Fronthaul in 5G Transport Networks: IEEE1914.1 Architecture and Requirements

The deployment of 5G New Radio (NR) implies the capability both to deliver new mobile services (eMBB, URLLC, mMTC) and to perform critical functions as massive MIMO, beamforming, carrier aggregation, CoMP and scalable centralized/virtualized radio access network (C-RAN/V-RAN). In order to ease the implementation of such services and functions 3GPP specifies, from Release 14 onwards, functional split options for the baseband station processing chain, resulting in a separation between “distributed units” (DUs), located at cell sites, and Centralized Units (CUs), implementing the higher layer processing chain of several baseband units. Moving from 3GPP network view, the newly published IEEE Std 1914.1 specifies: •Architecture for the transport of mobile fronthaul traffic over packet-based networks (e.g. Ethernet). •Requirements and definitions for the fronthaul networks, including data rates, synchronization, and quality of service (QoS) for user data traffic, management and control plane traffic. •Network slicing application models of fronthaul networks (“per QoS” and “per transport user”). In this paper we recap the basics of the new standard and focus on the fact that the relevant recommendations can be easily extended to any transport solution even if “not packet-based”. Despite backhaul is out of the scope of the project, useful indications can be derived also for backhaul applications sharing same infrastructure with fronthaul. In this sense, the new standard can be used as a general reference for the design and the analysis of carrier grade transport networks devoted to mobile cross-hauling applications.