RIS-NOMA-assisted short-packet communication with direct links

Abstract

Amidst the rapid evolution of next generation networks, meeting escalating demands for broad connectivity, minimal delay, and enhanced spectral efficiency is imperative. The fusion of reconfigurable intelligent surfaces (RIS) with non-orthogonal multiple access (NOMA) emerges as a promising approach to tackle these challenges. Our study zooms into the downlink setup, emphasizing short-packet communications (SPCs) and direct links. We concentrate on optimizing the performance of this RIS-NOMA fusion, meticulously deriving precise expressions for the average block error rate (ABLER) for near and far users. These ABLER metrics are pivotal for gauging system efficacy. A key focus of our inquiry lies in balancing blocklength and the number of RIS elements, vital for optimizing system performance. Our study underscores the intricate trade-offs involved and showcases the superiority of NOMA and RIS integration over conventional orthogonal multiple access (OMA) and RIS setups, especially in SPC scenarios. Our findings underscore both the challenges and a viable solution by leveraging the synergies between RIS and NOMA to boost network performance.