Investigating Low Latency Communications With Link-Layer Rate of NOMA Under Nakagami-m Fading Channel in Finite Blocklength Regime

This paper investigates link-layer rate of two-user downlink non-orthogonal multiple access (NOMA) networks under Nakagami-m fading channel with short packet communications. The overall reliability of the NOMA users is based on transmission error probability and queuing delay violation probability. We use an effective capacity tool to find the reliability and latency of the two-user with short packet communications. We derive closed-form expressions for the achievable effective capacity of both near user and far user of downlink NOMA networks with short packet communications under Nakagami-m fading channel conditions. We investigate the impact of transmit signal-to-noise ratio, delay exponent, transmission error probability, and various blocklength on the achievable effective capacity of each user. The impact of varying packet sizes (blocklength) and transmit SNR on the total achievable EC of NOMA users are investigated in detail. We also perform Monte-Carlo simulations to validate our proposed closed-form expressions of two-user downlink NOMA.