Non-orthogonal multiple access (NOMA) in conjunction with finite blocklength (short packet) communications is regarded as an enabler for ultra-reliable and low-latency communications (URLLC). In this paper, we investigate the link-layer rate, i.e., the effective capacity, of a two-user NOMA in finite blocklength regime. The delay performance of the NOMA users is analyzed by taking into consideration the queueing delay violation probability and the transmission error probability. We further provide closed-form expressions for the individual effective capacity of the NOMA users in Rayleigh fading environment. Through simulations, we investigate the impact of the transmit signal-to-noise ratio and the delay exponent on the achievable effective capacity and the queueing delay violation probability of the NOMA weak and strong users. In particular, results show that when using short packet communications, the queueing delay violation probability cannot be improved below a threshold.

中文翻译：

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具有有限块长度的 NOMA 链路层速率，用于低延迟通信

非正交多址 (NOMA) 与有限块长度（短数据包）通信一起被视为超可靠和低延迟通信 (URLLC) 的推动者。在本文中，我们研究了链路层速率，即有限块长度机制中的双用户 NOMA 的有效容量。通过考虑排队时延违规概率和传输错误概率来分析NOMA用户的时延性能。我们进一步为 NOMA 用户在瑞利衰落环境中的个人有效容量提供了闭式表达式。通过仿真，我们研究了发射信噪比和延迟指数对 NOMA 弱用户和强用户可达到的有效容量和排队延迟违反概率的影响。特别是，