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    具有SWIPT和自能量回收的非分时全双工中继系统

    Non-Time-Switching Full-Duplex Relay System with SWIPT and Self-Energy Recycling

    • 摘要: 应用无线携能通信(simultaneous wireless information and power transfer, SWIPT)技术实现基于无线射频信号的信息与能量传输,提出在基于无线射频网络中采用SWIPT技术的具有自能量回收的非分时全双工中继系统.该系统利用网络中多个可供电无线设备作为能量接入点(energy access point, EAP),能量受限的中继采用功率分配方案,实现信息传输、能量捕获和协作传输在1个时间块中同步进行.以最大化系统吞吐量作为优化目标,采用二次优化、半定松弛和变量消减等方法将原多变量非凸问题转换为半定规划问题,运用拉格朗日方法进行问题求解,通过联合优化中继发射功率、中继发射波束成形向量和功率分配比率,提高系统的性能增益.实验结果表明了所提出系统的吞吐量在解码转发(decode-and-forward, DF)协议下优于在放大转发(amplify-and-forward, AF)协议下;在中继从源节点捕获的能量有限时,通过增加EAP的数量来提高系统捕获的能量能有效提高系统运行速率;验证了与HD-SWIPT(half-duplex with SWIPT)和FD-no-SWIPT(full-duplex without SWIPT)中继系统相比,所提出的系统在提高系统性能方面具有更好的增益.

       

      Abstract: Adopting simultaneous wireless information and power transfer (SWIPT) technology to realize information and energy transmission based on radio frequency(RF) signals, a non-time-switching full-duplex relay system with SWIPT and self-energy recycling in radio frequency network is proposed. In this system, multiple idle wireless devices with energy are used as an additional energy access point (EAP), the energy-limited relay adopts the power splitting (PS) scheme, and information transmission, energy harvest and cooperative transmission are completed simultaneously in a slot. Taking maximize system throughput as an optimization target, the system transforms the original multivariate non-convex problem into a semi-definite programming problem by adopting quadratic optimization, semi-definite relaxation (SDR) and variable reduction methods, and utilizes Lagrange method to solve optimization problems. The system performance is improved by jointly optimizing the relay transmit power, the relay transmit beamforming vector and the power splitting ratio. Simulation experiments show that the throughput of the proposed system is better than the amplify-and-forward (AF) protocol under the decode-and-forward (DF) protocol. And when the energy harvested by the source node is limited, the stable and efficient operation of the system can be promoted by increasing the number of EAPs to increase the energy obtained by the system. Experimental results also verify that compared with half-duplex with SWIPT and full-duplex without SWIPT relay systems, the proposed system has more significant gains in improving system performance.

       

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