Research On Wireless Transmission Based On Network Coding

With the rapidly development in wireless technologies and transmissions, how to ensure the reliability and security in wireless transmission links and how to enhance the efficiency of wireless resources are becoming the important problem in wireless communication research areas.Network coding, an elegant transmission paradigm, was recently proposed by network information theory. The key idea is that if we allow intermediate nodes in the network to not only forward but also to process the incoming information flows, we may get significant benefits. This paper focuses on the reliability and security of wireless transmission links and the wireless routing improvement, and investigates the wireless broadcasting retransmission approach with network coding, the wireless batch packets handle mechanism with linear network coding, the malicious detection approach based on network coding and the wireless routing metric measurement.Firstly, this dissertation gives a survey of researches of wireless transmission with network coding. Primary technologies which used in wireless transmission with network coding are classified and analyzed. We also propose some open problems.In the main part of this dissertation, we research the reliability problem and security problem of wireless transmission; we focused on the wireless broadcasting retransmission and the malicious nodes detection, and bring different approach for different factors.In view of the existent problems and shortages of the traditional retransmissions approach, we propose a new wireless broadcasting retransmission approach with network coding, which brings and analyses the combination theorem and the sending algorithm. Simulation results indicate that compared with existing approach, the approach in this paper can effectively reduce the average number of transmissions and advance the transmission efficiency. Simultaneity, we introduce an improvement approach which can achieve better performance in high loss wireless network.A new retransmission approach with batch packets handle mechanism is also proposed in this dissertation. The novel approach detaches the transmission packets to several batches and sends linear coding packets based on the largest mounts of lost packets in different batches. Mathematic and simulation analysis reveals that our approach can ensure the solvability in the received nodes, and have optimal performance in wireless retransmission.As to the problem of malicious node detection, we present a novel malicious detection approach in wireless networks based on network coding, whose key idea is to using the characteristic of information exchange to validate the information packets. The neighbor nodes of sending node will judge the malicious behaviors by detecting the packets data and data's hash. Theoretical analysis reveals that our approach can detect the malicious node in high probability and advance the transmission efficiency.Aiming at the problem of routing metric measurement in wireless networks, an improved cost metrics approach based on network coding is proposed, whose key idea is to use the traffic parameter to measure the "rid" degree of the flow and get the cost of the path while the path uses network coding. Analysis and simulation results indicate that the approach introduced in this paper can find the lower cost path effectively and advance the transmission efficiency.Our research of the wireless transmission with network coding will lay a significant theoretic basis for the practical application of wireless transmission in the real transmission circumstance.