This paper investigates a relay assisted simultaneous wireless information and power transfer (SWIPT) for downlink in cellular systems. Cooperative non-orthogonal multiple access (C-NOMA) is employed along with power splitting protocol to enable both energy harvesting (EH) and information processing (IP). A downlink model consists of a base station (BS) and two users is considered, in which the near user (NU) is selected as a relay to forward the received signal from the BS to the far user (FU). Maximum ratio combining is then employed at the FU to combine both the signals received from the BS and NU. Closed form expressions of outage propability, throughput, ergodic rate and energy efficiency (EE) are firstly derived for the SWIPT based C-NOMA considering both scenarios of with and without direct link between the BS and FU. The impacts of EH time, EH efficiency, power-splitting ratio, source data rate and distance between different nodes on the performance are then investigated. The simulation results show that the C-NOMA with direct link achieves an outperformed performance over C-NOMA without direct link. Moreover, the performance of C-NOMA with direct link is also higher than that for OMA. Specifically, (1) the outage probability for C-NOMA in both direct and relaying link cases is always lower than that for OMA. (2) the outage probability, throughput and ergodic rate vary according to \(\beta\), (3) the EE of both users can obtain in SNR range of from \(-10\) to 5 dB and it decreases linearly as SNR increases. Numerical results are provided to verify the findings.

本文研究了蜂窝系统中下行链路的中继辅助同时无线信息和功率传输（SWIPT）。协作式非正交多路访问（C-NOMA）与功率分配协议一起使用，以实现能量收集（EH）和信息处理（IP）。下行链路模型包括一个基站（BS）和两个用户，其中选择了近端用户（NU）作为中继，将接收到的信号从BS转发到远端用户（FU）。然后，在FU处采用最大比率合并以合并从BS和NU接收的两个信号。首先基于SWIPT的C-NOMA，考虑到BS和FU之间有直接链接的情况和没有直接链接的情况，首先得出了停机概率，吞吐量，遍历速率和能效（EE）的闭式表达式。EH时间的影响，然后研究了EH效率，功率分配比，源数据速率以及不同节点之间的距离对性能的影响。仿真结果表明，具有直接链接的C-NOMA的性能优于没有直接链接的C-NOMA。此外，具有直接链接的C-NOMA的性能也高于OMA。具体而言，（1）在直接链路和中继链路情况下，C-NOMA的中断概率始终低于OMA。（2）中断概率，吞吐量和遍历率根据 具有直接链接的C-NOMA的性能也高于OMA。具体而言，（1）在直接链路和中继链路情况下，C-NOMA的中断概率始终低于OMA。（2）中断概率，吞吐量和遍历率根据 具有直接链接的C-NOMA的性能也高于OMA。具体而言，（1）在直接链路和中继链路情况下，C-NOMA的中断概率始终低于OMA。（2）中断概率，吞吐量和遍历率根据\（\ beta \），（3）两个用户的EE都可以在SNR范围从\（-10 \）到5 dB时获得，并且随着SNR的增加线性降低。提供了数值结果以验证发现。