In this paper, we study the performance of reconfigurable intelligent surfaces (RISs) in a multicell broadcast channel (BC) that employs improper Gaussian signaling (IGS) jointly with non-orthogonal multiple access (NOMA) to optimize either the minimum-weighted rate or the energy efficiency (EE) of the network. We show that although the RIS can significantly improve the system performance, it cannot mitigate interference completely, so we have to employ other interference-management techniques to further improve performance. We show that the proposed NOMA-based IGS scheme can substantially outperform proper Gaussian signaling (PGS) and IGS schemes that treat interference as noise (TIN) in particular when the number of users per cell is larger than the number of base station (BS) antennas (referred to as overloaded networks). In other words, IGS and NOMA complement to each other as interference management techniques in multicell RIS-assisted BCs. Furthermore, we consider three different feasibility sets for the RIS components showing that even a RIS with a small number of elements provides considerable gains for all the feasibility sets.
翻译:在本文中,我们研究了多细胞广播频道(BC)中可重新配置的智能表面(RIS)的性能,该频道使用不适当的高斯信号(IGS)与非垂直多重访问(NOMA)联合使用不适当的高斯信号(IGS),以优化网络的最低加权率或能源效率(EE),我们表明,虽然RIS可以显著改善系统性能,但无法完全减少干扰,因此我们必须使用其他干扰管理技术来进一步改进性能。我们表明,拟议的以NOMA为基础的IGS系统可以大大超过适当的高斯信号(GGS)和IGS系统,特别是当每个电池的用户数量大于基站天线(称为超载网络)时,将干扰作为噪音(TIN)处理。换句话说,IGS和NOMA作为多细胞RIS协助的公分卡的干扰管理技术相互补充。此外,我们认为,对于RIS组件的三种不同的可行性,表明即使具有少量要素的RIS也为所有可行性数据集带来相当大的收益。