reduce end-to-end delay and buffer overflow probability of nodes at little expense of control message overhead.