基于SWIPT-TS的被困用户双向传输时间分配算法

本文针对灾难场景下被困用户因移动终端无法充电而与外界中断通信的问题，提出了一种基于SWIPT能量采集的被困用户中继协作传输方法。该中继系统中被困用户为源节点，周围的邻近用户随机地分布在其与基站之间并且作为其与基站进行通信的中继节点，并采用SWIPT-TS方式为被困用户充电。在被困用户采集的能量和系统下行速率的约束下，建立了系统上行可达速率最大的优化问题，通过分析两跳传输的对偶性以及利用Lambert W函数，提出了一种基于系统上行可达速率最大化的中继选择和时间分配算法。本文所提的算法的解是闭式型，因此复杂度较低。仿真结果表明，本文所提的基于系统上行可达速率最大化的中继选择和时间分配算法不仅可以为被困用户提供能量，还可以提高系统数据传输速率。 

Two-Ways Transmission Time Allocation Algorithm for Trapped User Based on SWIPT-TS

? ?This paper proposes a relay cooperative transmission method for trapped user based on SWIPT energy harvesting to solve the problem of communication interruption between trapped user and the outside world due to mobile terminal cannot be charged in disaster scenarios. In the relay system， the trapped user is the source node， and the neighboring user terminals are randomly distributed between it and the base station and serve as relay nodes to assist the trapped user to communicate with the base station. In addition， SWIPT-TS method is adopted to charge the trapped users. Under the constraints of harvested energy by trapped user and system downlink rate， the optimization problem of maximum uplink available rate is established. By analyzing the duality of two-hop transmission and using Lambert W function， a relay selection and time allocation algorithm based on maximum uplink available rate is proposed. The solution of the algorithm proposed in this paper is closed-form， so the complexity is low. Simulation results show that the proposed relay selection and time allocation algorithm in this paper can provide energy for trapped user and improve data transmission rate.