Showing papers on "Optical Transport Network published in 2021"

Coexistence of quantum key distribution and optical transport network based on standard single-mode fiber at high launch power.

Abstract: There is an increasing demand for multiplexing of quantum key distribution with optical communications in single fiber in consideration of high costs and practical applications in the metropolitan optical network. Here, we realize the integration of quantum key distribution and an optical transport network of 80 Gbps classical data at 15 dBm launch power over 50 km of the widely used standard (G.652 Recommendation of the International Telecom Union Telecom Standardization Sector) telecom fiber. A secure key rate of 11 Kbps over 20 km is obtained. By tolerating a high classical optical power up to 18 dBm of 160 Gbps classical data on single-mode fiber, our result shows the potential and tolerance of quantum key distribution being used in future large capacity transmission systems, such as metropolitan area networks and data centers. The quantum key distribution system is stable, practical, and insensitive to the polarization disturbance of channels by using a phase coding system based on a Faraday–Michelson interferometer. We also discuss the fundamental limit for quantum key distribution performance in the multiplexing environment.

Energy-Efficient DU-CU Deployment and Lightpath Provisioning for Service-Oriented 5G Metro Access/Aggregation Networks

Abstract: To accommodate ever-growing mobile data and heterogeneous 5G services, considerable challenges have emerged to stimulate new design principles on radio access networks (RAN). Advanced functional splits are then introduced to divide baseband unit (BBU) into two new entities, i.e., distributed unit (DU) and central unit (CU), that DU-CU can be co-located or separated into different processing pools (PP) honoring service requirements. Then, the optical transport network evolves towards a more flexible architecture to support agile DU-CU deployment (i.e., alterable DU-CU locations). However, this agile DU-CU deployment without an effective management strategy may lead to the activation of many unnecessary PPs and lightpaths in the network infrastructure that results in low energy efficiency. Moreover, this problem will be continuously amplified with network scale expansion, which becomes one of the operator's major concerns for OPEX reduction. Thus, in this paper, we are dedicated to solving this problem through turning network devices from “always on” to “on-demand on” pattern to support energy-efficient DU-CU deployment and lightpath provisioning. To this end, we propose a mixed-integer linear programming (MILP) model and auxiliary graph-based heuristic to minimize the power consumption of reconfigurable add/drop multiplexer, Ethernet switch, optical transponder, PP, and DU-CU processor. We analyze the power consumption under different 5G services (i.e., eMBB, URLLC, and mMTC) from a latency perspective in both small-scale and large-scale networks. Moreover, our strategies can also be applied with adjustable deployment that adapts to time-varying user traffics, which reduces power by over 14% compared to conventional static deployment. Our analyses can help provide insights into the modeling and designing of energy-efficient DU-CU deployment and lightpath provisioning in 5G.

Optical service unit (OSU)-based next generation optical transport network (NG OTN) technology and verification

Abstract: With the development of transmission technologies, optical transport network (OTN) has evolved from a digital encapsulation technology to a network technology that supports multi-service transport. As the OTN gradually expands to the edge of the metropolitan area network (MAN) and enterprise users have higher quality requirements on bandwidth and service security, more and more private line services are provided via OTN network. Therefore, the OTN container is transformed from an optical data unit (ODU) to an optical service unit (OSU). The OTN industry has studied several OSU technologies to fit the development trends of NG OTN, aiming at transporting 2 Mbit/s to 100 Gbit/s constant bit rate (CBR) services and Ethernet services with high efficiency and more flexibilities, as well as reducing OTN network deployment and operation and maintenance (O&M) costs. In this work, several key technologies in NG OTN are introduced including NG OTN technical architecture, OSU frame format, client mapping and OSU multiplexing. Based on these technologies, we (China Mobile) took the lead in conducting the industry's first NG OTN test in Qingdao, which verified the service transport capability and lower latency performance of OSUs and promoted the maturity of the NG OTN industry chain.

Packet Optical Transport Network Slicing with Hard and Soft Isolation

Abstract: Network operators have been dealing with the necessity of a dynamic network resources allocation to provide a new generation of customer-tailored applications. In that sense, Telecom providers have to migrate their BSS/OSS systems and network infrastructure to more modern solutions to introduce end-to-end automation and support the new use cases derived from the 5G adoption and transport network slices. In general, there is a joint agreement on making this transition to an architecture defined by programmable interfaces and standard protocols. Hence, this paper uses the iFusion architecture to control and program the network infrastructure. The work presents an experimental validation of the network slicing instantiation in an IP/Optical environment using a set of standard protocols and interfaces. The work provides results of the creation, modification and deletion of the network slices. Furthermore, it demonstrates the usage of standard communication protocols (Netconf and Restconf) in combination with standard YANG data models.

Optical Transport Network to support Digital Communications

Abstract: The objective of this work is to propose a solution to the problem of the lack of telecommunication services, with adequate quality of service and coverage, in the town of Choclococha, Huancavelica-Peru. For this purpose, the design and evaluation of an optical link as a backbone network and a wireless access network is presented. It is an applied and experimental research in which performance parameters were evaluated. The independent variable is the optical transport network and the dependent variable is data communication. The latter is defined by two indicators: throughput and signal reception power at the users. Both indicators were measured in a sample of the population, obtaining results that were validated with respect to the expected values according to specifications and regulations. Thus, the measured throughput exceeds the 40% data rate guaranteed by the telecommunications operator. As for the reception power, it exceeds the sensitivity level of the receiving equipment. Therefore, it is concluded that the proposed solution supports communications with optimum speed and coverage.

Transmission Delay in Optical Fiber Communication System of Power Transmission and Transformation

Abstract: An OTN optical service unit (OSU) solution uses dedicated DM bytes for delay information transmission. The NMS can visualize network delay in real time, which is better than the manual delay evaluation method of SDH. The OSU defines the timestamp byte for the transmission clock at the physical layer. The physical-layer pre-processing is not required when the IP-based IEEE 1588v2 protocol is used, and the natural time transmission protocol is formed. The precision of the OSU is higher than the SDH delay estimation mode. In addition, the clock transmission protocols of different vendors are consistent and interconnected. Compared with SDH and IP networks, the OTN OSU networks are more suitable for WAN interconnection of the power production services and the time-sensitive network services.

Uncertainty Analysis for Failure Prediction in Optical Transport Network Using Bayesian Neural Network

Abstract: A Bayesian neural network-based uncertainty analysis technique is proposed for failure prediction in optical transport network, which can not only achieve F1-score up to 99.5%, but also give an uncertainty quantification for the prediction results.

Proof-of-Concept of the Time and Spectral Optical Aggregation Network

Abstract: In this article, we present the proof of concept (PoC) of the time and spectral optical aggregation (TISA) approach that allows a better filling of the time and spectral resources of an optical transport network. Some innovative solutions have been implemented, such as a new and fast tunable laser that permits to color the bursts sent in the TISA network, as well as their transmission with both DP-QPSK and DP-16QAM coherent multi-band (MB) OFDM formats. BER versus OSNR measurements have been achieved showing less than 1-dB penalty in back-to-back or after transmission. The tolerance of bursts against frequency mismatch occurring between the transceiver and the optical filter that extracts a sub-band inside the MB-OFDM signal has also been evaluated, and ∼1.5 GHz tolerance has been measured for bursts of ∼6.7 GHz bandwidth. Furthermore, in order to mitigate the transients in the coherent receiver that faces alternatively the presence or absence of signal, a novel channel estimator based on a sliding window has been introduced. Its efficiency and performance has been experimentally validated, and its ability to suppress the error threshold of the BER versus OSNR curves has been demonstrated. By the experimental proof of concept delivered here, the ability of the TISA network to perform with a good level of performance the transparent routing and sub-wavelength aggregation/disaggregation in the time and spectral domains simultaneously has been established. Beyond the important and crucial aspect of the optimal filling of the optical resources, our PoC demonstrate the ability of the TISA approach to push the flexibility of an optical transport network at its limit while allowing a cost and power consumption limitation obtained by the removal of costly and power-hungry optical-electrical-optical regenerators.

A theoretical study of subcarrier-wave quantum key distribution system integration with an optical transport network utilizing dense wavelength division multiplexing

Abstract: In this paper we study the performance of subcarrier-wave quantum key distribution (SCW QKD) in the presence of classical channels of optical transport network utilizing dense wavelength division multiplexing (DWDM). We consider the impact of spontaneous Raman scattering noise as well as the four-wave mixing and channel isolation efficiency. We calculate quantum bit error rate as well as the secure key generation rate of SCW-QKD protocol for different parameters of DWDM system and quantum channel allocations. Our calculations show, that quantum channel allocation at the wavelength of 1310 nm is preferable to allocation at C-band due to lower nonlinear noise, despite fiber’s larger attenuation at this wavelength.

Security-Aware Planning of Packet-Over-Optical Networks in Consideration of OTN Encryption

Abstract: The fast development of cloud computing and Big Data applications has promoted virtualization technologies such as network function virtualization (NFV), which in turn dramatically increased the amount of sensitive data being transmitted over the optical networks for datacenter interconnections (DCIs). To ensure the physical-layer security in DCIs, people have developed optical transport network (OTN) encryption technologies, i.e., leveraging high-speed encryption cards (ECs) to encrypt OTN payload frames. Although experimental studies have confirmed the benefits of ECs in terms of line-speed processing, low latency, and small encryption overhead, the problem of how to utilize them to build a secure packet-over-optical network with high cost-effectiveness has not been explored yet. In this paper, we study how to realize cost-effective and security-aware multilayer planning in a packet-over-optical network that covers both trusted and untrusted zones, in consideration of OTN encryption. We first formulate an integer linear programming (ILP) model to minimize the total capital expenditure (CAPEX) of the multilayer planning, which includes the costs of OTN linecards (LCs), ECs, and bandwidth resources, and solve the optimization exactly. Then, we prove the $\mathcal {NP}$ -hardness of the multilayer planning, and to reduce the time complexity, we propose a column generation (CG) model and design a more time-efficient approximation algorithm based on it. Our simulation results confirm the performance and advantages of our CG-based proposal, i.e., it is much more time-efficient than solving the ILP directly, and outperform the existing heuristic in terms of total CAPEX and costs of used LCs and ECs.

Optical Front/Mid-haul with Open Access-Edge Server Deployment Framework for Sliced O-RAN

Abstract: The fifth-generation of mobile radio technologies is expected to be agile, flexible, and scalable while provisioning ultra-reliable and low-latency communication (uRLLC), enhanced mobile broadband (eMBB), and massive machine type communication (mMTC) applications. These are implemented by adopting cloudification, network function virtualization, and network slicing techniques in open-radio access network (O-RAN) architecture where remote radio heads (RRHs) are connected to dis-aggregated virtual base-band units (BBUs), i.e., radio unit (RU), distributed unit (DU), and centralized unit (CU) over front/mid-haul interfaces. However, cost-efficient solutions are required for designing front/mid-haul interfaces and time-wavelength division multiplexed (TWDM) passive optical network (PON) appears as a potential candidate. Therefore, in this paper, we propose a framework for the optimal placement of RUs based on long-term network statistics and connecting them to open access-edge servers for hosting the corresponding DUs and CUs over front/mid-haul interfaces while satisfying the diverse QoS requirements of uRLLC, eMBB, and mMTC slices. In turn, we formulate a two-stage integer programming problem and time-efficient heuristics for users to RU association and flexible deployment of the corresponding DUs and CUs. We evaluate the O-RAN deployment cost and latency requirements with our TWDM-PON-based framework against urban, rural, and industrial areas and show its efficiency over the optical transport network (OTN)-based framework.

Optical Transmission Network Evolution Scheme of VC-OTN

Abstract: With the evolution of operator network, the optical transmission network (OTN) technology which integrates the cross-function of Virtual Container (VC) has become a hot research topic. In this paper, the application scheme of VC-OTN technology including network structure planning, network evolution steps and protection scheme in transmission network is proposed. The pilot project proves that the proposed scheme can significantly guide the operator network construction.

Extinction Ratio and the Fiber Optic Transmission Networks

Abstract: In the fiber optic communication network for example,- FTTH, EPON, NBN, OTN and so on, the most important components are fiber length between transmitter and receiver point. So, to make, cheap and meaningful communication through optical fiber it must be required to calculate how and what amount of signal is transmitted with the given length of the fiber. Finally, it is said that the optical fiber network have several limitations like extension ratio. So, it is necessary to investigate its affect on the performance of the Optical Network. This research is based on simulation by OptiSystem 0.17 on the basis of Dense wavelength division multiplex (DWDM) technology, Erbium Doped Fiber Amplifier (EDFA), dispersion Compensating Fiber (DCF) and single mode fiber of length 50–100 km.

Smart Grid Communication System based on OTN Technology

Abstract: With the rapid development of society, the social demand for electricity is increasing day by day, which puts forward higher requirements for the power communication network, which makes the application effect of optical transmission network technology gradually significant. In view of the characteristics and functions of optical transmission network (OTN), continuous extension and expansion are carried out to realize the gradual integration of smart grid communication system. Based on this, this paper studies the smart grid communication system based on OTN technology. Based on the analysis of the characteristics and key technologies of OTN technology, combined with the communication requirements of smart grid communication system, the specific application of OTN technology in smart grid communication system is studied, and the application of OTN technology in power communication network is taken as the experimental group Finally, the application of OTN technology in power communication network is explored. The results show that the average score of the experimental group is 3.3 higher than that of the control group in terms of service adaptability, service demand satisfaction and intelligent level of communication network. Therefore, it is very necessary to establish the backbone optical transmission network of power communication by using OTN technology, so as to provide guarantee for the safe and stable operation of smart grid.

Efficient Make-Before-Break Layer 2 Reoptimization

Abstract: Optical multilayer optimization periodically reorganizes layer 0-1-2 network elements to handle both existing and dynamic traffic requirements in the most efficient manner. This delays the need for adding new resources in order to cope with the evolution of the traffic, thus saving CAPEX. The focus of this paper is on Layer 2, i.e., on capacity reoptimization at the optical transport network (OTN) layer when routes (e.g., LSPs in MPLS networks) are making unnecessarily long detours to evade congestion. Reconfiguration into optimized routes can be achieved by re-defining the routes, one at a time, so that they use the vacant resources generated by the disappearance of services using part of a path that transits the congested section. To maintain the Quality of Service, it is desirable to operate under a Make-Before-Break (MBB) paradigm, with the minimum number of reroutings. The challenge is to determine the best rerouting order while minimizing the bandwidth requirement. We propose an exact and scalable optimization model for computing a minimum bandwidth rerouting scheme subject to MBB in the OTN layer of an optical network. Numerical results show that we can successfully apply it on networks with up to 30 nodes, a very significant improvement with respect to the state of the art. We also provide some reoptimization analysis in terms of the bandwidth requirement vs. the number of reroutings.

Method and device for service processing in optical transport network, and system

Abstract: Disclosed in the present application are a method and device for processing service data in an optical transport network (OTN), and a system. The method for processing service data comprises: after service data is acquired, mapping the service data into an optical service unit (OSU) frame, the OSU frame comprising an overhead subframe and a data subframe, the overhead subframe being used for carrying overhead information, and the data subframe being used for carrying the service data; mapping the OSU frame into multiple payload blocks of an OTN frame, the OSU frame corresponding to an identifier of the service data; and sending the OTN frame. The described processing method uses a new frame structure and defines a set of corresponding service processing procedures, the proportion of overhead is relatively low, and the carrying efficiency of an OTN frame can be improved.

Performance Evaluation of RWA Algorithms in ASON Resiliency Mechanisms for Better Resource Utilization and Service Performance Quality

Abstract: This research work proposes a solution to employ a Routing and Wavelength Assignment (RWA) algorithm that can utilize network resources efficiently with better service performance quality in dynamic Automatically Switched Optical Network (ASON) service provisioning. It conducts blocking probability and network availability comparison simulations for the widely used adaptive RWA algorithms of Shared Risk Group (SRG)-Disjoint Aware First-Fit Routing, Alternate Routing, Least Congested Routing and Load Sharing Routing algorithms coordinated with First-Fit wavelength assignment algorithm, in 1+1 Dedicated Path Protection (DPP) and Restoration. The simulations are conducted on Net2Plan simulation tool using ethio telecom’s Addis Ababa Metro Backbone Optical Transport Network (OTN) as reference topology. The results show that, for both Protection and Restoration, the Alternate Routing and Least Congested Routing algorithms are competently better in blocking probability performance. The network availability of the Alternate Routing is found to be better in both protection and restoration schemes.

Method for removing static differential delays between signals transported over an optical transport network

Abstract: A method for removing static differential delays resulting from an independent transport of the client signals of a client signal bundle through an optical transport network, OTN, which comprises OTN mappers mapping received client signals to ODU signals transported to OTN demappers demapping received ODU signals to client signals, wherein a process slave, PS, at the OTN mapper end of said OTN network supplies continuously or in response to a received request information about timing relations between the client signals of said client signal bundle to a process master, PM, at the OTN demapper end of said OTN network used by the process master, PM, to remove the static differential delays between the client signals of the respective client signal bundle

Power-Aware Routing in Optical Transport Networks With Physical Layer Impairment Constraints

Abstract: Due to the growth in data traffic volume and diversification of applications that use telecom network infrastructure, more power consuming telecommunication network equipments have been deployed. This scenario has led to an increase in the power consumption of the sector. In order to overcome this problem, stakeholders are striving to come up with ways to minimize this power consumption. In this work, a sleep mode operational strategy which takes the Physical Layer Impairment (PLI) and power loss/attenuation is proposed and an Integer Linear Programming (ILP) formulation is given. An implementation of the approach is carried out using GLPK optimizer and TOTEM toolbox simulation environments and results analyzed taking two Ethio Telecom backbone Optical Transport Network (OTN) segments. These optimizations & simulations help to analyze the impacts on Quality of Service (QoS) of applying this approach in addition to its main goal of power consumption minimization. Results show that a power saving of upto 51% for Addis Ababa backbone OTN and 44% for North-East backbone OTN can be achieved at maximum link utilization thresholds of 70% and 50% respectively. Link utilization constraint is used to ensure network QoS is maintained.

Network Management with Reliance on Topology and Generating Paths through the Network Layers

Abstract: For applications to acquire new organization semantics, overlay networks reflect a scalable and deployable solution, however, they experience the ill effects of certain proficiency concerns. Two new natives for execution in the organization layer are proposed to effectively help overlay networks. In nearby routers, Packet Reflection permits end hosts to demand cut off steering and replication. Path Painting enables several ends to be painted. Hosts to decide the location of their various paths, In order to allow overlay, the rendezvous point meets Constructing topology. Incrementally, both primitives are Implementable. In general, techniques are defined to dynamically determine a logical network topology to transport network traffic more efficiently over a physical topology based on end-to-end network traffic demands and network characteristics of the optical transport network (OTN). The methods can be used to meet the demands of network traffic imposed on a multi-layer network with a base transport layer and a layer of logical or overlay Internet Protocol (IP) routed on the transport layer. We compare and evaluate, to achieve justice, Different targets of traffic advancement for topology improvement. The use of neural networks for the simulation of nonlinear relationships. By using neural organizations, we intend to forestall any shamefulness, for example, Like dismissing direct guess. Our work also indicates which In network optimization, functions are essential for machine learning. Our methodology is partly in harmony with the previous work, and we The best performing optimization target is to conclude the delay.

Demonstration of ML-aided Impairment-aware L0 Path Computation in Fully Disaggregated Multi-vendor Optical Transport Networks

Abstract: We demonstrate an online impairment-aware L0 path computation capability leveraging a machine learning model to recommend the most appropriate path and optical parameters combination for a connectivity service request in the fully disaggregated multi-vendor optical transport network.

Service signal processing method and device

Abstract: The embodiments of the present application provide a service signal processing method. In said method, an optical network unit (ONU) receives a service signal, and maps the service signal to a flexible optical service unit frame. An ONU sends a first passive optical network transmission convergence frame to an optical line termination (OLT), a flexible optical service unit frame being packaged in the first passive optical network transmission convergence frame, and the flexible optical service unit frame being used for carrying a service signal in a passive optical network (PON) and an optical transport network (OTN). By means of the present application, a flexible optical service unit frame can not only be transmitted in a PON, but also be transmitted in an OTN, the ONU and the OLT do not need to parse a service signal, and thus the time delay can be reduced.

Rethinking of Optical Transport Network Design for 5G/6G Mobile Communication

Abstract: Driven by the increasing use of emerging smart mobile applications, mobile technology is continuously and rapidly advancing towards the next generation communication systems such as 5G and 6G. However, the transport network, which needs to provide low latency and reliable connectivity between hundreds of thousands of cell sites and the network core, has not advanced at the same pace. This article provides insight into how we can solve the fundamental challenges of implementing cost-optimal transport and 5G and beyond mobile networks simultaneously while satisfying the network and user requirements irrespective of the radio access network's architecture.

Wideband PPLN-based optical parametric amplifiers for scalable optical transport network

Abstract: This paper reviews the wideband optical parametric amplifiers based on periodically poled LiNbO 3 (PPLN) waveguides for scalable optical transport network. The achievable bandwidth over 10 THz is promising to offset capacity crunch in today’s network.

Optical transport network alarm processing method and apparatus, terminal device, and storage medium

Abstract: The present disclosure provides an optical transport network alarm processing method and apparatus, a terminal device, and a storage medium. The processing method comprises: performing hierarchical ordering on optical transport networks according to the relationships between customer layers and service layers; defining grades of alarm levels in the optical transport networks from low to high levels according to the network levels obtained by hierarchically ordering, each alarm level corresponding to a network level; and when an alarm is generated, checking whether there is an alarm of a higher level than the current alarm in the optical transport networks, and if yes, blocking the current alarm, or otherwise, reporting the current alarm.