Block Error Rate Minimization of Downlink MIMO‐NOMA With Finite Blocklength

ABSTRACT As a promising technology for 6G networks, non‐orthogonal multiple access (NOMA) can improve spectral efficiency by sharing the same time‐frequency resource of multiple users. However, most existing NOMA schemes assume infinite blocklength, leading to suboptimal performance in practical finite blocklength scenarios. This paper investigates the downlink multiple‐input multiple‐output (MIMO)‐NOMA transmission with finite blocklength (FBL). Our aim is to achieve the minimum average block error rate (BLER) by designing the precoding and detection vectors capable of eliminating inter‐cluster interference. An efficient power, rate, and blocklength allocation scheme, with the power allocation in waterfilling form and the rate and blocklength allocation in closed form is proposed here. Simulation results demonstrate the superiority of our proposed design.