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The article analyzes the total cost of ownership (TCO) of 5G fronthauling solutions based on analog and digital radio-over-fiber (RoF) architectures in cloud radio access networks (C-RANs). The capital and operational expenditures (CAPEX, OPEX) are assessed, for a 10-year period, considering three different RoF techniques: intermediate frequency analog RoF (IF-A-RoF), digital signal processing (DSP) assisted analog RoF (DSP-A-RoF), and digital RoF (D-RoF) based on the common public radio interface (CPRI) specifications. The greenfield deployment scenario under exam includes both fiber trenching (FT) and fiber leasing (FL) options. The TCO is assessed while varying (i) the number of aggregated subcarriers, (ii) the number of three-sector antennas located at the base station, and (iii) the mean fiber-hop length. The comparison highlights the significance that subcarrier aggregation has on the cost efficiency of the analog RoF solutions. In addition, the analysis details the contribution of each cost category to the overall CAPEX and OPEX values. The obtained results indicate that subcarrier aggregation via DSP results in high cost efficiency for a mobile fronthaul network, while a CPRI-based architecture together with FL brings the highest OPEX value.

With the introduction of the next generation 5G systems, an unprecedented bit rate demand for optical transport infrastructure is expected, in addition to the need to ensure low costs, low power consumption, and low latency. With the current analog radio over fiber approach, high spectral efficiency is achieved, therefore, this is a fundamental technology for the next generation fronthaul system. This thesis addresses the possibility of using an analog radio-over-fiber system in a fronthaul of a Cloud Radio Access Network, avoiding the well-known bandwidth multiplication issue associated with the digitization of radio signals. Using a low-cost directly modulated laser and a standard PIN, we have experimentally demonstrated how to obtain a 5G-compliant EVM on all component carriers by optimizing power and bit loading between component carriers. Com a introdução dos sistemas 5G de próxima geração, é esperado uma demanda por taxa de bits sem precedentes para infraestrutura de transporte óptico, para além da necessidade de garantir baixos custos, baixo consumo de energia e baixa latência. Com a abordagem atual de rádio sobre fibra analógico, consegue-se alcançar uma alta eficiência espectral, portanto, esta é uma tecnologia fundamental para o sistema fronthaul de próxima geração. Esta dissertação aborda a possibilidade de usar um sistema analógico de rádio sobre fibra num fronthaul de uma Cloud Radio Access Network, evitando o conhecido problema de multiplicação de largura de banda associado à digitalização de sinais de rádio. Usando um laser diretamente modulado de baixo custo e um PIN padrão, demonstrámos experimentalmente como obter um EVM compatível com 5G em todas as portadoras, otimizando o power e bit loading entre as portadoras. Mestrado em Engenharia Eletrónica e Telecomunicações

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We demonstrate two advanced services deployed in a novel SDN/NFV optical fronthaul network combining analog radio over fiber (ARoF) and power over fiber (PoF); vertical service management for virtual content delivery networks (vCDNs), and user mobility and remote optical power management for femto cells., Grant numbers : AURORAS - Autonomic and disaggregated optical networks leveraging edge computing and photonic technologies (RTI2018-099178-B-I00).

In this paper we analyze the perspective of digitized radio over fiber (DRoF) fronthaul, showing how to meet the requirements to cope with the future radio access networks (RANs). This entails the introduction of space division multiplexing (SDM) while increasing the flexibility and capacity of the DRoF transceivers.Since the evolution of the DRoF fronthaul is being revised and re-defined, in the blueSPACE project we propose two different DRoF transceiver options. The first option consists on simple transceiver, based on the recent standard specifications and, therefore, expected to be deployed in the short-term. The second options is a more advanced transceiver that features high flexibility, relying on a strong DSP and targeting a long-term deployment. Besides a basic characterization of both solutions, we also analyze additional aspects related to the design and implementation of these two DRoF solutions and their integration into an SDM based RAN. This includes the programmability and interaction with the control plane.

In this paper we propose a passive optical network based on hybrid wavelength/space division multiplexing for digitized fronthaul delivery, capable to meet the requirements of the future radio access networks. Besides explaining this specific network architecture, we also discuss the different programmable data plane elements. Additionally, we evaluate and demonstrate the support of an extended version of 5G-NR radio signals.

In this paper we analyze the perspective of digitized radio over fiber (DRoF) fronthaul, showing how to meet the requirements to cope with the future radio access networks (RANs). This entails the introduction of space division multiplexing (SDM) while increasing the flexibility and capacity of the DRoF transceivers.Since the evolution of the DRoF fronthaul is being revised and re-defined, in the blueSPACE project we propose two different DRoF transceiver options. The first option consists on simple transceiver, based on the recent standard specifications and, therefore, expected to be deployed in the short-term. The second options is a more advanced transceiver that features high flexibility, relying on a strong DSP and targeting a long-term deployment. Besides a basic characterization of both solutions, we also analyze additional aspects related to the design and implementation of these two DRoF solutions and their integration into an SDM based RAN. This includes the programmability and interaction with the control plane.

[EN] In this work we report a comprehensive experimental study targeting the dimensioning of the next-generation multicore-fibre (MCF) optical fronthaul employing space-division multiplexing (SDM). This fronthaul is capable of simultaneous provision of multiple radio-access technologies (multi-RATs) with advanced multi-antenna MIMO capabilities per RAT. The different parameters required for fronthaul dimensioning are evaluated considering state-of-the-art 4G LTE-Advanced altogether other legacy wireless standards in operation nowadays. In particular, the modulation characteristics, the antenna quality requirements (in terms of EVM, phase error or rho) and the signal-to-noise ratio (SNR) thresholds are evaluated employing fully-standard cellular signals transmitted on a multicore fibre (MCF) fronthaul. The study includes bi-directional signal transmission and multi-antenna MIMO multiplexing. The MCF optical fronthaul is evaluated with a multiplexed transmission of 2G, 3G, 3.9G and 4G MIMO signals in radio-over-multicore-fibre (RoMCF) employing a commercially available four-core MCF. The SNR requirements at the transmitter antenna are obtained for each cellular signal considering GSM, EDGE, EGPRS2-A, cdma2000 1xEV-DO, UMTS HSPA+ and LTE-Advanced standards. LTE-Advanced singleantenna and two-antenna systems implementing 2 x 2 MIMO transmission can be accomplished with SNR levels over 25 dB. In the case of LTE-Advanced 4 x 4 MIMO multiplexing over four cores of MCF media, 32 dB SNR is needed to achieve almost four times provided bitrate per user., This research was supported in part by Spain National Plan MINECO/FEDER UE TEC2015-70858-C2-1-R XCORE and GVA AICO/2018/324 NXTIC projects. The work of M. Morant is supported by Spain Juan de la Cierva, Spain IJCI-2016-27578 grant and Fundacion BBVA Leonardo 2018 HYPERCONN project.

We demonstrate combined WDM/SDM delivery of mobile fronthaul in PONs, employing SDN-enabled S-BVTs based on adaptive multicarrier modulation. Experiments show successful BBU-RRU connectivity on several deploying strategies while coping with capacities beyond 50Gb/s per flow.

This paper provides an assessment of the total cost of ownership (TCO) of a number of 5G fronthauling solutions based on digital and analog radio-over-fiber (RoF) architectures in cloud radio access network (C-RAN). We computed the capital and operational expenditures (CAPEX, OPEX) in the case of an optical fiber aggregation network based on a ring topology. Three different RoF architectures were considered: intermediate frequency analog RoF (IF-A-RoF), digital signal processing assisted analog RoF (DSP-A-RoF), and digital RoF (D-RoF) based on the common public radio interface (CPRI). A greenfield scenario considering both fiber deployment and fiber leasing was analyzed. The results presented in the paper show how the TCO changes with the number of aggregated carriers for the considered RoF architectures and fiber deployment strategy. They also reveal the impact that each cost category has on the overall CAPEX and OPEX value.

Nowadays, the architecture of the mobile network is in full evolution to ensure the increase in terms of bit rate between the Central (CO) (core networks) and various terminals such as mobiles, computers, tablets in order to satisfy the users. To address these challenges of the future, the C-RAN (Cloud or Centralized-RAN) network is known as a 5G solution. In the C-RAN context, all BBUs (Base Band Units) are centralized in the CO, only the RRH (Remote Radio Head) remain at the head of the base station (BS). A new segment between BBUs and RRHs appears called "fronthaul". It is based on D-ROF (digital radio-overfiber) transmissions and carries the digital radio signal at a high bit rate using the Common Public Radio Interface (CPRI) protocol. Taking into account CAPEX and OPEX, the ANR LAMPION project has proposed the Self-seeded Reflective Semiconductor Optical Amplifier (RSOA) technology in order to make the solution more flexible and overcome the need for colored transmitters / receivers in the context of PON-WDM (Wavelength Division Multiplexing Passive Optical Network). Nevertheless, it is necessary to add a FEC (forward error corrector) in the transmission to ensure the quality of service. So the objective of this thesis is to find the most suitable FEC to apply in the C-RAN context. Our work has focused on the use of LDPC codes, chosen after performance comparisons with other types of codes. We have specified the parameters (code performance, matrix size, cycle, etc.) required for LDPC codes to obtain the best performance. Hard-decision LDPC algorithms were chosen after considering the tradeoff between circuit complexities and performance. Among these hard-decision algorithms, the GDBF (gradient descent bit-flipping) was the best solution. Taking into account a CAN 2-Bit in the channel led us to propose a variant: the BWGDBF (Balanced weighted GDBF). Optimizations have also been made with respect to the convergence of the algorithm and latency. Finally, we managed to implement our own algorithm on the Spartan FPGA 6 xc6slx16. Several methods have been proposed to achieve a latency of 5 μs desired in the C-RAN context. This thesis was supported by the project ANR LAMPION (Lambada-based Access and Metropolitan Passive Optical Networks).; De nos jours, l’architecture du réseau mobile est en pleine évolution pour assurer la montée en débit entre les Centraux (CO) (réseaux coeurs) et différents terminaux comme les mobiles, ordinateurs, tablettes afin de satisfaire les utilisateurs. Pour faire face à ces défis du futur, le réseau C-RAN (Cloud ou Centralized-RAN) est connu comme une solution de la 5G. Dans le contexte C-RAN, toutes les BBUs (Base Band Units) sont centralisées dans le CO, seules les RRH (Remote Radio Head) restent situées à la tête de la station de base (BS). Un nouveau segment entre les BBUs et RRHs apparait nommé « fronthaul ». Il est basé sur des transmissions D-ROF (digital radio-overfiber) et transporte le signal radio numérique à un débit binaire élevé en utilisant le protocole CPRI (Common Public Radio Interface). En prenant en compte le CAPEX et l’OPEX, le projet ANR LAMPION a proposé la technologie RSOA (Reflective Semiconductor Optical Amplifier) auto alimenté afin de rendre la solution plus flexible et s’affranchir d’émetteurs/récepteurs colorés dans le cadre de transmission WDM-PON (Wavelength Division Multiplexing Passive Optical Network). Néanmoins, il est nécessaire d’ajouter un FEC (forward error corrector) dans la transmission pour assurer la qualité de service. Donc l’objectif de cette thèse est de trouver le FEC le plus adéquat à appliquer dans le contexte C-RAN. Nos travaux se sont focalisés sur l’utilisation de codes LDPC, choisis après comparaisons des performances avec les autres types de codes. Nous avons précisé les paramètres (rendement du code, taille de la matrice, cycle, etc.) nécessaires pour les codes LDPC afin d'obtenir les meilleures performances. Les algorithmes LDPC à décisions dures ont été choisis après considération du compromis entre complexités de circuit et performance. Parmi ces algorithmes à décision dures, le GDBF (gradient descent bit-flipping) était la meilleure solution. La prise en compte d’un CAN 2-Bit dans le canal nous a amené à proposer une variante : le BWGDBF (Balanced weighted GDBF). Des optimisations ont également été faites en regard de la convergence de l'algorithme et de la latence. Enfin, nous avons réussi à implémenter notre propre algorithme sur le FPGA Spartan 6 xc6slx16. Plusieurs méthodes ont été proposées pour atteindre une latence de 5 μs souhaitée dans le contexte C-RAN. Cette thèse a été soutenue par le projet ANR LAMPION (Lambada-based Access and Metropolitan Passive Optical networks).

To meet challenging 5G capacity requirements, operators are densifying their cellular networks by deploying additional small cells to cover hot spots, and such an increase in the number and density of cells may result in excessive numbers of handovers. In this study, we propose a handover reduction mechanism implemented in a cloud radio access network (CRAN) by exploiting the high capacity of an optical access network serving as a “fronthaul.” CRAN has been proposed as a 5G radio access network architecture, where the digital unit (DU) of a conventional base station (BS) is separated from the radio unit (RU) and moved to the “cloud” (DU-cloud) for better mobility management and cost saving. Separating RUs and DUs requires a low-latency and high-bandwidth 5G transport network to handle “fronthaul” traffic, for which optical access is an excellent choice. Here, we present a new 5G architecture, called virtualized-CRAN (V-CRAN), moving toward a cell-less 5G mobile network architecture. We leverage the concept of a “virtualized-BS” (V-BS) that can be formed by exploiting several enabling technologies such as software-defined radio and coordinated multi-point transmission/reception. A V-BS can be formed on a per-user basis by allocating virtualized resources on demand so that common signals can be jointly transmitted from multiple RUs to the user without triggering handover. We first model the handover reduction optimization problem for a scenario where future mobility information is known, and then propose a suite of algorithms for a scenario where future information is unknown. Simulation results show that V-CRAN can enhance the throughput of users at the cell-edge, as well as significantly reduce the number of handovers, handover delay, and failure rate.

To make the most of spatial efficiency, we design 64-core trench-assisted multi-core fiber with the maximum crosstalk less than -14dB/20km, which is appropriate for the optical wireless fronthaul systems with inherent MIMO function. Published version

In this paper we propose a passive optical network based on hybrid wavelength/space division multiplexing for digitized fronthaul delivery, capable to meet the requirements of the future radio access networks. Besides explaining this specific network architecture, we also discuss the different programmable data plane elements. Additionally, we evaluate and demonstrate the support of an extended version of 5G-NR radio signals.

In this paper we propose a passive optical network based on hybrid wavelength/space division multiplexing for digitized fronthaul delivery, capable to meet the requirements of the future radio access networks. Besides explaining this specific network architecture, we also discuss the different programmable data plane elements. Additionally, we evaluate and demonstrate the support of an extended version of 5G-NR radio signals., Grant numbers : AURORAS - Autonomic and disaggregated optical networks leveraging edge computing and photonic technologies (RTI2018-099178-B-I00).