Improving the Performance of Cell-Edge Users in MISO-NOMA Systems Using TAS and SWIPT-Based Cooperative Transmissions
Improving the Performance of Cell-Edge Users in MISO-NOMA Systems Using TAS and SWIPT-Based Cooperative Transmissions
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DOI：
10.1109/tgcn.2017.2777510
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发表时间：
2018-03
影响因子：
4.8
通讯作者：
Tri Nhu Do;D. B. da Costa;T. Duong;Beongku An
中科院分区：
文献类型：
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作者：
Tri Nhu Do;D. B. da Costa;T. Duong;Beongku An
本文研究了两用户多输入单输出非正交多址（MISO-NOMA）系统中小区边缘用户的性能。由于中断性能和小区边缘用户的公平数据速率是NOMA系统中的关键问题，我们专注于如何解决这些问题。为此，我们提出了三个合作的下行链路传输方案，利用混合同步无线信息和功率传输（SWIPT）和发射天线选择（TAS）协议。特别地，在每种方案中，小区中心用户充当中继以辅助小区边缘用户，并且其中继操作由混合时间切换/功率分配SWIPT协议供电。另外，每种方案采用不同的TAS准则来利用多天线基站的空间分集增益。特别是，我们推导出紧密的封闭形式的近似表达式的中断概率（OP）和相应的渐近OP提供显着的见解，我们提出的计划对系统性能的影响。我们的数值结果表明，所提出的方案相比，正交多址和非合作NOMA系统的性能可实现的改善。此外，所提出的方案实现不同程度的分集增益伴随着不同的复杂度要求。
In this paper, we study the performance of a cell-edge user in a two-user multiple-input single-output non-orthogonal multiple access (MISO-NOMA) system. Since the outage performance and fairness data rate of cell-edge users are essential issues in NOMA systems, we focus on how to resolve such problems. To this end, we propose three cooperative downlink transmission schemes utilizing hybrid simultaneous wireless information and power transfer (SWIPT) and transmit antenna selection (TAS) protocols. Particularly, in each scheme, a cell-center user acts as a relay to assist the cell-edge user and its relaying operation is powered by a hybrid time-switching/power-splitting SWIPT protocol. Additionally, each scheme employs a different TAS criterion to exploit the spatial diversity gain of a multiple antennas base station. In particular, we derive tight closed-form approximate expressions for the outage probabilities (OPs) and the corresponding asymptotic OPs to provide significant insights into the impact of our proposed schemes on the system performance. Our numerical results demonstrate the achievable performance improvements of the proposed schemes in comparison to that of the orthogonal multiple access and non-cooperative NOMA systems. In addition, the proposed schemes achieve various level of diversity gains accompanying with different complexity requirements.