一种无人机协同通信系统中继转发协议研究

A Research of Relay Forward Protocol in UAV Cooperative Communications

将无人机作为通信中继来辅助完成超视距信息交互,当通信双方进行信息交互时,采用两路中继模型,针对不同信道状态下的转发协议调度问题,提出了自适应解调转发(Adaptive Demodulation-Forward,ADMF)协议和混合型转发协议。将直接解调转发(Demodulation-Forward,DMF)协议和差分DMF协议相结合,以两条链路传输符号的对数似然比为仲裁依据,自适应地根据不同的信道状态调度合适的中继转发协议。进一步设置对数似然比阈值,提出混合型转发协议,仅在信道衰落严重的情况下在中继端进行信号解调。经仿真得出,混合型和ADMF协议的误包率性能明显优于前两种转发协议,其误码性能在误符号率为10^(-2)时信噪比损失减少约5dB。

UAVs can be used as communication relays to help conducting information exchanging beyond visual range.When two communication nodes communicating with each other,two-way relay channel is used.To solve the problem of different forwarding protocol scheduling for variable channel states,adaptive demodulation-forward protocol is proposed.It combines direct demodulation-forward protocol and differential demodulation-forward protocol,adaptively chooses the appropriate protocol using the LLRs of the symbols transmitted as the decision criterion through each channel.Furthermore,hybrid forwarding protocol is proposed based on the total channel condition.The simulation results show that the packet error rate performance of the two protocols proposed are better than the other two forwarding protocols,and the bit error rate performance is that the SNR loss is 5dB less when the SER is 10^(-2).