In this paper, we propose simultaneous transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) assisted non-orthogonal multiple access (NOMA) networks. The considered STAR-RIS utilizes the mode switching (MS) protocol to serve multiple NOMA users located on both sides of the RIS surface. Based on the MS protocol, each STAR-RIS element can operate in full transmission or reflection mode. Within this perspective, we propose a novel algorithm to partition the STAR-RIS surface among the available users. This algorithm aims to determine the proper number of transmitting/reflecting elements needs to be assigned to each user in order to maximize the system sum-rate while guaranteeing the quality-of-service requirements for individual users. For the proposed system, we derive closed-form analytical expressions for the outage probability (OP) and its corresponding asymptotic behavior under different user deployments. Finally, Monte Carlo simulations are performed in order to verify the correctness of the theoretical analysis. It is shown that the proposed system outperforms the classical NOMA and orthogonal multiple access systems in terms of OP and sum-rate.
翻译:在本文中,我们提议同时传送和反映可重新配置的智能表面(STAR-RIS)辅助的非横向多重访问(NOMA)网络。考虑的STAR-RIS利用模式转换协议为位于RIS表面两侧的多个NOMA用户服务。根据MS协议,每个STAR-RIS元素都可以以完全传输或反射的方式运作。从这个角度出发,我们提议一种新颖的算法,在现有用户之间分割STAR-RIS表面。这一算法的目的是确定向每个用户分配传送/反射元素的适当数量,以便最大限度地提高系统总和率,同时保证个人用户的服务质量要求。关于拟议的系统,我们为外差概率及其在不同用户部署下的相应症状行为制作了闭式分析表达方式。最后,对蒙特卡洛进行了模拟,以核实理论分析的正确性。它表明,拟议的系统在OP和Sum-raterate中优于典型的NOMA和正式多重访问系统。