Reseach On Coding-aware Routing In Wireless Network

Network coding is a newly born theory which can enhance the throughput of wireless network by minimizing the transmissions required to communicate data packets. The broadcast essence of wireless channel and the complicated environment in which wireless systems operate offers a perfect scene to apply network coding. The coding-aware routing which combines routing and network coding has recently grown into an important branch of network coding.This thesis proposes a rate-adaptive coding-aware routing protocol and conducts the improvement of it according to the analysis results.On the purpose of full and reasonable use of coding opportunity, this dissertation studies the coding structure of multi-hop coding nodes under different data flow distribution model and proposes a rule called complementary coding condition upon the research. Under different coding structure known as deterministic coding structure and random coding structure, this thesis statics and compares the coding chances created by them respectively. And this article designs a comprehensive judgment norm for the coding-aware routing which combines the coding chances and matched coding rate.This thesis conducts the design of routing message format, it inserts coding chance field and adaptive rate field into the route request message and the route reply message. In the process of routing, an intermediate node can access and change the parameters of these fields. A route request node can determine the best forwarding route sets through the route reply messages it receives. According to the routing rules, this thesis designs the procedure of the new routing protocol and explains the operation of it in detail. Then we conduct the analysis of the performance of new protocol in the well known software network simulation-2.Unreasonable process of matched coding packets conducted by relay nodes will lead to low efficiency of the usage of coding chance, upon this matter, this dissertation proposes an improve manner. Through the establishment of the arriving model of coding packets, this thesis assures two kinds of adaptive packets waiting time that are deterministic waiting time and random waiting time, and changes the manner of coding processes at relay nodes. We use queuing theory to analysis the experimental result at last. To ensure the performance of network coding in different channel environment, this thesis puts forward an adaptive coding mechanism for the reason that reasonable choose whether to perform network coding in different network condition can reduce the bad effect of network coding in a communication system.This thesis conducts simulation of both new protocol and the improved method, simulation results show that network congestion phenomenon caused by network coding can be released by adopting the adaptive-rate coding mechanism. The process at relay nodes of coding packets can improve the utilization efficiency of coding chance, and adaptive network coding ensures more reasonable coding in different network environment.