无线网络中应用机会式网络编码的广播重传方法

A Broadcast Retransmission Method Using Opportunistic Network Coding in Wireless Networks

为了提高无线网络中数据包的传输效率,提出了一种利用机会式网络编码的无线广播重传方法(WBR方法).该方法在基站先以最小重传次数下限为约束条件选择编码数据包,再传输采用机会式网络编码方法生成的组合重传包,在终端从收到的单个或多个组合重传包中恢复丢包.由于选择了更多的丢包编码生成组合重传包,使终端能从更少的组合重传包中恢复其丢包,从而有效地减少了广播重传次数.相比传统自动重传请求方法和基于网络编码的重传方法,WBR方法具有传输效率更高的特点.仿真结果表明,与自动重传请求方法和已有的基于网络编码方法相比,WBR方法的平均广播重传次数最少,而且相比自动重传请求方法的平均重传次数减少了55%.

A novel wireless broadcast retransmission method （WBR） is proposed to improve transmission efficiency over wireless networks. The lost packets from multiple terminals are selected subject to the lower-bounds on the minimum number of retransmissions at base stations. Then the selected packets are combined to generate retransmission packets by employing the opportunistic network coding. Finally, the lost packets are retrieved at terminals from the transmitted retransmission packets. Because the number of retransmission packets is less than that of lost packets, the proposed method can improve network transmission efficiency significantly. Comparisons with the automatic repeat request（ARQ） method and the existing network coding （NC） based methods show that the improvement obtained from the WBR method is clear. The simulation results show that the average number of retransmissions of WBR method is 55% less than that of ARQ method, and the WBR method also outperforms the existing NC based methods.