The Reasearch Of MANET Network Reliable Routing Technology

Due to features of self-organiazation and self- healing, mobile Ad Hoc network has been used in military tactical communication, emergency communication and other fields. However, the mobility of nodes, joining and leaving network, external interference and other factors cause the network links and topology change frequently, make path less stable, and reduces the communication performance seriously. Especially in military tactical wireless communication network, the malicious jammer makes the change of network links and topology more unpredictable, and seriously affects the path stability and communication performance. Therefore, in order to ensure the reliability communication of end to end nodes, this article studies the robust routing technology from the perspective of time domain, spatial diversity in network layer, improves the reliability of data transmission, and achieves the goal of resisting external interference and constructing a robust network.Firstly, aiming at the stochastic network interference, we adopt time domain redundancy technology, which refers to redundant coding at source to improve the reliability of data transmission. Because the fixed coding redundancy can’t adapt to the dynamic network environment, conservative and overmuch redundancy will increase the network load and node processing overhead. therefore, this article design an adaptive coding redundancy scheme, which can adjust the size of coding redundancy according to the current network condition, and make the coding efficiency best. Compared with the fixed coding transmission method, adaptive redundant coding scheme can achieve higher packet delivery ratio, improve the reliability of data transmission through the OPNET simulation and analysis.Secondly, when the jammer can only affect the network partial region, the node and link affected by the jammer have regional difference, we use the spatial redundancy technology, which can establish multiple paths between source and destination to improve the packet delivery rate by the mean of designing some path metrics such as path disjiontness, path reliability and so on. And when the network environment is instable, the path quality is very bad, we can use a combination of temporal and spatial redundancy transmission technology to improve the network communication performance.Finally, in order to adapt to the dynamic network environment, we go further and propose a hybrid routing mechanism called adaptive mul-coding routing protocol(ACMR). Based on the perception of packet delivery ratio, the protocol can switch in four types of routing modes, which are singe path routing mode, single-code routing mode, multipath routing mode, mul-code mode. When the network condition is good, the protocol use single path transmission mode, and reduce the network cost. When the network condition becomes bad, it switchs to a more reliable data transmission mode. Through OPNET simulation analysis, compared with the single routing mode, an adaptive mul-coding can not only improve the reliability of the network, but also can adpt to dynamic network.