协作通信网络中基于Lagrange算法的中继选择和功率优化方案

协作通信技术可以有效获取空间分集,并进一步改善系统的性能。为最小化多中继解码转发(decode-and-forward,DF)协作通信系统的总功率,同时满足系统要求的数据传输速率,提出了一种基于Lagrange算法的中继选择和功率分配的联合优化方案。首先根据信源与中继的瞬时信道状态信息(channel state information, CSI)使信源的发送功率最小化,然后选择出最大的可解码中继集合,再利用Lagrange算法对中继功率进行优化,根据得到的信源和中继的功率分配,选择出最佳中继集合,达到最小化系统总功率的目的。仿真结果表明,相对于直传方案和机会中继(opportunistic relay selection, ORS)方案,本研究中总功率消耗明显减少。

The Lagrange algorithm based relay selection and power optimization in a cooperative system

Cooperative communication technology can efficiently achieve spatial diversity and improve the system performance.In order to minimize the total power consumption and satisfy the data rate requirement of a decode-and-forward(DF) multi-relay cooperative system,an optimized Lagrange algorithm based relay selection and power allocation scheme was proposed.Based on the utilization of the instantaneous channel state information(CSI) between the source and the relays,the minimal transmit power of the source and the largest decoding relay set could be obtained.With the application of the Lagrange multiplier technique,the power allocation for the source and the relays could be obtained,and the best relays could be selected from the decoding relay set to minimize the total system power consumption.Simulation results showed that the total power consumption of the proposed scheme was significantly reduced compared with that of the direct transmission and the opportunistic relay selection(ORS) scheme.