针对无线组播网络中降低数据包重传次数及对抗信道衰落、建立稳定无线连接的需求,提出了一种基于网络编码的动态组合重传算法。该算法采用动态线性组合编码算法(DLCCA),以提高无线组播网络带宽利用效率。首先,利用发送端向用户发送原始数据包;其次,通过组播网络的控制信道,发送端获取了网络用户的接收状态,对未正确解码的数据包进行编码,并在传输过程中根据网络状态采用动态组合策略来形成网络编码包,从而有效提高了网络的整体吞吐量。与此同时,还进一步提出了低复杂度编码算法,并分析了所提编码算法的性能,获得了相应的理论分析结果。仿真实验表明,与传统的无编码算法和XOR网络编码算法相比,动态组合重传算法可以显著减少30%的数据重传次数,提高了网络吞吐量。
A retransmission algorithm with dynamic linear combination based on the network coding is proposed to meet the demands for decreasing the packets retransmission, to overcome the wireless channel fading, to build reliable wireless connection and to improve the efficiency of the bandwidth utilization in multicast networks. A dynamic linear combining coding algorithm (DLCCA) is used in the algorithm. Firstly, the transmitter in DLCCA sends original packets to users in the network. Then, the transmitter obtains the receiving status feedback from the users through control channel, and encodes the original packets that have not been correctly decoded by the users. Meanwhile, the encoding strategy is dynamically adjusted based on the network status so that the network throughput is improved. Furthermore, a coding algorithm with lower complexity is proposed, and the performance of the coding algorithm is analyzed. Theoretical result is obtained through analysis. Simulation results and comparisons with the transmission algorithm without network coding and the traditional XOR network coding algorithm show that the proposed algorithm greatly reduces 30% of packet retransmission, and the network throughput is increased.