RSMA-Aided Full-Duplex Networks Under Imperfect CSI and SIC: Performance Evaluation

TL;DR

This paper evaluates the performance of a full-duplex RSMA system considering practical issues like imperfect CSI and SIC, deriving analytical expressions and validating them through simulations.

Contribution

It provides the first closed-form performance analysis of RSMA full-duplex systems under realistic imperfections like CCI, SI, and CSI errors.

Findings

Imperfect CSI impacts performance more at low transmit power.

Imperfect SIC causes severe degradation at high transmit power.

Ignoring CCI and assuming perfect SI overestimates system performance.

Abstract

This work investigates a full-duplex (FD)-enhanced Rate-Splitting Multiple Access (RSMA) system under practical constraints, including imperfect channel state information (CSI) and successive interference cancellation (SIC). We derive closed-form expressions for key performance metrics, such as outage probability and throughput, for both uplink and downlink users. The analysis considers co-channel interference (CCI) from uplink to downlink users and models the self-interference (SI) channel as a random variable. Monte Carlo simulations validate the analytical results and highlight the impact of system imperfections on RSMA-FD performance. At low transmit power, imperfect CSI significantly affects the system, though this effect weakens as power increases. In contrast, imperfect SIC becomes more detrimental at high transmit power, causing severe degradation. Additionally, neglecting CCI and assuming perfect SI cancellation leads to substantial overestimation of performance. Lastly, we demonstrate that the SI cancellation factor must be carefully selected to suppress interference effectively. Otherwise, a poor choice limits the full potential of FD technology.