A 5G C-RAN Architecture for Hot-Spots: OFDM based Analog IFoF PHY and MAC Layer Design

Centralized Radio Access Network (C-RAN) comprises one of the main technologies for high capacity and low latency fronthauling in 5G networks. In this paper, we propose and evaluate an optical fronthaul 5G C-RAN architecture that targets to meet the bandwidth, latency and energy requirements of high traffic hot-spot areas. The proposed architecture employs Intermediate-Frequency-over-Fiber (IFoF) signal generation by Photonic Integrated Circuit (PIC) Wavelength Division Multiplexing (WDM) optical transmitters at the Base-Band Unit (BBU), while a novel design of Reconfigurable Optical Add-Drop Multiplexers (ROADMs) is used at the Remote Radio Head (RRH) site. An aggregate capacity up to 96 Gb/s has been reported by employing two WDM links with 4-band Orthogonal Frequency Division Multiplexing (OFDM) 64-QAM 0.5 Gbaud signals, showing error vector magnitude performance within the acceptable 8% limit. The physical layer evaluation of the proposed fronthaul is also extended with the evaluation of the network throughput and mean packet delay latency, using a Medium Transparent-Medium Access Control (MT-MAC) protocol, which employs gated service indicating latencies below 10ms.