Showing papers presented at "International Conference on Transparent Optical Networks in 2018"

Fast, Noise-Free Memory for Photon Synchronization at Room Temperature

Abstract: Future quantum photonic networks require coherent optical memories for synchronizing quantum sources and gates of probabilistic nature. Room temperature operation is also desirable for ease of scaling up. Until now, however, room-temperature atomic memories have suffered from an intrinsic read-out noise due to spontaneous four-wave-mixing. Here we demonstrate a new scheme for storing photons at room temperature, the fast ladder memory (FLAME). In this scheme, stimulated two-photon absorption is used instead of the previously used stimulated Raman scattering. As here the competing spontaneous processes would require spontaneous absorption of an optical photon, rather than emission, the noise is greatly suppressed. Furthermore, high external efficiency can be achieved as the control is well separated in frequency from the signal, and could be filtered out using highly efficient interference filters. We run the protocol in rubidium vapour, both on and off single-photon resonance, demonstrating a ratio of 50 between storage time and signal pulse width, an external total efficiency of over 25%, and only 2.3 × 10−4 noise photons per extracted signal photon. This paves the way towards the efficient synchronization of probabilistic gates and sources at room temperature, and the controlled production of large quantum states of light.

Deep Learning-Based Traffic Prediction for Network Optimization

Abstract: In recent years, researchers realized that the analysis of traffic datasets can reveal valuable information for the management of mobile and metro-core networks. That is getting more and more true with the increase in the use of social media and Internet applications on mobile devices. In this work, we focus on deep learning methods to make prediction of traffic matrices that allow us to proactively optimize the resource allocations of optical backbone networks. Recurrent Neural Networks (RNNs) are designed for sequence prediction problems and they achieved great results in the past years in tasks like speech recognition, handwriting recognition and prediction of time series data. We investigated a particular type of RNN, the Gated Recurrent Units (GRU), able to achieve great accuracy (< 7.4 of mean absolute error). Then, we used the predictions to dynamically and proactively allocate the resources of an optical network. Comparing numerical results of static vs. dynamic allocation based on predictions, we can estimate a saving of 66.3% of the available capacity in the network, managing unexpected traffic peaks.

Maximizing the Capacity of Installed Optical Fiber Infrastructure Via Wideband Transmission

Abstract: Optical wideband communication systems aim at transmitting over several, if not all, of the low-loss windows of single-mode fibre, i.e. the O-, E-, S-, C-, and L-band. Recently, there has been a clear trend in the industry to support additional bands beyond C-band. While C+L-band solutions are close to commercialization and first products are emerging, the research focus is shifting to supporting also the S-band and, finally, the whole O- to L-band (resulting in a total transmission bandwidth of 365 nm). This contribution highlights the perspectives of wideband communication systems for optical networks, providing a realistic roadmap for their deployment. Particular emphasis is paid on a first analysis to estimate the maximum transmittable capacity over these systems.

Energy Efficiency of Server-Centric PON Data Center Architecture for Fog Computing

Abstract: In this paper, we utilize Mixed Integer Linear Programming (MILP) models to compare the energy efficiency and performance of a server-centric Passive Optical Networks (PON)-based data centers design with different data centers networking topologies for the use in fog computing. For representative MapReduce workloads, completion time results indicate that the server-centric PON-based design achieves 67% reduction in the energy consumption compared to DCell with equivalent performance.

Impact of Crosstalk Estimation Methods on the Performance of Spectrally and Spatially Flexible Optical Networks

Abstract: We focus on a crosstalk-aware lightpath planning problem in a spectrally and spatially flexible optical network (SS-FON) in which spectral super-channels (SChs) are carried over multi-core fibers (MCFs) and distance-adaptive transmission is considered. The problem concerns establishing lightpath connections for a set of traffic demands in such a way that the inter-core crosstalk (XT) impairment affecting the quality of transmitted signals does not exceed allowable threshold levels. The aim of this work is to compare the methods ensuring required XT levels. In particular, we analyze two basic methods: a) based on worst-case XT and b) using precise XT estimation. Both methods are implemented in a XT-aware routing, spatial mode, and spectrum allocation (RSSA) algorithm, which is applied to solve the planning problem. The obtained numerical results show the impact of considered XT estimation methods on network performance.

A Simple User Grouping and Pairing Scheme for Non-Orthogonal Multiple Access in VLC System

Abstract: In this paper, a simple user grouping and pairing scheme is proposed for non-orthogonal multiple access (NOMA) and is applied for the downlink visible light communication (VLC) system. The proposed scheme is a mix of both NOMA and the conventional orthogonal multiple access (OMA) schemes. In the proposed scheme, every two users are paired using NOMA and all pairs are allocated with conventional OMA. The performance of the proposed scheme is compared to the performance of the conventional OMA in terms of the maximum sum rate. Simulation results show that the proposed scheme provides higher sum rate compared with the OMA scheme.

Analog Radio-over-Fiber Solutions for 5G Communications in the Beyond-CPRI Era

Abstract: Current research efforts on 5G RAN strongly focus on pico-cells deployment based on mmWave radio, optical/wireless convergence to support massive-MIMO and a cloud-centric operation of BBUs. Industrial and academic institutions concur that it is of great importance to develop evolutional paradigms that ensure the functional combination of the above technologies into a 5G cellular architecture and its associated ecosystems providing new vertical services. This paper aims to explore the role of Analog RoF solutions moving beyond CPRI implementations for future 5G architectures, highlighting the impact of digital-signal-processing to proposed network implementations. A DSP-assisted IFoF concept to support 60-GHz multi-band wireless connectivity is successfully demonstrated through preliminary experiments showing 12 Gb/s downlink connectivity with centralized processing at BBU side.

Geometrically-shaped 64-point Constellations via Achievable Information Rates

Abstract: Achievable information rates (AIRs) are discussed as a performance metric to design optimized geometrically-shaped constellations. Mutual information and generalized mutual information are used to maximize the AIRs of 64-point constellations.

Jamming Attack Detection in Optical UAV Networks

Abstract: Unmanned Aerial Vehicles (UAVs) have several applications in civil and military domains. The high data rate connectivity required by UAVs makes the use of Free Space Optical (FSO) communications very suitable. In this paper, we consider a three-layer optical UAV network architecture allowing the real-time delivery of collected data. The UAV network is exposed to several types of attacks such as replay attacks, black hole attacks, jamming attacks, etc. In this work, we are interested to a specific class of attacks which vises to perform an intentional interference with signals transmitted between two UAVs on an FSO link, which is the jamming attack. This attack can be seen as a form of denial of service attacks since it prevents the transmitter and the receiver to properly communicate through the FSO link and to use the network resources. In this paper, we present some jamming attack scenarios that can occur in an optical UAV network, then we present a countermeasure approach allowing to recover the transmitted signals in the presence of a jamming attack.

A C-RAN Based 5G Platform with a Fully Virtualized, SDN Controlled Optical/Wireless Fronthaul

Abstract: This paper describes in detail the design of a 5G platform based on the C-RAN architecture, with a fully virtualized Radio Access Network (RAN) and an optical/wireless Fronthaul. The wireless and optical domains are controlled by a hierarchy of Software Defined Networking (SDN) controllers, which are responsible for end-to-end optimization of the platform, including the Fronthaul and 5G air interfaces. The proposed architecture adopts a modular eNodeB (eNB) design, where virtualized BBU and RRH entities are implemented with Commercial Off-Τhe-Shelf (COTS) components. Moreover, a mmWave RAU is connected to the BBU via a feeder optical fiber, interconnecting one or more RRH units with the BBU over mmWave interfaces. COTS components and Ethernet interfaces are employed for C-RAN prototyping of our platform, facilitating flexibility, cost reduction and increased scalability.

Optimal Design of 5G Networks in Rural Zones with UAVs, Optical Rings, Solar Panels and Batteries

Abstract: We focus on the problem of designing a 5G network architecture to provide coverage in rural areas. The proposed architecture is composed of 5G Base Stations carried by Unmanned Aerial Vehicles (UAVs), and supported by ground sites interconnected through optical fiber links. We also consider the dimensioning of each site in terms of the number of Solar Panels (SPs) and batteries. We then formulate the problem of cost minimization of the aforementioned architecture, by considering: i) the cost for installing the sites, ii) the costs for installing the SPs and the batteries in each site, iii) the costs for installing the optical fiber links between the installed sites, and iv) the scheduling of the UAVs to serve the rural areas. Our results, obtained over a representative scenario, reveal that the proposed solution is effective in limiting the total costs, while being able to ensure the coverage over the rural areas.

An Insight into the Total Cost of Ownership of 5G Fronthauling

Abstract: 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.

Filterless and Semi-Filterless Solutions in a Metro-HAUL Network Architecture

Abstract: Filterless optical networks based on broadcast-and-select nodes have been proven to be a cost-effective alternative to active photonic network solutions in core networks. However, due to the emergence of novel metro-based high-bandwidth cloud-based services (e.g., Virtual Reality, 4K Video-on-Demand, etc.), filterless solutions have started to attract research attention also in the metro area. In this paper, we evaluate the performance of fully-filterless and semi-filterless (i.e., hybrid solutions between fully-filterless and active photonic architectures) optical-network architectures in terms of cost of network elements and spectrum utilization, in a metro-network scenario. Our evaluations show that, due to the ring-based hierarchical nature of metro networks, fully-filterless architectures tend to require excessive spectrum utilization as the broadcast effect spreads among all hierarchical rings. On the contrary, semi-filterless network architectures seem more promising due to the presence of filters that fend off the propagation of unfiltered channels. The results also show that it is more advantageous to deploy filters at nodes of the lower network levels than at nodes of higher network levels.

Capacity Increase and Hardware Savings in DWDM Networks Exploiting Next-Generation Optical Line Interfaces

Abstract: In transport networks, each generation of optical line interfaces brings the prospect of even higher capacity and further reductions in the cost per bit transported. Currently deployed line interface technology already exploits coherent detection and advanced modulation formats to attain high spectral efficiency as well as to flexibly adapt the modulation format to the path characteristics, effectively trading-off capacity for reach. The upcoming generation of optical line interfaces will take these capabilities one step further by enriching the set of modulation formats supported and by doubling the maximum symbol rate at which each line interface can operate. This work presents a preliminary assessment of the network-wide benefits of deploying next-generation line interfaces. Considering two reference transport networks and modelling three different sets of channel formats, which approximately match three consecutive generations of line interface technology, a full design of the network is reported. The network simulation results highlight the capacity increase and the line interface and tributary card savings enabled by the upcoming generation of line interfaces.

Optimal Design of Filterless Optical Networks

Abstract: We study the design of filterless optical networks in order that the maximum link network capacity is minimized. We propose a one step model to simultaneously generate and provision filterless sub-networks, together with a solution process that allows its exact solution. Numerical experiments illustrate the performance of the proposed optimization model and algorithm.

Energy Efficiency of Fog Computing Health Monitoring Applications

Abstract: Fog computing offers a scalable and effective solution to overcome the increasing processing and networking demands of Internet of Thing (IoT) devices. In this paper, we investigate the use of fog computing for health monitoring applications. We consider a heart monitoring application where patients send their 30 minute recording of Electrocardiogram (ECG) signal for processing, analysis, and decision making at fog processing units within the time constraint recommended by the American Heart Association (AHA) to save heart patients when an abnormality in the ECG signal is detected. The locations of the processing servers are optimized so that the energy consumption of both the processing and networking equipment are minimised. The results show that processing the ECG signal at fog processing units yields a total energy consumption saving of up to 68% compared to processing the at the central cloud.

Testing Facilities for End-to-End Test of Vertical Applications Enabled by 5G Networks: Eindhoven 5G Brainport Testbed

Abstract: 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.

Supervised Machine Learning Techniques for Quality of Transmission Assessment in Optical Networks

Abstract: We propose and compare a number of machine learning models to classify unestablished lightpaths into high or low quality of transmission (QoT) categories in impairment-aware wavelength-routed optical networks. The performance of these models is evaluated in long haul communication networks and compared to previous proposals. Results show that, especially random forests and bagging trees approaches, significantly reduce the required computing time to classify the QoT of a given lightpath, while accuracy remains around 99.9%.

An Optical Wireless Communication Based 5G Architecture to Enable Smart City Applications

Abstract: The main objective of smart city is to enable efficient management of resources using advanced information and communication capabilities of the telecommunication infrastructure which requires seamless connectivity between the different components composing the city infrastructure and users. Current communication approaches in smart cities applications are based on radio frequency (RF) transmission technology which cannot satisfy data rate demand and transmission delay requirement of these applications. The 5G mobile communication network is being proposed as the core technology that is able to implement the smart city paradigm. In this context, optical wireless technologies are envisioned by many research communities as a promising solution to provide the needed broadband connectivity and satisfy the quality of service (QoS) requirements of users. The main objective of this paper is to propose a communication architecture that can seamlessly integrate the optical wireless technology in the 5G communication networks to enable smart city applications deployment. The proposed network architecture is structured into three layers integrating different optical wireless technologies. More precisely, we study the deployment of optical access points (OAPs) in specific locations of interest in the city (such as road intersections, lighting systems, and signalling equipment) in order to enhance the performances of the sensing, tracking, and communication services. Furthermore, we propose to integrate a backbone network composed of optical access points which is structured into a grid topology to enable communication using free space optical (FSO) transmission. The optical access points are expected to implement label based all-optical switching capability to forward traffic between optical access points. Moreover, access control using OFDMA are investigated to distribute connectivity between users belonging to the same attocell. Finally, issues related to cell dimensioning, handover management and technology integration are discussed and some alternatives are proposed.

Planning of 5G C-RAN with Optical Fronthaul: A Scalability Analysis of an ILP Model

Abstract: We focus on cross-layer optimization of 5G radio-optical communication networks (5G-RONs) that implement a centralized/cloud radio access network (C-RAN) architecture with the optical fronthaul network assuring the connectivity between remote radio heads (RRHs) and centralized base-band units (BBUs). In particular, we study a 5G-RON planning problem, which concerns cost-effective placement of RRHs, BBUs, and optical fibers, with the requirement to achieve certain level of population coverage. The problem is formulated as an integer linear programming (ILP) problem. The main goal of this work is to assess the difficulty of practical solving ILP models in 5G-RONs scenarios. Our scalability analysis of ILP modeling is performed in terms of different network dimensions, various RRH coverage radius, as well as under consideration of problem extensions related to signal latency requirements. The obtained numerical results indicate on the complexity of solving the ILP model even for moderate size networks, and motivate for further studies in 5G-RON optimization.

Optical Fronthaul Options for Meeting 5G Requirements

Abstract: New functional splits for the 5G Radio Access Network have been identified so that fronthaul will no longer need to transport sampled time-domain waveforms. However, the different functional split points place differing demands on the fronthaul transport, while also posing different constraints to 5G techniques, such as massive MIMO. According to these conflicting demands, it is likely that in many cases, more than one split point may be needed in the same radio access network.

Experimental Evaluation of Passive Optical Network Based Data Centre Architecture

Abstract: Passive optical networks (PON) technology is increasingly becoming an attractive solution in modern data centres as it provides energy efficient, high capacity, low cost, scalable and flexible connectivity. In this paper we report the implementation of a PON based data centre architecture that provides high resilience and high speed interconnections by providing alternative communication routes between servers in different racks. Each rack is divided into several groups of servers and connects to other racks and the Optical Line Terminal (OLT) through a set of server that acts as relay servers. We implement the switching and routing functionalities within servers using 4×10GE Xilinx NetFPGA, and demonstrate end-to-end communication using IP cameras live video streaming over up to 100 km optical connections through WDM nodes and the PON network.

Recent Developments in Service Function Chaining (SFC) and Network Slicing in Backhaul and Metro Networks in Support of 5G

Abstract: In this invited paper we examine the role of Service Function Chaining (SFC) and Network Slicing in providing support for emerging 5G services as data is carried across backhaul and metro networks.The way in which backhaul and metro networks are managed and operated affects the ability of those networks to support a wide range of services that will be enabled by 5G connectivity. Those services will place exacting demands on the bandwidth, delay bounds, and jitter delivered to users, but may vary significantly over relatively short time periods. SFC and Network Slicing offer opportunities for software-driven coordination of network resources to marshal them so as to best deliver the network behaviour that will support the demands of the services.We present the latest proposals towards standardisation of SFC and Network Slicing in the Internet Engineering Task Force (IETF) and discuss how these concepts are applied in optical networks through the Metro-Haul project.

A Proactive Restoration Strategy for Optical Cloud Networks Based on Failure Predictions

Abstract: Failure prediction based on the anomaly detection/forecasting is becoming a reality thanks to the introduction of machine learning techniques. The orchestration layer can leverage on this new feature to proactively reconfigure cloud services that might find themselves traversing an element that is about to fail. As a result, the number of cloud service interruptions can be reduced with beneficial effects in terms of cloud service availability.Based on the above intuition, this paper presents an orchestration strategy for optical cloud networks able to reconfigure vulnerable cloud services (i.e., the ones that would be disrupted if a predicted failure happens) before an actual failure takes place. Simulation results demonstrate that, with a single link failure scenario, proactive restoration can lead to up to 97% less cloud services having to be relocated. This result brings considerable benefits in terms of cloud service availability, especially in low load conditions. It is also shown that these improvements come with almost no increase in the cloud service blocking probability performance, i.e., resource efficiency is not impacted.

Optimal Constellation Shaping in Optical Communication Systems

Abstract: In optical communications systems, Shannon limit can be closely approached by properly chosen constellation shaping schemes. Both probabilistic shaping (PS) and geometric shaping(GS) can be applied to M-ary quadrature amplitude modulation (QAM) to obtain the shaping gain. In this invited paper, mutual information (MI) is used as a metric to analyze the performances of regular/GS/PS-8/16QAM formats. In a linear amplified spontaneous emission (ASE) noise dominated system, our numerical results show that the MI performances of the GS-8/16QAM are better than that of regular 8/16QAM and PS-8/16QAM. Then we experimentally compare the performances of regular/GS/PS-16QAM formats over a 100km fiber transmission link. Our numerical and experimental results are very useful in selection of the optimal constellation shaping for a given optical communication system.

Metro-Haul: SDN Control and Orchestration of Disaggregated Optical Networks with Model-Driven Development

Abstract: SDN solutions for optical transport networks are often associated to single-vendor optical domains, managed as single entities, in a deployment model that is commonly referred to as fully aggregated. Such controllers do export and expose interfaces for the limited control of abstracted resources and operations via north-bound interface (NBI) to operations/business support systems (OSS/BSS), but such APIs are often vendor specific and internal control aspects related to provisioning, monitoring and resource management remain proprietary and not disclosed.Disaggregation of optical networks refers to a deployment model of optical systems, by composing and assembling open, available components, devices and sub-systems. This disaggregation is driven by multiple factor (the mismatch between the needs of operators and the ability to deliver adapted solutions by vendors or the increase in hardware commoditization) and disaggregated networks are an excellent use case for open and standard interfaces, showing the benefits of a unified, model-driven development.In this paper, we address the SDN control of a disaggregated optical networks and its role in a wider Control Management and Orchestration (COM) architecture to offer ETSI NFV Network Services in a metropolitan infrastructure, characterized by multiple geographical locations and NFVI. We highlight the main use cases and the implemented extensions to the ONOS Platform for the aforementioned purpose. We detail the design of the controller (core systems and applications); the approach taken for model driven-development, including the YANG modelling language for the different optical devices and the NETCONF protocol to remotely configure the devices and, finally, the experimental validation of the approach and implementation with selected scenarios.

Probabilistically Shaped 8-PAM Suitable for Data Centers Communication

Abstract: We study non-uniform 8-PAM signaling schemes, based on Maxwell-Boltzmann and exponential source distributions, as candidates suitable for data centers’ communications. We evaluate mutual information of these schemes against corresponding uniform 8-PAM scheme, for different parameters of source distributions. The properly chosen variable parameters for different SNR-regions allows us to closely approach Shannon limit, and to significantly outperform the corresponding uniform counterpart. We demonstrate that LPDC-coded 8-PAM with exponential distribution outperforms the LDPC-coded 8-PAM with uniform distribution of the same achievable information rate by 1.8 dB, and this improvement is comparable to that obtained from mutual information calculations.

Enabling Data Analytics and Machine Learning for 5G Services within Disaggregated Multi-Layer Transport Networks

Abstract: Recent advances, related to the concepts of Artificial Intelligence (AI) and Machine Learning (ML) and with applications across multiple technology domains, have gathered significant attention due, in particular, to the overall performance improvement of such automated systems when compared to methods relying on human operation. Consequently, using AI/ML for managing, operating and optimizing transport networks is increasingly seen as a potential opportunity targeting, notably, large and complex environments.Such AI-assisted automated network operation is expected to facilitate innovation in multiple aspects related to the control and management of future optical networks and is a promising milestone in the evolution towards autonomous networks, where networks self-adjust parameters such as transceiver configuration.To accomplish this goal, current network control, management and orchestration systems need to enable the application of AI/ML techniques. It is arguable that Software-Defined Networking (SDN) principles, favouring centralized control deployments, featured application programming interfaces and the development of a related application ecosystem are well positioned to facilitate the progressive introduction of such techniques, starting, notably, in allowing efficient and massive monitoring and data collection.In this paper, we present the control, orchestration and management architecture designed to allow the automatic deployment of 5G services (such as ETSI NFV network services) across metropolitan networks, conceived to interface 5G access networks with elastic core optical networks at multi Tb/s. This network segment, referred to as Metro-haul, is composed of infrastructure nodes that encompass networking, storage and processing resources, which are in turn interconnected by open and disaggregated optical networks. In particular, we detail subsystems like the Monitoring and Data Analytics or the in-operation planning backend that extend current SDN based network control to account for new use cases.

Encapsulation Techniques and Traffic Characterisation of an Ethernet-Based 5G Fronthaul

Abstract: This paper first overviews how, in the 5G Next Generation Radio Access Network (NG-RAN), the Next generation NodeB (gNB) functions are split into Distributed Unit (DU) and Central Unit (CU). Then it describes the proposed fronthaul transport solutions, such as Common Packet Radio Interface (CPRI), eCPRI, IEEE P1914.3 and their relationship with the Ethernet protocol. Finally, a characterisation of the traffic generated by the fronthaul is presented. Such characterisation may guide in the selection of the right network for fronthaul transport.

The Synopsys Software Environment to Design and Simulate Photonic Integrated Circuits: A Case Study for 400G Transmission

Abstract: To afford the dramatic intra- and inter-datacenter traffic growth envisioned for the decade, the IEEE P802.3bs Task Force is targeting the standardization of 200 Gb/s and 400 Gb/s Ethernet. Transceivers adopting this standard will need to substantially reduce cost and power consumption with respect to similar equipment that are currently the state-of-the-art for long-haul networks. The most promising solution for such a challenging objective is offered by integrated photonics, a state-of-the-art technology capable of providing high-speed components and large-scale circuits with high-volume, high-yield, and low-cost manufacturing.Synopsys proposes an integrated software (SW) environment capable of assisting with virtual prototyping and testing of the circuit before proceeding with the physical implementation. It is the integration of the OptSim Circuit tool for schematic-driven photonic integrated circuit (PIC) design, with the PhoeniX OptoDesigner photonic layout tool, and the RSoft Photonic Component Design Suite, thus providing a single modeling solution at the circuit, layout, and device levels of abstraction. In this work, we first present this integrated SW environment, focusing on its potential and usability. Then, we use the APSUNY Silicon Photonics Integrated Circuit Process Design Kit (PDK) library sponsored by AIM Photonics to model a PM-16QAM transceiver with a 400G transmission data rate.