This paper investigates the cell-edge user’s performance in a two-user multiple-input single-output non-orthogonal multiple access (MISO-NOMA) systems using downlink beamformers for optimal power allocation. In particular, power allocation coefficients (PACs) are adjusted through beamformers so that the cell-edge user’s performance is improved in a two-user network scenario. In the proposed model, a cell-center user with strong channel conditions plays a role as an energy harvesting (EH) relay by using simultaneous wireless information and power transfer (SWIPT) protocol to assist the cell-edge user having weak channel conditions. Initially, we formulate the expressions for signal-to-interference-plus-noise ratio (SINR) at the cell-center user and signal-to-noise ratio (SNR) and SINR at the cell-edge user in terms of an indefinite quadratic form (IQF) whilst considering distinct correlation matrices for each link. Next, we achieve exact and approximate closed-form expressions for outage probability of linearly dependent and of distinct beamformers, respectively by using IQF approach. The proposed model achieves diversity gain whereas the analytical expressions are validated by simulation means.

本文研究了使用下行​​波束形成器优化功率分配的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。特别是，功率分配系数（PAC）通过波束形成器进行调整，从而在两用户网络情况下提高了小区边缘用户的性能。在提出的模型中，具有强大信道条件的小区中心用户通过使用同时无线信息和功率传输（SWIPT）协议来协助具有弱信道条件的小区边缘用户，充当能量收集（EH）中继的角色。原来，我们以不确定的二次形式来表示信元中心用户的信干噪比（SINR）和信元边缘用户的信噪比（SNR）和SINR的表达式（ （IQF），同时为每个链接考虑不同的相关矩阵。接下来，我们分别使用IQF方法获得线性相关和不同波束形成器的中断概率的精确和近似闭式表达式。提出的模型实现了分集增益，而解析表达式通过仿真手段得到了验证。