IRS-Assisted Aggregated VLC-RF System: Resource Allocation for Energy Efficiency Maximization

Intelligent reflecting surface (IRS) alters the wireless channel by dynamically adjusting the propagation of wireless signals, thereby having the ability to enhance communication performance. Due to its low power consumption, IRS is expected to play an important role in improving energy efficiency (EE). In this paper, both optical IRS (OIRS) and radio frequency (RF) IRS are employed to assist aggregated visible light communication (VLC)-RF systems, and then a resource allocation algorithm is proposed to improve EE. To this end, a model for the IRS-assisted aggregated VLC-RF system is first established, followed by the formulated EE maximization problem. Furthermore, the EE maximization problem is decomposed into four subproblems, focusing on RF IRS configuration, optical subchannel assignment, OIRS arrangement, and joint power allocation. By employing block coordinate descent (BCD), the four subproblems are solved iteratively. Moreover, simulation results show the significant EE improvement brought by the IRS for aggregated VLC-RF systems. In addition, the convergence and effectiveness of the proposed BCD-based resource allocation algorithm, as well as the influence of key system parameters on EE are also demonstrated.