中文摘要：

为进一步提高无线中继网络的信息传输速率，提出了一种基于复数域网络编码的有效下行传输方案。不同于传统的信息传输方案，该方案采用时间维复数域网络编码，中继节点对接收到的多个时隙的信源符号进行复数域网络编码并将编码符号同时发送给用户节点；用户节点接收到所有中继节点的编码符号，采用联合最大似然多用户检测恢复信源符号。性能分析和仿真结果表明，该方案的符号错误概率明显低于传统中继传输方案，且能获得更高的信息传输速率和网络吞吐量。

英文摘要：

To further improve information transmission rate of wireless relay networks, an efficient downlink transmission scheme based on complex field network coding is proposed in this paper. Specifically, different from traditional information transmission scheme, the proposed downlink transmission scheme employs complex field network coding of time dimension, and each relay encodes the source symbols of multiple time slots received by complex field network coding, and transmits the encoded symbols to destinations simultaneously. Based on the data received from multiple relays, joint maximum likelihood multiuser detection is adopted at destinations to achieve the source symbols. Performance analysis and simulation results show that the symbol error probability （SEP） of the downlink transmission scheme is much less than the conventional relay transmission scheme. Moreover, the scheme can obtain higher information transmission rate and network throughput.