In this paper, we propose a simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) and energy buffer aided multiple-input single-output (MISO) simultaneous wireless information and power transfer (SWIPT) non-orthogonal multiple access (NOMA) system, which consists of a STAR-RIS, an access point (AP), and reflection users and transmission users with energy buffers. In the proposed system, the multi-antenna AP can transmit information and energy to several single-antenna reflection and transmission users simultaneously by the NOMA fashion in the downlink, where the power transfer and information transmission states of the users are modeled using Markov chains. The reflection and transmission users harvest and store the energy in energy buffers as additional power supplies, which are partially utilized for uplink information transmission. The power outage probability, information outage probability, sum throughput, and joint outage probability closed-form expressions of the proposed system are derived over Nakagami-m fading channels, which are validated via simulations. Results demonstrate that the proposed system achieves better performance as compared to the proposed system with discrete phase shifts, the STAR-RIS aided MISO SWIPT-NOMA buffer-less, conventional RIS and energy buffer aided MISO SWIPT-NOMA, and STAR-RIS and energy buffer aided MISO SWIPT-time-division multiple access (TDMA) systems. Furthermore, a particle swarm optimization-based power allocation (PSO-PA) algorithm is designed to maximize the uplink sum throughput with a constraint on the uplink joint outage probability and Jain's fairness index (JFI). Simulation results illustrate that the proposed PSO-PA algorithm can achieve an improved sum throughput performance of the proposed system.

翻译：本文提出了一种同时透射反射可重构智能表面与能量缓冲辅助的多输入单输出无线携能通信非正交多址系统，该系统由一个STAR-RIS、一个接入点以及配备能量缓冲的反射用户与透射用户构成。在所提系统中，多天线接入点在下行链路中可通过NOMA方式同时向多个单天线反射用户与透射用户传输信息与能量，其中用户的能量传输与信息传输状态采用马尔可夫链建模。反射用户与透射用户将收集的能量存储于能量缓冲器中作为辅助电源，并部分用于上行链路信息传输。在Nakagami-m衰落信道下，推导了所提系统的功率中断概率、信息中断概率、总吞吐量及联合中断概率的闭合表达式，并通过仿真验证。结果表明，与离散相位偏移的所提系统、STAR-RIS辅助的无缓冲MISO SWIPT-NOMA系统、传统RIS与能量缓冲辅助的MISO SWIPT-NOMA系统以及STAR-RIS与能量缓冲辅助的MISO SWIPT-TDMA系统相比，所提系统能获得更优的性能。此外，设计了一种基于粒子群优化的功率分配算法，在约束上行链路联合中断概率与Jain公平性指数的条件下最大化上行链路总吞吐量。仿真结果表明，所提PSO-PA算法能有效提升系统的总吞吐量性能。