Gigabit-capable Passive Optical Network Research Articles

BR-FRL: A Belief Rule-Based Fault Recognition and Location Model for Bus Network Systems

For a control system with bus network topology, it is significant while difficult to accurately recognize and locate the fault of transmission medium. The reason is that the occurrence of one fault can lead to the abnormality of multiple terminal nodes. How to use these abnormal signals to realize effective fault recognition and fault location is the key to solving the problem. Inspired by the manual inference in engineering practice, this paper proposes a belief rule-based fault recognition and location model (BR-FRL) for transmission medium in bus network systems. The core idea is fault location based on the results of fault recognition. To adapt to the flexible expansion of bus topology, the designed BR-FRL model has self-organization characteristics. The highlights of this paper include three aspects: 1) The progressive reasoning of fault recognition and location based on belief rules is realized in one model; 2) A new model architecture is proposed, which integrates the belief rules, the group method of data handling, and the cautious conjunctive rule (CCR); 3) The parameter learning based on stochastic gradient descent is applied to BR-FRL, and the sensitivity analysis of evidence weight in CCR of BR-FRL is performed. The effectiveness of BR-FRL is verified by an experiment of gigabit-capable passive optical network.

Deep Infinite Mixture Models for Fault Discovery in GPON-FTTH Networks

Fault diagnosis in telecommunication networks requires extensive expert knowledge and is key to efficient network operations and high service availability. Specifically, discovering and identifying new faults occurring in the network is a challenging task. Some dominant methods in industry are based on expert systems or Bayesian networks. Both of these methods require considerable expert knowledge and time resources to construct and maintain the diagnosis system. In this paper, we propose a data driven approach for the clustering and identification of new faults, based on existing knowledge, using neural networks and infinite mixture models. In our approach deep infinite mixture models are capable of extracting interesting features from labeled data, which are then leveraged in the clustering process to identify new relevant faults in unlabeled data. We apply our method to real operational data from Fiber-to-the Home services based on Gigabit-capable Passive Optical Networks. We show that our approach can be trained end-to-end, and allows to identify and interpret new faults.

GPON PLOAMd Message Analysis Using Supervised Neural Networks

This paper discusses the possibility of analyzing the orchestration protocol used in gigabit-capable passive optical networks (GPONs). Considering the fact that a GPON is defined by the International Telecommunication Union Telecommunication sector (ITU-T) as a set of recommendations, implementation across device vendors might exhibit few differences, which complicates analysis of such protocols. Therefore, machine learning techniques are used (e.g., neural networks) to evaluate differences in GPONs among various device vendors. As a result, this paper compares three neural network models based on different types of recurrent cells and discusses their suitability for such analysis.

Construction and practice of all-optical campus network based on gigabit-capable passive optical networks

Regarding to the disadvantages of the traditional three-tier campus network, we discuss the construction of all-optical campus network based on gigabit-capable passive optical networks (GPON) technology to meet the needs of network environment for intelligent campus. At the same time, the design of the interconnections between the three campuses of Shenzhen University is introduced. And taking the GPON networking case of the Lihu Campus as an example, we discusse the problems related to the implementation process of all-optical campus network.

Expand or Oversize? Planning Internet Access Network in a Demand Growth Scenario

Internet network design specialists are looking for technologies and strategies to deliver network service under increased demand conditions. The choice of strategies is based on applying optimization and decision-making methods to select the most appropriate cable network design considering criteria established by the problem definition. However, this definition is itself a decision problem that has not received analysis in the literature. In particular, one of the most important questions is the necessity to define an expansion strategy. The first alternative (expansion) is to design a network to serve consumers with Internet demand equal to or greater than the predefined one to expand the network annually to serve consumers that reach the predefined Internet speed. The second alternative (oversizing) is to design a network to serve consumers with future Internet demand (after 5 years) at or above that the predefined one. Considering this, the objective of this research is to define the most advantageous strategy of expansion planning to attend a 5 years forecasted Internet demand, considering: (1) the possibility of utilizing a Gigabit-capable Passive Optical Network technology; (2) the application of the minimal Steiner tree and Dijkstra algorithms in planning procedures; (3) the influence of economic and technological factors on the demand forecast; (4) the aggressive, moderate, and conservative scenarios in decision-making. The results show that the over-dimensioning strategy reduces network investment by between 30 and 41%, but that this reduction does not always lead to a market investment ratio higher than that observed in the expansion strategy.

Perancangan Jaringan Fiber to the Home (FTTH) pada Perumahan di Daerah Urban (Fiber to the Home (FTTH) Network Design at Housing in Urban Areas)

The evolution of communication network comes from the need for users to stay connected anytime and anywhere. Modernization of the network continues to be done to increase bandwidth capacity in order to obtain an increase in multimedia services, especially in urban areas. Of various transmission media, optical fiber is the best choice to support reliable communication networks. One of the optical fiber communication technologies is Fiber to the Home (FTTH). This study proposes FTTH network design with Gigabit Capable Passive Optical Network (GPON) technology aimed at housing in urban areas. The design uses aerial and duct-aerial cabling systems. The design analysis is carried out based on the parameters of the link power budget, rise time, Bit Error Rate (BER), components and costs required. The value of the power budget link for the uplink and downlink are -22.792 dBm and -23.120 dBm. The rise time value for uplink and downlink are 0.256 ns and 0.258 ns, while the BER value is 14.628 x 10-12. The calculation results show that the design meets the required parameters, hence, the proposed network can be implemented. For the cost components required by the aerial system, it is 11.56% less than of the ductaerial sistem.

A Centralized Gigabit Passive Optical Network Fault Monitoring Using Fiber Bragg Grating Sensor

In this paper, an improved technique for a centralized fault monitoring and detection in Gigabitcapable Passive Optical Network using fiber Bragg grating sensor is proposed. The technique detects fault once it occurs at the vulnerable locations in the fiber optic distribution link by the proposed Fiber Bragg Grating devices. The scheme uses an amplified Erbium Doped Fiber Amplifier monitoring signal in the C-band and a uniform Fiber Bragg Grating with different Bragg wavelengths and reflectivities as the branch identifiers in the network. The reflected signal from the optical sensor is analyzed at the Optical Line Terminal in the Central Office by an Optical Spectrum Analyzer to determine the branch with rupture in the network. The simulated result obtained shows that the system can monitor and detect a fault in the Feeder Fiber link, up to 20 km at optical power received of −44 dBm. The scheme is capable of detecting a fault in the various optical distribution network at the remote node in the customer’s end, at minimum optical power received of −58 dBm with negligible effects on data signal transmission.

A flexible upgrade path for the Australian National Broadband Network

This paper provides a flexible upgrade path for the Australian National Broadband Network (NBN), if the new government decides to alter the construction methodology to include a copper-based access system such as Fibre to the Node (FTTN). The approach described in this paper utilises fibre past premises to provide a transmission media for a Gigabit-capable Passive Optical Network (GPON). GPON to FTTN devices would be situated in pits adjacent to premises and utilise copper tails to provide a VDSL2 Internet connection to premises. The approach provides a flexible upgrade path for customers to move from their copper based access system to a Fibre to the Home (FTTH) system utilising the relatively future-proof GPON.

AN ENHANCED G-PON FAULT MONITORING TECHNIQUE USING OPTICAL SENSOR

In this study a technique for a centralized fault monitoring and detection in Gigabit-capable Passive Optical Network (G-PON) using fiber Bragg grating (FBG) sensor is proposed. The technique detects fault once it occurs at the vulnerable locations in the fiber optic distribution link by the proposed FBG devices. Monitoring signal in the C-band is reflected by a uniform FBG with different Bragg wavelengths and reflectivities. The FBGs serve as branch identifiers in the network. The reflected signal from the FBGs is analyzed at the Optical Line Terminal (OLT) in the Central Office (CO) by an Optical Spectrum Analyzer (OSA), to identify the branch with rupture in the network. The simulated result obtained shows that the system can monitor, and detect a fault in the physical layer of the optical distribution network with negligible effects on data signal transmission.

Experimental integration of quantum key distribution and gigabit-capable passive optical network

Quantum key distribution (QKD) ensures information-theoretic security for the distribution of random bits between two remote parties. To extend QKD applications to fiber-to-the-home optical communications, such as gigabit-capable passive optical networks (GPONs), an effective method is the use of wavelength-division multiplexing. However, the Raman scattering noise from intensive classical traffic and the huge loss introduced by the beam splitter in a GPON severely limits the performance of QKD. Here, we demonstrate the integration of QKD and a commercial GPON system with fiber lengths up to 14 km, in which the maximum splitting ratio of the beam splitter reaches 1:64. By placing the QKD transmitter on the optical line terminal side, we reduce the Raman noise collected at the QKD receiver. Using a bypass structure, the loss of the beam splitter is circumvented effectively. Our results pave the way to extending the applications of QKD to last-mile communications.

Bandwidth Resource Sharing on the XG-PON Transmission Convergence Layer in a Multi-operator Scenario

Passive optical networks (PONs) offer high network capacity and densified coverage at the cost of high capital expenditure. Therefore, it is desirable for network operators who deploy their own infrastructures to share their PON infrastructures to reduce the initial investment. The key problem of PON network sharing is how to balance the trade-off between isolation and utilization of bandwidth resources. In this paper,we introduce a bandwidth resourcesharing framework in XG-PONs (10 gigabit-capable PONs) amongmultiple operators. In this framework, each transmission convergence (TC) frame with fixed time slots (125 μs) is regarded as a bandwidth slice, which is the resource granularity for sharing. Then, we formulate the bandwidth resource-sharing problem and propose slice scheduling schemes to assign bandwidth slices to different operators. Our proposed schemes meet three key requirements of network sharing: isolation, customization, and efficient resource utilization. We study the efficacy of our schemes by employing an event-driven simulator. The results show our schemes could ensure resource isolation across operators andmaximize total resource utilization while providing the flexibility of running different customized algorithms to different operators.

Design and Implementation of a GPON-Based Virtual OpenFlow-Enabled SDN Switch

Passive optical networks (PON) have become a promising solution for accessing networks because of the advantages they offer, such as high efficiency, security, and cost reduction. However, network management in PON is not yet automated and needs network operator intervention. In recent years, software-defined networking (SDN) has become an emerging technology. Through the separation of control and data plane in SDN switches, SDN provides dynamically fine-grained traffic control that enhances total network controllability and manageability. In this paper, we leverage the benefits of gigabit-capable passive optical network (GPON), while enhancing its capabilities on traffic management to the same level as an SDN switch. More specifically, we abstract the underlying physical GPON into an OpenFlow-enabled virtual SDN switch. The virtual switch can be used to connect multiple sites in widespread geographic locations. Similar to a real OpenFlow switch, a GPON virtual switch can be controlled by a standard OpenFlow controller. In our design, an embedded OpenFlow agent resides in the optical line termination (OLT) of the underlying GPON. The agent communicates with the external OpenFlow controller and simultaneously uses optical network unit management and control interface inside the OLT to manage ONUs. We created a prototype system based on a commodity GPON network. In the virtual switch, we implemented all the OpenFlow functions, including packet forwarding, bandwidth metering, statistical data collection, and status reporting. The experimental results show that the GPON virtual switch can correctly perform all the functions defined in the OpenFlow 1.3 specification. Its performance on flow entry modification time, dynamic bandwidth control, and switch status monitoring are comparable to the performance of a real OpenFlow switch.

CHANNEL MONITORED CHANNEL DUPLEXER FOR OPTIMIZATION OF BIDIRECTIONAL PASSIVE OPTICAL NETWORK

Method of optimizing the optical network transmission in access network has been investigated in many years. Unidirectional optical transmission system is the earliest method of delivering the information. In recent years, bidirectional optical transmission system is the most popular network and shall be the first right of refusal to deploy nowadays. It is justify enough by the massive deployment of the popular state-of-the-art network named Passive Optical Network (PON) in Fiber To The Home (FTTH) technologies. Combining 3 wavelengths includes (1) 1310nm, (2) 1490nm, and (3) 1550nm within a fiber is the method used on Gigabit Capable Passive Optical Network (GPON) or Gigabit Ethernet Passive Optical Network (GEPON/EPON). Combining 2 different wavelengths for uplink and downlink on Small Form Pluggable (SFP) lasers also has been a method used to optimized and saved the fiber infrastructure. Compared those techniques, the research optimization focusing on introducing a passive optical duplexer that combined the same wavelength from both end with the element of monitoring via different wavelength to confirm the network availability. In the design, a unidirectional converter able to operate at a nominal 1310nm or 1550nm windows shall be demonstrated up to 10Gbps Ethernet signal.

Adaptive state transition control for energy-efficient gigabit-capable passive optical networks

In this paper, we investigate power management problems that affect gigabit-capable passive optical networks (GPONs). In GPONs, the basic principle for power reduction is to keep optical network units (ONUs) in the Power Saving state, wherein some of the hardware and software functions are turned off. Current research focuses on scheduling and determining the length of the sleep periods for ONUs that are in the Power Saving state. Our investigation indicates that keeping ONUs in the Power Saving state is not necessarily the most energy-efficient practice. The Power Saving state and the Full Power state must be jointly considered. Our study also reveals that traffic distribution is a critical factor. Considering only the average is insufficient. The variance of packet arrival also must be included when designing a green GPON. We have analyzed the power consumption in a GPON and determined the optimal load threshold for triggering a state transition from the Power Saving state to the Full Power state. For the reverse direction, we propose a neural network-based adaptive control scheme to achieve near optimal control of the transition from Full Power to Power Saving. We also propose a burst transmission scheme to determine the sleep period for an ONU in the Power Saving state. Unlike the proposal of ITU-T, which uses a fixed length for the sleep period, the state sojourn time in our approach is dynamically adjusted. We have carried out extensive simulations to evaluate the performance of the proposed scheme. Simulation results show that the total energy consumption of the proposed scheme is almost equal to the optimal control scheme.

Un estudio sobre distribución dinámica de longitudes de onda para redes gigabit ópticas pasivas

Este artículo presenta un estudio con el propósito de evaluar el impacto de la asignación dinámica de longitudes de onda en una red de acceso Gigabit óptica pasiva (GPON). En redes de acceso ópticas pasivas (PON), un terminal de línea óptico (OLT) alimenta diferentes PONs de tal forma que una longitud de onda se distribuye uniformemente entre las diferentes unidades de red óp­tica (ONU) en cada PON. Sin embargo, las redes PON no definen ningún tipo de comportamiento dinámico en la asignación de longitudes de onda en la red, a cambio, implementa una distribución de tipo completamente estático. En este artículo se evalúan las prestaciones de una red óptica de acceso en términos del caudal efectivo y tasa de paquetes perdidos en diferentes escenarios que de­scriben un número dado de ONUs, presentando un comportamiento fuera de perfil con un porcentage dado de tráfico en exceso para una distribución fija de una longitud de onda y para una asignación dinámica de varias longitudes de onda. Los resul­tados muestran que, en una operación multicanal con cuatro longitudes de onda, el caudal efectivo se incrementa un 19% sobre el ancho de banda neto para la configuración con una longitud de onda mientras que el porcentaje de paquetes per­didos se reduce un 20,2 % cuando se compara con el escenario de distribución estática.

Comprehensive Performance Assessment of Bipartition Upstream Bandwidth Assignment Schemes in GPON

With the emerging diversified services, the gigabit-capable passive optical network (GPON) has emerged as one of the most important technologies to support the next-generation broadband access networks. Dynamic bandwidth assignment (DBA) avoids transmission collision in the upstream direction and improves the efficiency of the PON upstream bandwidth by dynamically adjusting the bandwidth among the optical network units (ONUs) in response to the ONU burst traffic requirement. Instead of using GATE and REPORT control messages in Ethernet PON DBA, the buffer REPORT/GRANT message is embedded into a GPON encapsulation mode (GEM)/GPON transmission convergence (GTC) frame, and all ONUs are essentially polled simultaneously within a GEM/GTC frame in GPON DBA. This paper proposes a bipartition DBA (BI-DBA) mechanism in GPON that divides the transmission cycle time into two groups and adjusts the bandwidth dynamically. Two cases are considered: in the first case, there is a first group for high priorities T-CONT 1 and T-CONT 2 and a second group for low priorities T-CONT 3 and T-CONT 4, called class based scheduling (CBDBA). In the second case, the first and the second group are created according to the number of ONUs, called group based scheduling (GBDBA). Moreover, the T-CONT 2 traffic has a prediction mechanism and recycles the remaining unused bandwidth for the low-priority T-CONTs. The GBDBA has better system performances in terms of the average bandwidth utilization, packet latency, and drop probability; on the other hand, the CBDBA has better packet delay performance when the proportion of T-CONT 1 traffic is higher and has better fairness performance.

English

There is growing demand for higher bit rates in the access domain due to the emergence of bandwidth-hungry applications such as video-on-Demand and file sharing. Gigabit-capable passive optical network (GPON) is the most important PON. In a hybrid wave division multiplexing/time division multiplexing (WDM/TDM passive optical network (PON), Quadrature amplitude modulation (QAM) is proposed as a way to achieve the necessary high bit rates. In this paper, 2.5-Gb/s hybrid WDM/TDM downstream link is presented, using radio-over-fiber (RoF) techniques in the GPON network, where 16QAM is used at 2.4 GHz frequency. The result shows a good performance with a distance of 25 km for single mode fiber which serves up to 32 users. The analysis was made based on the performance of eye and constellation diagrams.   Key words: Hybrid wavelength division multiplexing / Time domain multiplexed -passive optical network (WDM/TDM-PON, radio-over-fiber (RoF), Quadrature amplitude modulation (QAM) modulation.

Integration of Mobile Backhaul and Broadband Fixed Access Networks in Urban Metropolitan Areas

Integration of mobile backhaul and broadband fixed access networks is a practical and inexpensive solution. This study discusses integration in urban metropolitan areas when a broadband fixed access network is based on gigabit-capable passive optical network and mobile backhaul is intended for the 3G global system for mobile communication networks. Bandwidth and quality of recovery clock are considered as two main parameters for successful integration. Two clock recovery approaches are described, and their performances are measured on the real gigabit-capable passive optical network system.

Demonstration of a WDM/TDM hybrid PON based on a colorless frame-level reach extender

We propose a hybrid passive optical network (PON) consisting of a 2.5Gb/s reflective semiconductor optical amplifier (RSOA)-based 32 channel loopback wavelength division multiplexing-passive optical network (WDM–PON) and a colorless OEO-based frame-level reach extender (RE). This hybrid PON is designed to support a 128-way split over a 50km transmission distance per single wavelength channel. We experimentally demonstrate the feasibility of this design through downstream and upstream packet transmission with a commercial gigabit-capable PON (GPON) product. Even if the colorless frame-level RE uses active devices at the remote node, it is still possible to increase the optical link budget through backward compatibility with existing GPON products. This design also provides wavelength conversion and an upstream burst-to-continuous mode conversion between the WDM–PON and GPON. The proposed hybrid PON can satisfy a packet loss ratio (PLR) of 10−10 at the downstream and upstream transmission including the use of forward error correction (FEC).

Gigabit-capable Passive Optical Network in Telecommunication Networks

The main application and usage of a gigabit-capable passive optical network in a telecommunication network is for providing triple-play services to resident users. However, the gigabit-capable passive optical network itself has more bandwidth than triple-play users need, as well as other mechanisms like the ability to provide quality of service. This excess bandwidth and these advance mechanisms can be utilized for other services and applications inside the same telecommunication network. Some of these advanced applications that use this excess bandwidth and capability of providing quality of service are described, and results of tests are presented in this article.