DTN网络环境下动态随机网络编码方法

Method of dynamic random network coding in DTN environment

容迟容断网络的移动性、间歇连通性和动态拓扑等动态特性使得当前应用于静态网络拓扑和固定多播容量的静态随机网络编码难以适应DTN网络环境的网络编码传输,为此提出了一种DTN网络环境下动态随机网络编码传输方法。该方法以马尔科夫信道模型为基础,根据节点的数据状态动态监测信道速率,在信源节点构造了带信道容量的网络流图,并计算和预测当前网络多播容量,最后根据多播容量的变化动态扩展和裁剪随机网络编码方案,实现DTN网络环境下数据的动态网络编码传输。仿真结果表明,相比传统的固定多播率编码方法,动态随机网络编码方法降低了数据的平均传递延迟,提高了数据投递率。

With the dynamical features of mobility, intermittent connectivity and dynamic topology in delay tolerant net- work （DTN）, the static random network coding methods become difficult to adapt to the applications in DTN environ- ment. For working out this problem, a dynamic random network coding transfer method （DRNC） was proposed. Based on the Markov channel model, it first computed the transmit speeds of every network channel according to the receive data states of nodes, and then constructed the network flow graphic with channel capacities at the source node, calculated and forecasted the current network multicast capacity, after that, the random network coding scenario was extended and tai- lored according to the multicast capacity to transmit data packages under DTN environment. The simulation results show that, compared with the traditional random network coding method with fixed multicast rate, the dynamic random net- work coding method has reduced the average latency of data packages and increased the delivery probability.