Active RIS-Assisted CFm-MIMO with User Mobility and Constrained Fronthaul Capacity

In the ever-evolving landscape of next-generation wireless communication systems, the need for high data rates, seamless connectivity, and energy efficiency continues to increase. To meet these demands, the integration of emerging technologies such as cell-free massive multiple-input multiple-output (CFm-MIMO) and reconfigurable intelligent surfaces (RIS) has gained significant attention. This paper presents a comprehensive performance analysis of a downlink active RIS-assisted CFm-MIMO system in the context of user terminal (UT) mobility, emphasizing the critical aspect of constrained fronthaul capacity. The paper employs a rigorous analytical framework to determine the outage performance of the proposed system considering imperfections in the channel state information (CSI). The findings presented in this paper demonstrate the impact of the number of RIS elements ($N$), quantization parameters, UT mobility, scattering models, and imperfect CSI on the outage probability. It is revealed that by increasing the $N$ from 8 to 32 will significantly decreases the OP by 99.75%. Moreover, it is interesting to observe that the choice and optimization of quantization parameters remain consistent regardless of RIS presence.