Medium-transparent Dynamic Bandwidth Allocation for 5G Fiber Wireless Dense Fronthaul Networks

Fifth generation (5G) networks are expected to combine several technologies to meet the ever-increasing capacity demands. Among them, centralized-radio access network (C- RAN) architecture, enables the separation of the baseband unit (BBU) from the remote radio head (RRH) so as to achieve higher performance in terms of cost-efficiency and flexibility. Another key 5G technology is the deployment of a massive number of multiple-input multiple-output (MIMO) antennas operating at higher frequencies, i.e., at the millimeter wave (mmWave) band. However, this move towards high mmWave traffic streams make the use of the traditional interface between BBU and RRH, its main specification being the common public radio interface (CPRI), prohibitive. To that end, a novel 5G fronthaul architecture is needed, able to cope with scenarios where high fronthaul traffic is expected, e.g., in dense area networks. To ensure high performance, an efficient medium access control (MAC) protocol should be also designed for these demanding use cases. To this end, a medium transparent MAC (MT-MAC) protocol was recently proposed for fiber wireless (FiWi) fronthaul networks. Although MT-MAC was shown to achieve high performance in terms of throughput and delay for indoor scenarios, its performance under challenging outdoor scenarios is unknown. Hence, in this paper, we study the MT- MAC performance under realistic outdoor dense area network conditions and we comment on its suitability as a 5G protocol solution for FiWi fronthaul networks. Finally, further insights are given for the key parameters that should be taken into account in the design of efficient 5G protocol solutions.