Feng Yizhi, Cao Yan
School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China.
The National Engineering Technology Research Center for Mobile Ultrasonic Detection, South China University of Technology, Guangzhou 510640, China.
Sensors (Basel). 2022 Apr 15;22(8):3041. doi: 10.3390/s22083041.
In this paper, the maximization of the achievable information rate is proposed for the multi-relay amplify-and-forward cooperative simultaneous wireless information and power transfer communication systems, where the nonlinear characteristic of the energy harvesting (EH) circuits is taken into account for the receivers of the relay nodes. The time switching (TS) and power splitting (PS) schemes are considered for the EH receivers and the achievable rate maximization problems are formulated as convex and non-convex optimization problems, respectively. The optimal TS and PS ratios for the relay nodes along with the maximum achievable rates for the system are obtained, respectively, by solving the optimal problems with efficient algorithms. The asymptotic maximum achievable rates at low and high input signal-to-noise ratios (SNRs) for both the PS and TS schemes are also analyzed. It is demonstrated that the PS scheme is more susceptible to the variation of the relays' location and the channel parameters than TS scheme, whereas the TS scheme is more susceptible to the mismatch of the resource allocation than PS scheme. Specifically, compared to the linear EH model, the nonlinear EH model achieves significant performance gain for the TS scheme, whereas inconspicuous performance improvement is achieved for the PS scheme.
本文针对多中继放大转发协作式同时无线信息与功率传输通信系统，提出了可实现信息速率最大化的方法，其中中继节点的接收器考虑了能量收集（EH）电路的非线性特性。针对EH接收器考虑了时间切换（TS）和功率分配（PS）方案，可实现速率最大化问题分别被表述为凸优化问题和非凸优化问题。通过使用高效算法求解最优问题，分别获得了中继节点的最优TS和PS比率以及系统的最大可实现速率。还分析了PS和TS方案在低输入信噪比（SNR）和高输入信噪比时的渐近最大可实现速率。结果表明，与TS方案相比，PS方案对中继节点位置和信道参数的变化更敏感，而TS方案比PS方案对资源分配的不匹配更敏感。具体而言，与线性EH模型相比，非线性EH模型在TS方案中实现了显著的性能增益，而在PS方案中实现的性能提升并不明显。
