Efficient Mobile Fronthaul Incorporating VLC Links for Coordinated Densified Cells

We propose a hybrid optical spectral efficient mobile fronthaul (MFH) incorporating low-cost light-emitting diode-based visible light communication (VLC) links in the spatial densified network to enable multi-tier cell coordination. With proposed VLC links between multi-tier master remote radio heads (RRHs) and slave RRHs, fiber connection is not necessary for all RRHs, which simplifies the network structure, and reduces the deployment and operation cost. The proposed architecture can increase the flexibility and capability for network extension significantly by adding new RRHs without fiber deployment. Centralized and distributed pre-equalization are proposed and compared with the letter theoretically and experimentally. In the experiment, we demonstrated a MFH network serving one master RRH and six slave RRHs with only single fiber connection, delivering eight independent long term evolution (LTE) streams with multi-tier cell coordination. Experimental results verify the feasibility of the proposed scheme with high performances suitable for LTE and 64-quadratic-amplitude modulation (64-QAM).