arXiv:2611.14055v1 Announce Type: new Abstract: Future generations of wireless networks will support massive communication and hyper-reliable low-latency communications, which are fundamental to large-scale Internet of Things (IoT) deployments with stringent performance requirements. To support such diverse and demanding requirements, robust and flexible multiple access schemes are essential. In this work, we develop a comprehensive analytical framework for evaluating uplink rate-splitting multiple access (RSMA) in the finite blocklength regime under realistic non-ideal conditions. Specifically, we derive closed-form expressions for the block error rate (BLER) and goodput, accounting for imperfect channel state information at the receiver (CSIR), imperfect successive interference cancellation (SIC), and hardware impairments. To reflect practical wireless environments, we model the channel using Nakagami-m fading model. Our analysis shows that at lower transmit power levels, imperfect CSIR is the dominant performance-limiting factor, whereas hardware impairments and imperfect SIC become more significant in degrading system performance as the transmit power increases. To further understand the system behavior, we derive asymptotic BLER expressions. We also analyze the impact of rate allocation, demonstrating its critical role in ensuring fairness and reliability. Monte Carlo simulations validate our analytical expressions. Notably, our results show that uplink RSMA significantly outperforms NOMA even when RSMA operates under harsh imperfect CSIR. This superiority establishes RSMA as a robust and efficient candidate for future wireless networks in practical, constrained environments