A. Mesodiakaki 1[0000−0001−9309−0524] , P. Maniotis 1 , G.Abstract. Next generation, i.e., fifth generation (5G), networks will leverage both fiber and wireless (FiWi) technology to meet the challenging 5G traffic demands. Moreover, a Cloud-Radio Access Network (C-RAN) architecture will be mainly adopted, which places the BaseBand Units (BBUs) at centralized locations, thus offering cost-efficient energy supply and climate control. To this end, efficient Medium Transparent-Medium Access Control (MT-MAC) protocols are needed to ensure the optimal exploitation of both media. In this paper, we propose a gated service MT-MAC protocol (gMT-MAC) for Millimeter Wave (mmWave) Analog Radio-over-Fiber (A-RoF) C-RANs. GMT-MAC grants a transmission window to each user equal to the time needed for its requested traffic to be successfully sent. A mean packet delay model is also proposed and verified by means of simulation. The performance of gMT-MAC is evaluated for different network load conditions, number of Remote Radio Heads (RRHs) and optical availability values. The provided results prove the suitability of gMT-MAC to meet the sub-ms delay requirements of latency-critical 5G services.Keywords: Fifth Generation (5G) networks · mean packet delay model · fiber-wireless (FiWi) · millimeter wave (mmWave) · cloud-radio access networks (C-RANs) · analog radio-over-fiber (A-RoF) · medium transparent-MAC (MT-MAC).