In this study, power-domain non-orthogonal multiple access (NOMA) is combined with zero-forcing (ZF) vertical Bell Labs layered space-time (V-BLAST) technique. Motivated by the fact that the successive interference cancellation (SIC) is a pivotal element in either technique, we thoroughly investigate the impact of SIC on inter-user and inter-layer interference. A two-user downlink scenario is investigated where a multi-antenna base station with no instantaneous channel state information simultaneously communicates with two users each with multiple antennas. The average sum rate of the considered system is analytically derived in an exact form. Correspondingly, the power allocation value on each substream is optimized such that the average sum rate is maximized. We show that when the classical power-domain NOMA idea is incorporated into the ZF V-BLAST algorithm, the far user cannot completely cancel inter-layer interference. Nonetheless, the proposed approach turns out to yield an average sum rate performance near to that of a higher-complexity method based on maximum likelihood detection.

中文翻译：

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NOMA 带零迫 V-BLAST

在这项研究中，功率域非正交多址 (NOMA) 与迫零 (ZF) 垂直贝尔实验室分层时空 (V-BLAST) 技术相结合。受连续干扰消除 (SIC) 是这两种技术中的关键要素这一事实的启发，我们彻底研究了 SIC 对用户间和层间干扰的影响。研究了一个双用户下行链路场景，其中没有瞬时信道状态信息的多天线基站同时与两个用户通信，每个用户都有多个天线。所考虑系统的平均总和率以精确的形式通过分析推导出来。相应地，优化每个子流上的功率分配值，使得平均和速率最大化。我们表明，当经典的功率域 NOMA 思想被纳入 ZF V-BLAST 算法时，远用户不能完全消除层间干扰。尽管如此，所提出的方法结果表明产生的平均总和率性能接近基于最大似然检测的更高复杂性方法的平均总和率性能。