高损耗无线网络中基于网络编码的广播重传策略

High loss wireless broadcasting retransmission scheme based on network coding

利用网络编码减少无线传输信息量的原理,结合高损耗无线广播丢包特点,提出多接收节点情况下网络编码组合重传的方法,给出基于网络编码的高损耗无线网络广播重传策略。通过对广播节点保存的信息接收情况矩阵进行丢失概率排序得到新的接收情况矩阵,再按照基于网络编码的多节点编码组合定理寻找满足可解性条件的丢失包组合。对于广播节点,将丢失包组合存入发送序列,进行编码组合,广播发送;对于接收节点,得到编码组合包,进行解码操作,解出丢失包。理论分析结果表明:策略中的编码信息包在所有接收节点具有可解性,可以达到重传目的。模拟测试表明:不同的节点丢包率和广播接收节点数目下,与逐个重传的策略相比,发送次数显著减少。尽管节点需要更大的计算能力,但是可以接受,策略可行。

Based on the physical-layer broadcasting property offered by the wireless medium, the number of transmissions was saved in the packets transmits by network coding. Combined with the drop feature of high loss wireless broadcasting, a novel retransmission scheme in high loss wireless broadcasting based on network coding was presented. Retransmission packet lists were generated based on the probability of information packets, and then information packets were coding combined using network coding theory. In broadcasting nodes, packets were collected and sent; in received nodes, combined packets were decoded and got the lost packets. The theoretic analysis shows that the approach ensures the solvability in the received nodes and achieves retransmission. The simulation results indicate that comparing with traditional scheme, the scheme effectively reduces the average number of transmissions. The greater computing abilities are required than the original approach, but the overhead is reasonable and the approach is effective.