Localized Network Coding Aware Routing Based On Neighbor Topology

Localized network coding has become a hot topic because of its performance gain and practicability in wirless network as a kind of practical network coding.In this paper, we outline the researches on practical network coding, summarize the typical localized network coding schemes and the coding-aware routing algorithms, compare and analyze these algorithms with each other to find out the advantages and shortages。Localized network coding named COPE is used in coding aware routing algorithms, to find out the coding opportuniy that the most packets contain in one encoded pacekts. This paper analyzes the coding opportunity of the localized network coding, and compares the coding probability of two packets with three or more packets. Theoretical analysis and simulation results show that the coding probability of three packets is extremely low and far lower than the probability of two packets even in the dense network.A new topology based coding aware routing algorithm named TCAR is proposed, which is based on the analysis of coding opportunity and relation between the coding opportunity of packets and local topology. TCAR only concerns about the coding opportunity of two packets, detects the coding opportunity depending on the direction of data flows and traffic, and selects the path based on coding opportunity and path length. Simulation results show that TCAR can effectively improve throughput and decrease end-to-end delay compares to COPE.Because TCAR algorithm selects the node that has the most coding opportunities to forward the packets, and the node becomes the bottleneck of network, therefore, a new load balanced coding aware routing named LBTCAR has been proposed, which based on the cross layer design method, denotes the rate in the MAC interface queue as the load information, and combines the coding opportunity and reliability to select transmission path. Simulation results show that LBTCAR can further improve the performance compares to TCAR, which can effectively trade off between the coding opportunity,link reliability and link congestion.