The Fronthaul Infrastructure of 5G Mobile Networks

Abstract

The next wave of innovation will certainly generate numerous new opportunities for emerging technology solutions based on networking services and applications with stringent key performance indicators (KPIs) such as ultra-low 1 ms latency, a 1000 fold bandwidth increase, 99.99 % reliability and availability, which are immensely above those supported by current mobile networks. A new architecture of mobile networking called cloud radio access network (C-RAN) has been introduced over the last few years not only to supporting these indicators, but also to increasing scalability, manageability, and flexibility of mobile systems. In this context, this paper addresses the principal technology enablers and their features for C-RAN fronthaul architectures of the 5 th generation (5G) mobile networks, namely space-division multiplexing (SDM), massive multiple-input multiple-output (MIMO) signaling, analog radio-over-fiver (A-RoF), and millimeter wave (mmWave) frequency technology. These technologies pave the way towards a truly viable and efficient fronthaul infrastructure for 5G mobile communications with connectivity for thousands of users and strict latency control. In this fashion, we perceive a network infrastructure scenario with seamless starting and ending interfaces by exploiting space diversity in both radio frequency and optical domains with efficient integrated photonics technology-all combined with adaptive softwaredefined network programming, so as to satisfy the 5G KPIs. Furthermore, we address the most relevant features of these technologies as a potential guideline for potential fronthaul infrastructure deployment of next generation mobile networks.

The Integration of 5G, PON and VLC Technologies for Ubiquitous Connectivity in Autonomous and Cooperative Systems

“…While for the fronthaul the capacity of 25 Gb/s has to be ensured. Respectively, user data rates should reach 1 Gb/s for a few devices and 25 Mb/s for up to 30.000 users, highly concentrated in hot-spot areas like for example football stadiums [4]. Moreover, fronthaul requires very low latency [12].…”

“…In addition, the adoption of A-RoF avoids the need for high-speed analog to digital conversion and additional modulation/demodulation stages at the remote site, which is highly demanding in terms of energy consumption [19]. According to [4], A-RoF provides a much more beneficial functional split , larger bandwidth and significant cost savings thus becoming a natural candidate for the generation of mm-Wave signals [3], [4].…”

“…To ensure the maximal possible centralization and to simplify the ONt-X Box ensuring its cost-efficiency, we base our architecture on the generation of mm-Waves in the transmitter located in CO utilizing the baseband data. Several distinct methods of mm-Wave signal generation in A-RoF systems can be used as proposed in [4]. It allows transporting an intermediate frequency signal over the fiber, rather than the target RF frequency.…”

“…On the other hand, 5G technology still needs to satisfy stringent key performance indicators (KPIs) such as higher bandwidth and data-rate per user, increased number of connected devices, lower energy consumption, and reduced end-to-end latency [3]. Unlicensed or slightly licensed millimeter-wave (mm-Wave) frequency bands, including the K/Ka-band (24.25 -27.50 GHz) -the 5G NR n258, V-band region (~60 GHz), the W-band (75 -110 GHz), for radioover-fiber (RoF) link deployment are key candidates for 5G fronthaul networking as well as part of the solution to satisfying these KPIs [4], [5].…”

Analog Radio Over Fiber Fronthaul for High Bandwidth 5G Millimeter-Wave Carrier Aggregated OFDM

“…These networks will offer broadband connectivity to a very large number of end users with a guaranteed quality of service (QoS) [1]. It is expected by the 5G key performance indicators (KPIs) that the capacity of 5G networks will increase by 1000 times, offering data rates varying between 0.25 to 1 Gbit/s with a peak of 10 Gbit/s to end users concentrated in hot-spot areas, e.g., malls, universities and football stadiums [2]. Very reliable networks will be constructed with low latency.…”