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The use of millimeter-wave (mm-wave) frequencies is required in order to support the increasing number of connected devices expected from the fifth generation (5G) of mobile communications. Subsequently, the generation of radio-frequency (RF) carriers ranging from 10 GHz to 300 GHz and their transport through optical distribution network (ODN) is a key element of the future 5G fronthaul. Optically assisted RF carrier generation is one of the most promising solutions to tackle this issue, allowing a wide use of analog radio-over-fiber (ARoF) architectures. However the main limitation of these optical methods is related to the finite coherence of lasers sources, which can dramatically degrade data transmission in analog formats. To mitigate its impact, the use of orthogonal frequency-division multiplexing (OFDM) as the 5G standard allows employing efficient phase noise compensation algorithms. Therefore, in this study, we present an experimental demonstration of a mm-wave generation technique based on an optical phase-locked loop (OPLL) that fulfills the frequency specifications for 5G. Then, an algorithm is introduced that improves data recovery at reception and reduces the impact of a possible high phase noise carrier. Finally, a back-to-back data transmission experiment is performed, demonstrating the efficiency of the algorithm to reach the 5G requirements. These results emphasize the use of OPLLs as a viable solution to generate mm-wave carriers for 5G and beyond.

Fifth-generation mobile networks (5G) is the established solution to satisfy the highly demanding key performance indicators such as traffic volumes, bit-rate, latency, and power consumption, among others of the future telecommunication infrastructure. The already saturated sub-6 GHz spectral band does not accommodate such requirements and forces the move towards higher frequencies, with the millimeter-wave (mm-wave) domain being an adequate band to operate. However, the exploitation of mm-wave signals in the mobile cells implies the deployment of an enormous quantity of small cells with associated equipment, footprint, and control. Thus, analog radio-over-fiber (ARoF) emerges as a suitable technology because of their attractive benefits such as low latency, low hardware complexity, and reduced power consumption. However, through investigation of experimental ARoF systems adhering to the 5G standard is scarce. Therefore, in this work, a novel and efficient bidirectional ARoF scheme based on multicore fiber (MCF) and oriented to 5G mm-wave communications is proposed and experimentally validated. The setup configurations are according to the 5G standard, enabling a wireless link at 26 GHz (n258, K-band) and time division duplex (TDD) communication. The proposed scheme is thoroughly evaluated under all the 5G numerologies and with different bandwidth settings. Moreover, key design considerations of the experimental testbed are explained and discussed to optimize the final yields of the system. The experimental results of both transmission directions are compared and analyzed, and prove the viability of the proposed bidirectional ARoF system as an excellent solution to be part of the future 5G mm-wave network.

[EN] The sixth generation (6G) mobile systems will create new markets, services, and industries making possible a plethora of new opportunities and solutions. Commercially successful rollouts will involve scaling enabling technologies, such as cloud radio access networks, virtualization, and artificial intelligence. This paper addresses the principal technologies in the transition towards next generation mobile networks. The convergence of 6G key-performance indicators along with evaluation methodologies and use cases are also addressed. Free-space optics, Terahertz systems, photonic integrated circuits, softwarization, massive multiple-input multiple-output signaling, and multi-core fibers, are among the technologies identified and discussed. Finally, some of these technologies are showcased in an experimental demonstration of a mobile fronthaul system based on millimeter 5G NR OFDM signaling compliant with 3GPP Rel. 15. The signals are generated by a bespoke 5G baseband unit and transmitted through both a 10 km prototype multi-core fiber and 4 m wireless V-band link using a pair of directional 60 GHz antennas with 10 degrees beamwidth. Results shown that the 5G and beyond fronthaul system can successfully transmit signals with both wide bandwidth (up to 800 MHz) and fully centralized signal processing. As a result, this system can support large capacity and accommodate several simultaneous users as a key candidate for next generation mobile networks. Thus, these technologies will be needed for fully integrated, heterogeneous solutions to benefit from hardware commoditization and softwarization. They will ensure the ultimate user experience, while also anticipating the quality-of-service demands that future applications and services will put on 6G networks., This work was partially funded by the blueSPACE and 5G-PHOS 5G-PPP phase 2 projects, which have received funding from the European Union's Horizon 2020 programme under Grant Agreements Number 762055 and 761989. D. PerezGalacho acknowledges the funding of the Spanish Science Ministry through the Juan de la Cierva programme.

Fifth-generation mobile networks (5G) are the solution for the demanding mobile traffic requirements, providing technologies that fulfill the requisites of different type of services. The utilization of the millimeter-wave (mm-wave) band is the straightforward technique to achieve high bit rates. Moreover, analog radio-over-fiber (ARoF) brings outstanding benefits such as low cost, low power consumption, and high spectral efficiency, among others. Thereby, mm-wave ARoF is a strong candidate to pave the way for common public radio interface (CPRI) in the fronthaul for the future 5G architecture. As orthogonal frequency-division multiplexing (OFDM) is the adopted waveform in the 5G standard, it should be also utilized in mm-wave ARoF systems for 5G. However, phase noise is one of the most degrading factors in mm-wave OFDM ARoF systems. Therefore, in this work, an analysis of the phase noise is carried out through an experimental setup up. The configuration of this setup enables to gradually modify the final phase noise level of the system. Furthermore, an original and novel algorithm to compensate the phase noise in OFDM receivers is proposed. The performance of this algorithm is experimentally evaluated through the setup for different phase noise levels and different subcarrier spacings. The obtained results show the effectiveness of the proposed algorithm under those conditions, highlighting the viability of mm-wave OFDM ARoF for 5G and beyond.

This article presents an experimental demonstration of a high-capacity millimeter-wave 5G NR signal transmission with analog radio-over-fiber (ARoF) fronthaul over multi-core fiber and full real-time processing. The demonstration validates the core of the blueSPACE fronthaul architecture which combines ARoF fronthaul with space division multiplexing in the optical distribution network to alleviate the fronthaul capacity bottleneck and maintain a centralized radio access network with fully centralized signal processing. The introduction of optical beamforming in the blueSPACE architecture brings true multi-beam transmission and enables full spatial control over the RF signal. The proposed ARoF architecture features a transmitter that generates the ARoF signal and an optical signal carrying a reference local oscillator employed for downconversion at the remote unit from a single RF reference at the central office. A space division multiplexing based radio access network with multi-core fibre allows parallel transport of the uplink ARoF signal and reference local oscillator at the same wavelength over separate cores. A complete description of the real-time signal processing and experimental setup is provided and system performance is evaluated. Transmission of an 800 MHz wide extended 5G NR fronthaul signal over a 7-core fibre is shown with full real-time signal processing, achieving 1.4 Gbit/s with a bit error rate $$ < 3.8 × 10 - 3 and thus below the limit for hard-decision forward error correction with 7% overhead.

Analog radio-over-fiber (ARoF) technology has proven to be a promising solution to be part of the future millimeter-wave (mm-wave) 5G/6G architecture due to its attractive benefits such as simplified remote antenna units (RAUs), low-power consumption, and low cost. However, ARoF channels present hefty drawbacks, such as phase noise and nonlinear effects, that need to be addressed. The probabilistic amplitude shaping (PAS) technique is able to reduce the impact of such drawbacks, allowing a fine optimization of channel capacity usage. In particular, enumerative sphere shaping (ESS) implementation stands out as an excellent PAS approach because of its energy-efficiency and low complexity for short blocklengths. In this work, for the first time to the best of our knowledge, an ESS scheme is evaluated in an experimental bidirectional mm-wave ARoF setup oriented towards 5G communications. Furthermore, a novel soft ESS demapping algorithm is proposed and explained. The experimental results confirm the ESS technique, together with the proposed algorithm, as a convenient solution to enhance the channel capacity use of mm-wave ARoF systems for the 5G/6G fronthaul.

A V-band Vivaldi antenna design for beyond-5G base station applications operating within V-band is demonstrated. The device can be used for interfacing with radio-over-fibre links and optoelectronic components through a coplanar waveguide to slotline transition. Simulations show an end-fire radiation with a 3 dB gain bandwidth ranging between 46.9-77.4 GHz combined with the reflection coefficients remaining below-10dB for the same frequency range. A comb structure inspired by optical grating couplers is added providing an increased maximum gain of 12.6 dBi at 68.5 GHz. Measurement results validate the promising characteristics of the planar antenna.

In this work we present, analyze, and demonstrate an efficient bidirectional ARoF system for K-band 5G fronthaul based on multicore fiber. As the 5G standard establishes, the experimental testbed is configured regarding the time division duplex scheduling and tested by transmitting OFDM signals. Furthermore, the configuration of the setup enables the reusability of several components for both directions, allowing the reduction of the power consumption, complexity, and cost of the system. The bidirectional testbed is experimentally evaluated under different bandwidth configurations and power levels, achieving a maximum throughput of 4Gbit/s over 9m of wireless link. The experimental results prove and validate the proposed bidirectional ARoF scheme as a promising solution for the future mm-Wave 5G fronthaul.

This paper presents a beyond 5G fronthaul network with dynamic beamforming and -steering. The proposed fronthaul solution deploys optical beamforming (OBF) by combining space division multiplexing (SDM), analogue radio-over-fiber (ARoF), and the novel optical beam forming network (OBFN) technologies. From the service management and orchestration (MANO) point of view, the proposed fronthaul solution also deploys an advanced software defined networking (SDN) and Network Function Virtualization (NFV) control and orchestration architecture developed with the goal to optimally manage and reconfigure the physical layer resources (i.e., optical and radio) at the central office and cell sites (i.e., pool of baseband units (BBUs), remote radio heads (RRHs), ARoF transceivers and OBFNs). The proposed beyond 5G fronthaul architecture is primarily oriented to deploy massive machine-type communication (mMTC) services with high-bandwidth requirements, such as for industry 4.0. In this paper we experimentally validate the novel OBFN system, and the dynamic SDN/NFV MANO of the transport connectivity and network services for optical beamforming. The obtained experimental results show that the overall delay for the provisioning and removal of an OBF service, considering the contribution of the involved optical and radio systems and the SDN/NFV MANO layer, is 134s and 18s respectively. The reconfiguration of the OBF service to add or remove a beam can be performed in the range of 65–87s.

We evaluate the impact of Power-over-Fiber (PoF) technology on the fronthaul of a 5G-NR network with an Analog-Radio-over-Fiber at 25.5 GHz on a 10 km long multicore fiber. The study in this Letter analyzes the bit error rate (BER) performance for different levels of energy transmitted by the PoF system. 133 mW of maximum optical power at reception is demonstrated showing negligible BER impact or data transmission BER improvement in a dedicated and shared scenario. Comunidad de Madrid (Y2018/EMT-4892); Ministerio de Ciencia, Innovación y Universidades (RTI2018-094669-B-C32); Horizon 2020 Framework Programme (762055).

The introduction of 5G mobile networks, bringing multi-Gbit/s user data rates and reduced latency, opens new opportunities for media generation, transport and distribution, as well as for new immersive media applications. The expected use of millimeter-wave carriers and the strong network densification resulting from a much reduced cell size--which enable the expected performance of 5G--pose major challenges to the fronthaul network. Space division multiplexing (SDM) in the optical domain has been suggested for ultra-high capacity fronthaul networks that naturally support different classes of fronthaul traffic and further enable the use of analog radio-over-fiber and advanced technologies, such as optical beamforming. This paper discusses the introduction of SDM with multi-core fibers in the fronthaul network as suggested by the blueSPACE project, regarding both digitized and analog radio-over-fiber fronthaul transport as well as the introduction of optical beamforming for high-capacity millimeter-wave radio access. Analog and digitized radio-over-fiber are discussed in a scenario featuring parallel fronthaul for different radio access technologies, showcasing their differences and potential when combined with SDM.

This work studies and experimentally evaluates the performance enhancement by using PS-OFDM in a 5G mm-Wave ARoF system at 25 GHz for all 5G numerologies and with different phase noise levels.

A real-time millimeter wave radio-over-fiber link is experimentally demonstrated transmitting up to 1.4 Gbit/s 5G OFDM signals through a multi-core fiber to an 8 × 4 antenna array employing analog beamforming to radially track a moving receiver.

The sixth generation (6G) mobile systems will be the ultimate technology to support any networking requirement. 6G along with fog computing mobile nodes can support any application and use case within the supply chain delivery, regardless of the systems of systems complexity. In this paper, a holistic end-to-end framework platform based on the integration and leverage of 6G and fog mobile systems for physically-entangled systems is proposed. The framework platform, which relies on 6G fog enabled-delivery drones, terahertz communication, and artificial intelligence technologies, is described. The framework can be applied for highly cooperative, autonomous, and dynamic applications and systems such as supply chain’s last mile delivery of goods, harbour cranes, and maritime ports to help increasing access to goods in general, reduce traffic congestion and energy comsumption, and ease CO2 emissions from transportation. The proposed framework paves the way towards next generation supply chain management including last mile delivery.

[EN] We experimentally demonstrate a 5G digital fronthaul network that relies on multi-adaptive bandwidth/bitrate variable transceivers (BVTs) and an autonomic software-defined networking (SDN) control system for partially-disaggregated wavelength division multiplexing (WDM)/space division multiplexing (SDM). Transmission of 256-QAM 760.32 MHz orthogonal frequency-division multiplexing (OFDM) radio signal is performed, with a total radio transmission capacity of 5.667 Gb/s. Digitized signal samples are carried as a 22.25 Gb/s digitized radio-over-fiber (DRoF) data stream and transmitted over a WDM/SDM infrastructure including 40-wavelength 100-GHz arrayed waveguide gratings (AWGs) and 19-core fiber. The autonomic SDN controller deploys a control loop for the multi-adaptive OFDM-based BVTs that monitors the per-subcarrier signal to noise ratio (SNR) and assigns the optimal constellation based on the actual signal degradation. An error vector magnitude (EVM) below the targeted 2.1% is achieved while setting up connections in less than 5 s., This work was supported in part by the EC H2020 BLUESPACE Project under Grant 762055 and in part by the Spanish MICINN AURORAS Project under Grant RTI2018-099178.

This paper presents and experimentally validates an SDN/NFV architecture for the management of optical beamforming connectivity and network services for beyond 5G fronthaul, controlling OBFN coherent and incoherent systems, ARoF transceivers, BBUs with analog output/input and RRHs. © 2020 IEEE.

This paper presents an experimental demonstration of analog radio-over-fiber (ARoF) fronthaul for high-bandwidth, high-capacity millimeter wave (mm-wave) extended fifth generation mobile network (5G) new radio (NR) signals over an optical distribution network with optical space division multiplexing (SDM). ARoF is shown to alleviate fronthaul capacity bottlenecks, transporting an 800 MHz wide extended 5G NR signal and allowing to maintain full centralization in a centralized radio access network (C-RAN). The proposed ARoF fronthaul architecture features a transmitter that generates the ARoF signal and an optical signal carrying a reference local oscillator (LO) employed for downconversion at the remote unit (RU) from a single radio frequency (RF) reference at the central office (CO). An SDM based RAN with 7-core multi-core fiber (MCF) allows parallel transport of the uplink ARoF signal and reference LO at the same wavelength over separate cores. Transmission of an 800 MHz wide extended 5G NR fronthaul signal over 7-core MCF is shown with full real-time processing, achieving 1.4 Gbit/s with BER

Fifth-generation (5G) mobile networks consist of a range of novel technologies to fulfill different and exigent requirements and serve a wide range of services. To reach this, analog radio over fiber (ARoF) fronthaul with millimeter-wave (mm-wave) cells is a firm candidate to be part of the 5G architecture. Nonetheless, combined mm-wave and ARoF systems present new challenges such as high free-space path loss (FSPL), phase noise, chromatic dispersion, and other impairments. Therefore, the selection of the modulation format is crucial to reduce these effects and their impact. This work compares and analyzes different modulation formats in this type of system in order to choose the best waveform candidate for mm-wave 5G and beyond with ARoF fronthaul. An experimental comparison of OFDM, SC-FDM, UFMC, GFDM, and multi-CAP, shows that the standard OFDM may not be the best choice for mm-wave 5G.

© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works In this paper, a combined non-orthogonal multiple access (NOMA) and multiband carrierless amplitude phase modulation (multiCAP) scheme is proposed for capacity enhancement of and flexible resource provisioning in 5G mobile networks. The proposed scheme is experimentally evaluated over a W-band millimeter wave radio-over fiber system. The evaluated NOMACAP system consists of six 1.25GHz multiCAP bands and two NOMA levels with quadrature phase shift keying and can provide an aggregated transmission rate of 30 Gbit/s. The proposed system can dynamically adapt to different user densities and data rate requirements. Bit error rate performance is evaluated in two scenarios: a low user density scenario where the system capacity is evenly split between two users and a high user density scenario where NOMA and multiCAP are combined to serve up to twelve users with an assigned data rate of 2.5 Gbit/s each. The proposed system demonstrates how NOMA-CAP allows flexible resource provisioning and can adapt data rates depending on user density and requirements.

The introduction of millimeter wave (mm-wave) frequency bands for cellular communications with significantly larger bandwidths compared to their sub-6 GHz counterparts, the resulting densification of network deployments and the introduction of antenna arrays with beamforming result in major increases in fronthaul capacity required for 5G networks. As a result, a radical re-design of the radio access network is required since traditional fronthaul technologies are not scaleable. In this article the use of analog radio-over-fiber (ARoF) is proposed and demonstrated as a viable alternative which, combined with space division multiplexing in the optical distribution network as well as photonic integration of the required transceivers, shows a path to a scaleable fronthaul solution for 5G. The trade-off between digitized and analog fronthaul is discussed and the ARoF architecture proposed by blueSPACE is introduced. Two options for the generation of ARoF two-tone signals for mm-wave generation via optical heterodyning are discussed in detail, including designs for the implementation in photonic integrated circuits as well as measurements of their phase noise performance. The proposed photonic integrated circuit designs include the use of both InP and SiN platforms for ARoF signal generation and optical beamforming respectively, proposing a joint design that allows for true multi-beam transmission from a single antenna array. Phase noise measurements based on laboratory implementations of ARoF generation based on a Mach–Zehnder modulator with suppressed carrier and with an optical phase-locked loop are presented and the suitability of these transmitters is evaluated though phase noise simulations. Finally, the viability of the proposed ARoF fronthaul architecture for the transport of high-bandwidth mm-wave 5G signals is proven with the successful implementation of a real-time transmission link based on an ARoF baseband unit with full real-time processing of extended 5G new radio signals with 800 MHz bandwidth, achieving transmission over 10 km of 7-core single-mode multi-core fiber and 9 m mm-wave wireless at 25.5 GHz with bit error rates below the limit for a 7% overhead hard decision forward error correction.

The increasing demands for high capacity and ultra-low latency services require to introduce a 5G mobile communications infrastructure based on a centralized radio access network with space division multiplexed optical fronthaul using radio-over-fiber. The transmission of carrier aggregated 5G OFDM signals over an analog radio-over-fiber fronthaul link is experimentally demonstrated. Multi-Gbit/s data rates are achieved in limited bandwidth, with BER below the 25 % overhead FEC limit after millimeter-wave wireless transmission over 2.2 m.

The most radical evolution in recent mobile communication technology is imminent in the coming years. The fronthaul network architecture is part of this evolution and is expected to support dense deployment of infrastructure to provide increased bandwidth and ultra-low latency for 5th generation (5G) networks in a cost-effective manner. The new fronthaul architecture called cloud radio access network (C-RAN) has been introduced over the last years to increase scalability, manageability, and flexibility of mobile systems. In this context, this paper addresses the principal technology enablers of the C-RAN 5G fronthaul architecture, namely radio-over-fiber, ribbon optical fibers, wavelength-division multiplexing, and millimeter wave (mmWave) frequencies. The convergence of optical fiber networks and mmWave radio pave the way towards a truly efficient fronthaul infrastructure for 5G mobile communications with seamless connectivity for millions of devices and quality-of-service guarantees in terms of latency for the first time ever. We perceive a network scenario with seamless starting and ending interfaces by exploiting space diversity in both radio frequency and optical domains with efficient integrated photonics technology. Furthermore, we introduce the ongoing developments of the Eindhoven-based 5G Brainport testbed towards an open environment for validation and test of end-to-end emerging applications benefitting from the 5G key-performance indicators.

The fifth generation (5G) mobile systems can be considered the way to ubiquitous Internet, pervasive computing paradigm, and a revolution in industries like automotive, media and entertainment, and eHealth. New 5G fronthaul systems based on centralized radio access networks will eventually use technology enablers such as reconfigurable optical add-drop multiplexers, space-division multiplexing, ribbon fibers, software-defined networking, multiple-input multiple-output signaling, analog radio-over-fiber signals, and beamforming. In this context, this paper addresses the principal technology enablers of the 5G PPP phase 2 projects blueSPACE and 5G-PHOS and their potential interoperability. The convergence of 5G key-performance indicators (KPIs) along with methodologies and usage scenarios is also addressed. Furthermore, the 2020 European championship is perceived here as a unique opportunity to leverage a 5G pan-European trial platform. The technologies developed in both projects are seen as potential candidates for next generation mobile networks, where ultra-low latency, energy efficiency, and millions of connected devices are major network KPIs requirements.

5G mm-wave communications requires a highly densified network of radio access stations to ensure sufficient coverage. Low-complexity nodes based on C-RAN and ARoF fronthaul combined with advanced antenna concepts offer a suitable and potentially low cost technology for single and multi-beam 5G applications.

This paper presents the novel SDN/NFV 5G fronthaul network scenarios deployed in the blueSPACE project. blueSPACE envisions the upgrade of the fronthaul network to include optical SDM transmission for further increasing the network capacity. One of the novelties is the introduction of ARoF transceivers to reduce the 5G fronthaul bandwidth requirements, in addition to the DRoF solutions that are used for the 4G fronthaul interface and the 3GPP's NGFI. Moreover, ARoF transceivers enable to develop optical beamforming technologies for beam steering and multi-beam transmission. Finally, power of fiber solutions to remotely feed small cells are also considered.

The key-performance indicators (KPIs) that will be delivered by 5G networks such as extremely low-latency, high capacity, robustness and highly flexible network are key enablers for applications such as autonomous driving, cooperative robotics, transport and processing of large volumes of video and images, to name but a few. This paper presents the ongoing build up and deployment of the Eindhoven based 5G-Brainport testbed towards an open environment for validation and test of end-to-end applications benefitting from the 5G KPIs.

This paper regards photonically enabled millimeter wave links for use in 5G. Following a short review of the tradeoff between link directivity, achievable capacity and coverage area, it discusses the use of optical space division multiplexing as suggested in the 2nd phase 5G-PPP project blueSPACE. Finally it relates the latter to the potential use of millimeter waves for broad- and multicast within the framework of 5G.

Analog radio-over-fiber transmission and millimeter-wave and terahertz signal generation through photonic heterodyning are a valuable and versatile solution for many applications. This talk will discuss recent advances, focusing 5G networks, wireless communications and sensing applications.

This manuscript introduces a 5G radio access network architecture concept based on ultra-dense wavelength division multiplexing (UDWDM) and incorporating an optical fronthaul network that uses a novel wireless antenna system for radio frequency transmission and reception. A ring topology is proposed where optical signals travel within the 5G UDWDM passive optical networks and millimeter waves are generated in the optical line terminals by optical heterodyning. The wireless transmission of the millimeter waves is conducted by an innovative phased array fed reflector antenna approach for mobile communications that grants high antenna gain due to highly focused radiation characteristics, as well as multiplexing gain by multiple beam generation. Furthermore, beam steering is provided by a radio frequency analog beamformer network. Finally, implementation options synthesizing the total system are discussed.

In this paper a new type of radio access unit is proposed and demonstrated. This unit is composed only of the reduced amount of components (compared to conventional unit designs) to optically generate wireless signals on the W-band (75-110GHz) in combination with a switching system. The proposed system not only achieves BER values below the FEC limit, but gives an extra level of flexibility to the network by easing the redirection of the signal to different antennas.

In this paper, an experimental analysis of the phase noise in an OFDM ARoF setup at 25 GHz for beyond 5G is presented. The configuration of the setup allows to gradually scale the final phase noise level of the system. Moreover, an OFDM phase noise mitigation method with low complexity and delay is proposed and explained. The proposed method is an advanced version of the LI-CPE algorithm. The advanced LI-CPE version avoids the one OFDM symbol delay of its antecedent. In addition, the yields of using both methods are shown under different phase noise levels and with different subcarrier spacings. Finally, it is experimentally proven that the proposed method performs better than its previous version.

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 5th 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.

Emerging 5G wireless systems require technologies for increased capacity, guarantee robustness, low latency and flexibility. We review a number of approaches to provide the above based on microwave photonics and hybrid optical fiber-wireless communication techniques.

The fifth-generation (5G) of mobile communications is expected to enable emerging use cases like autonomous driving vehicles, cooperative robotics, and innovative healthcare systems. These applications primarily will be available in ultra-dense urban areas, where optical fiber infrastructure is already deployed and will become part of the 5G ecosystem. The further integration of fiber and mobile along with optical wireless technology like visible light communications (VLC) can both enable never thought before use cases and satisfy challenging key performance indicators such as increased number of connected devices, lower energy consumption, and reduced latency. In this context, we introduce the integration of 5G, optical fiber network, and VLC technologies for creating end-to-end connectivity solutions and supporting new use cases in dense urban areas. We describe the network architecture and its functionalities upon the integrated technologies. We also describe and exploit several use cases for highly-dynamic and-densely populated urban areas that can be for the first time simplified by using the proposed integrated solution. The integration of different technologies is perceived here as a unique prospective communication platform towards ubiquitous communication with anywhere, anytime, anyhow connectivity for any use case or business case that can arise in the future.

This work introduces a subsystem level cosimulation for generation, boosting and transmission of millimeter wave signals for 5G applications. The simulation processes to model the full equivalent circuit of uni-Traveling carrier photodiodes based on reflection coefficient measurements are analyzed. The optoelectronic lumped equivalent is co-integrated with a transimpedance amplifier design synthesized by high speed transistors. The proposed broadband component achieves competitive performance characteristics exhibiting high gain.

We experimentally analyze the ARoF based on OPLL mm-Wave generation performance for 5G fronthaul. Remarkable performance improvements are achieved for all 5G NR numerologies and different OPLL configurations despite their inherently high phase noise level.

A reconfigurable radio access unit able to switch wavelength, RF carrier frequency and optical path is experimentally demonstrated. The system is able to do the switching processes correctly, while achieving BER values below FEC limit.

The blueSPACE project focuses on the study of innovative technologies to overcome the limitations of current fronthaul networks. The key technology proposed is space-division multiplexing, which makes it possible to increase the capacity available in conventional single-mode fibers, effectively encompassing this capacity to the forecasted bandwidth demands imposed by 5G mobile communications. In this paper, we present the innovative optical fronthaul infrastructure proposed in the project and the tailored extensions to the European Telecommunications Standards Institute network function virtualization management and orchestration architecture for this enhanced infrastructure together with practical implementation considerations. (C) 2020 Optical Society of America.

5G mobile networks aim to support a large variety of services with different and demanding requirements. To achieve this, analog radio over fiber (ARoF) fronthaul along with millimeter-wave (mmWave) cells is a strong candidate to be part of the 5G architecture. Very high throughput can be achieved by using mmWave signals due to the large available bandwidths, which combines well with the advantages of employing ARoF technology. Nevertheless, combined mmWave and ARoF systems face a particular challenge as the impacts of both channels—such as high free-space path loss, phase noise, chromatic dispersion, and other degrading effects—affect the signal without the possibility for intermediate restoration. The selection of the signal waveforms plays an important role in reducing these defects. In addition, waveforms are one of the keys in the physical layer available towards satisfying the requirements for 5G and beyond. In this manuscript, several key requirements are presented to determine the merit of candidate waveform formats to fulfill the 5G requirements in the mmWave ARoF architecture. An overview of the different suitable waveforms for this architecture is provided, discussing their advantages and disadvantages. Moreover, a comprehensive comparison in terms of different requirements is also presented in this paper.