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This work considers a multiple-input multiple-output (MIMO) non-orthogonal multiple access (NOMA) dual-hop relay system in which the size of signal packets is finite and the propagation environment follows the Nakagami-m distribution. Based on an approximation of the Gaussian Q-function, Riemann integral, and incomplete Gamma function, we derive the closed-form expressions of the block error rate (BLER), age of information (AoI), and latency of the proposed system in both exact and asymptotic cases. On the other hand, the automatic repeat request (ARQ) protocol and acknowledgment (ACK) are applied to confirm the accuracy of the receiving data packet process. Moreover, the maximal-ratio transmission (MRT), and maximal-ratio combining (MRC) are used to improve the BLER, AoI, and latency of the proposed system. The accuracy of mathematical analysis frameworks is confirmed by simulation results. The calculation results show that the considered system satisfies the requirement of ultra-reliable and low-latency communications (URLLC). The results also represent that the MIMO-NOMA system outperforms the MIMO-OMA system in terms of BLER performance. The results also provide insight into the optimizations of the power allocation coefficient and the number of transmission bits that minimize the BLER and AoI of the considered system. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we propose and analyze a downlink non-orthogonal multiple access (NOMA) relay system with full-duplex transmission model and decode-and-forward (DF) scheme. We assume that the source and the destination nodes have fixed power, whereas relay nodes have constrained energies and should harvest radio frequency (RF) energy from the source for operation power. The outage performance of this system is analyzed over the Nakagami- m fading channel, full-duplex transmission protocol and imperfect channel state information (CSI), and then the duration of energy harvesting in every block time, α T , is optimized to achieve the maximal throughput. Furthermore, the closed-form of outage probabilities and the fraction α are derived and evaluated in several scenarios. Moreover, the optimal power allocation coefficients that achieve the minimal outage probability while keeping the fairness in outage performance of end users are discussed. The analytical results are verified by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]