A Hybrid VLC/RF Cell-Free Massive MIMO System

Achieving high data rate is always a goal that could be met by developing new technologies and investigating potential ones. Recently, the concept of cell-free massive MIMO systems (CF-mMIMO) has been considered to enhance the performance of systems that operate merely with Radio Frequency (RF) or visible light communication (VLC) technologies. In this paper, a hybrid VLC/RF cell-free massive MIMO system is proposed where an RF cell-free network is used to support a VLC cell-free network. The idea is to utilize the benefits of each network and balance the load aiming at maximizing the system's sum-rate. The system is evaluated using zero-forcing (ZF) precoding scheme. A user association algorithm is proposed to assign users to either VLC or RF networks. Results show that the proposed algorithm outperforms a random network association of users. Results also show great potential for the proposed system compared to standalone cell-free networks.