Ethernet Passive Optical Network Architecture Research Articles

Power Budget Analysis of a Distributed 5G EPON Network

This work studies the power-budget analysis of a fully distributed ring-based EPON(Ethernet Passive Optical Network) architecture that enables the support of a converged PON-5G access networking transport infrastructure that is capable to seamlessly backhaul both mobile and wireline multimedia traffic and services.

Mitigating the IPTV Zap Time in Enhanced EPON Systems

Zap time (channel switching time) is a critical quality of experience (QoE) metric for IPTV systems where synchronization, signaling, and propagation delays are the components under consideration. An Ethernet passive optical network (EPON) is one of the main infrastructures in broadband access networks that provides high bandwidth with low propagation delay. The functionality of the EPON hardware architecture can be extended by adding programmable networking engine (PNE) and programmable sub-system (PSS) components in the optical line terminal (OLT) and optical network unit (ONU) as described in this paper to improve IPTV delivery performance for synchronization and signaling delays in terms of traffic localization. Furthermore, a new IPTV delivery mechanism is proposed to eliminate synchronization delay by buffering the current I-frames of broadcasted channels in the OLT for possible new coming requests and dropping additional streams along with the main stream. The OLTand ONUs implement a multicasting mechanism to handle part of the IPTV request as intra-domain traffic. Simulation results show that the proposed mechanism significantly improves the QoE and quality of service (QoS). IPTV bandwidth usage and system throughput have improved mean packet delays and packet loss in enhanced EPON architecture.

A Ring-Based Wireless Optical Network to Reduce the Handover Latency

This paper proposes a ring-based integrated wireless optical network architecture and an associated protocol that involves Ethernet passive optical network (EPON) and long term evolution (LTE) wireless network. The architecture along with the proposed protocol is instrumental toward the reduction of handover delay. The proposed ring-based EPON architecture facilitates the implementation of the X2 interface for LTE network by enabling the optical network units of the EPON backhaul to directly communicate with each other. The work further discusses about an open access network architecture where a single EPON can be used by multiple mobile service providers without compromising information security. Extensive simulations have been carried out to evaluate the performance of the proposed network. An analytical model has been introduced to calculate the queuing delay experienced by the X2 interface. The model has been validated with the simulations results.

QoS-aware energy-efficient mechanism for sleeping mode ONUs in enhanced EPON

Ethernet passive optical network (EPON) is a broadband access time-division multiplexing passive optical network technology which can be referred to as green network, as it has less power consumption compared with other networks. The optical network unit (ONU) is the best candidate to implement energy-saving adjustments in EPON. Turning off the ONU transmitter (Tx)/receiver (Rx) for substantial time is a common method to achieve the energy saving. However, setting overlong sleep duration decreases the QoS, while short sleep duration increases the ONU power consumption. The challenging issue is how to balance the trade-off between achieving energy saving and guaranteeing QoS. In this paper, we introduce an enhanced EPON architecture and a QoS-aware energy-saving mechanism to reduce ONU energy consumption and guarantee an overall QoS metric based on the ITU-T standards requirements. To achieve the energy saving in the upstream/downstream direction, two sleep durations are defined for the ONU's Tx/Rx to generate four ONU modes including active, transmission, doze, and sleep. Simulation results show that the proposed scheme improves the energy efficiency 44 % in average to fulfill the QoS metrics in terms of packet loss, delay and jitter, and the buffer requirement.

A Hybrid Scalable Peer-to-Peer IP-Based Multimedia Services Architecture in Ethernet Passive Optical Networks

Peer-to-peer (P2P) applications such as P2P video streaming and internet video calling have gained tremendous popularity and are expected to be vastly increasing in the next few years. However, low-cost large-scale video services have remained an intangible goal. The ethernet passive optical network (EPON) is being regarded as one of the promising for next-generation optical access solutions in the access networks attempt to tackle this problem but facing a major challenge to offer scalable large-scale video services. Therefore, in this paper, we propose an architecture which combines the advantages of EPON and P2P architecture to provide scalable Internet Protocol delivery multimedia services and improve quality-of-services. In the proposed architecture, we design new optical network unit (ONU) mechanisms, which support traffic redirection communication among ONUs in combination with caching. Thus, it can reduce the resource consumption and add extra downstream bandwidth at the optical line terminal since the intra-PON traffic is not necessary to be buffered and scheduled in the downstream direction. Finally, we propose a “Redirect” dynamic bandwidth allocation scheme, which can support intra-PON traffic redirection and intertraffic bandwidth allocation. Simulation results have shown that our proposed architecture can improve the overall QoS in terms of end-to-end delay, jitter, system throughput, fairness, and packet dropping rate.

Experimental demonstration of an improved EPON architecture using OFDMA for bandwidth scalable LAN emulation

We propose and demonstrate an improved Ethernet passive optical network (EPON) architecture supporting bandwidth-scalable physical layer local area network (LAN) emulation. Due to the use of orthogonal frequency division multiple access (OFDMA) technology for the LAN traffic transmission, there is no need to change the existing EPON architecture. Only one receiver at each optical network unit (ONU) is required to detect both LAN traffic and EPON downstream traffic, which makes the proposed system simple and cost-effective. Moreover, flexible assignment of LAN traffic bandwidth is realized by allocating different number of subcarriers or using different modulation formats. The 250 Mb/s 4-quadrature amplitude modulation (4-QAM) and 500 Mb/s 16-QAM OFDM LAN traffic are successfully emulated with the EPON traffic in our experiment.

A Novel Dynamic Bandwidth Allocation Mechanism for Star-Ring-Based EPON

Ethernet Passive Optical Network (EPON) is proposed as a simple, cost-effective and scalable solution for bandwidth bottlenecks in access networks which can enhance the system performance because it transmits the aggregated high-speed traffic from hundreds of subscribers. Dynamic Bandwidth Allocation (DBA) mechanism has not yet been seriously considered for use in star-ring EPON architecture. In this paper, a distributed QoS-based dynamic bandwidth allocation (DQ-DBA) scheduling mechanism for the star-ring-based EPON architecture including optical line terminal (OLT), Sub-OLT and ONUs has been proposed to improve the system performance of traditional tree-based EPON architecture. In DQ-DBA, the highest-priority traffic of each ONU is directed to the OLT by the tree structure; moreover, the lower-priority traffic on each ONU is transmitted to the Sub-OLT by ring architecture. This approach can effectively resolve the idle period problem and reduce the overloading of OLT in conventional DBA mechanisms. Exhaustive simulation experiments are performed to compare the system performance between the tree and the star-ring architectures and validate the effectiveness of the proposed mechanism. Simulation results show that the proposed DQ-DBA mechanism in star-ring architecture can reduce packet delay and jitter for the high-priority traffic, thus ensuring the quality of service (QoS) regardless of subscriber numbers.

Tunable self-seeding Fabry–Pérot laser diode for upstream multiwavelength shared ethernet passive optical network

We present a novel upstream multiwavelength shared ethernet passive optical network architecture, based on a proposed self-seeding Fabry-Perot laser diode (FP-LD) at the optical network unit. The performances of the wavelength and power stability, side-mode suppression ratio, and tuning range for the proposed tunable self-seeding laser module are experimentally investigated. The bit-error-rate measurement is performed with direct modulation on FP-LD of 1.25 Gbps upstream data. The performance benefits from the upstream wavelengths sharing are showed via simulations.

Novel wavelength and bandwidth allocation algorithms for WDM EPON with QoS support

Ethernet passive optical networks (EPONs) have been considered as the one of the most promising candidates for next-generation access networks. However, the EPON architecture although cost effective is bandwidth limited and quality of service (QoS) support is still a major concern. In this paper, we propose a cost-efficient wavelength division multiplexing (WDM) EPON architecture. We present two wavelength and bandwidth allocation algorithms with full QoS support to fulfill all requirements of new application and services in a converged triple play network. We analyze and compare the presented models and algorithms in terms of delay, jitter, queue occupancy, throughput and overall system performance. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.

Design and Analysis of a WDM EPON for Supporting Private Networking and Differentiated Services

Although EPONs have been proposed as a means of overcoming the bandwidth bottleneck problem in local access networks, they may not be able to meet the ever-growing bandwidth demand from users in the near future. Accordingly, this study presents what we believe to be a novel wavelength-division-multiplexing (WDM) Ethernet passive optical network (EPON) system based on an arrayed-waveguide-grating (AWG) module to meet the rapidly increasing bandwidth demand anticipated in the future. The use of the AWG enables the proposed WDM EPON architecture to achieve wavelength spatial reuse and to provide an intercommunication capability between optical network units (ONUs). As a result, the architecture not only allows upstream access to the central office, but also facilitates a truly shared LAN capability among the end users. Furthermore, the proposed WDM EPON scheme takes account of the requirement for backward compatibility with the IEEE 802.3ah multipoint control protocol and incorporates a dynamic bandwidth allocation scheme and a quality-of-service provisioning mechanism to arbitrate the access of the individual ONUs over the WDM layer. An analytical framework is developed for evaluating the mean packet delay and mean queue length of the proposed WDM EPON system. The analytical results derived using this framework are found to be in good agreement with those obtained from computer simulations.

Experimental demonstration of a distributed ring-based EPON architecture

We experimentally demonstrate error free performance of a simple ring-based Ethernet Passive Optical Network (EPON) architecture that supports truly shared LAN capability among users as well as a fully distributed dynamic bandwidth allocation DBA scheme. The proposed distributed architecture can also be utilized as a packet-based mobile backhaul transport network to backhaul emerging mobile services across the PON-based fiber infrastructure. Utilizing PON access infrastructure as a mobile backhaul enables a seamless migration path to fixed-mobile convergence solutions.

Protection for an Immediate Split Structure of Tree-Based EPON Architecture-Ideal Condition Analysis

Problem statement: Ethernet Passive Optical Network (EPON) was proposed to overcome the bandwidth bottleneck at the Access Networks due to its simplicity, cost effective and wide spread deployment. A failure in access networks can cause serious problems, because access network transmit aggregated high speed traffic from hundreds of subscribers. Protection and restoration mechanisms have been applied in backbone networks, but access networks are not considered significantly in the scope of survivability. Approach: In this study, we proposed a cost effective protection scheme for a novel tree-based EPON architecture. Immediate Split Structure (ISS) means the signal was totally split after pass through the first optical splitter. This was the second proposal method after first suggestion using Optical Cross Add and Drop Multiplexer (OXADM) as a restoration switch. In this study we used only 2 × 2 and 2 × 1 optical switches combination to divert the traffic to the alternative path. Three faulty conditions were considered in this research and OptiSystem, Inc software was used to prove the solution feasibility. Results: The Bit Error Rate (BER) performances were measured by a 1.25 Gb sec-1 Non-Return-to-Zero (NRZ) pseudo random binary sequence (PRBS) with a pattern length of 231-1 for the downstream traffic between the OLT and 8 ONUs. Our results were obtained by observing bit error rates, eye diagrams and optical power levels in ideal condition. Conclusion: The survivability of EPON is necessary to provide seamless services and ensure network reliability. Single failure in the line connected will activate dedicated protection while shared protection was activated when both fiber (working and standby fiber) are breakdown. We analyzed the system in ideal condition to prove the system feasibility.

Survivable broadband local access PON architecture: a new direction for supporting simple and efficient resilience capabilities

This work proposes a two-fiber self-healing ring-based local access passive optical network (PON) architecture that addresses some of the limitations of current tree-based PON architectures including supporting private networking capability as well as providing simple and cost-effective fully distributed resilience capabilities against most kinds of networking failures. Specifically, this work proposes and devises a simple self-healing Ethernet PON architecture that supports a truly shared LAN capability among end users. The main characteristic of the proposed architecture is that it supports a fully distributed control plane among the optical network units (ONUs) for ONU-to-ONU communication. The control plane supports fully distributed fault detection and recovery mechanisms as well as a decentralized dynamic bandwidth allocation scheme in which the optical line terminator is excluded from both the bandwidth arbitration and fault detection and recovery processes. The proposed decentralized automatic protection switching technique is capable of protecting against both node (ONU) and fiber failures (distribution and trunk) through active participation of ONUs. This scheme enables the recovery of all network traffic including upstream, downstream, and LAN data. In addition, the proposed protection technique can protect against any combination of concurrent double failures including trunk and distribution fiber breaks and node failures.

Dynamic Bandwidth Allocation for Supporting Dynamic Service Level Agreements in EPON

Recently, Ethernet Passive optical networks (EPON) is being deployed widely as the next generation broadband access networks due to the convergence of low cost Ethernet equipment and low cost fiber infrastructure. Because of the use of shared transmission media between all users, an efficient dynamic bandwidth allocation (DBA) is necessary to enable the quality of service (QoS) in EPON. However, to receive guaranteed QoS, end users first have to sign the contract called Service Level Agreement (SLA) with service provider in which specifies the QoS performances of the provider has to promise as well as the obligations the end users have to obey. Therefore, the central issue of QoS support in EPON is the appropriate dynamic bandwidth allocation scheme that makes sure the SLAs can be exactly fulfilled. According to the negotiation fashions, the SLA can be static or dynamic. Based on current standardized EPON architecture, most studies of the DBA schemes have only focused on achieving static SLAs, and the DBA for dynamic SLAs is rarely discussed. This paper firstly addresses this issue with an extension of EPON framework that supports dynamic SLAs negotiation, and further proposes a dynamic bandwidth allocation (DBA) scheme to fulfill the dynamic SLAs. Detailed simulation experiments are also conducted to study the performance and validate the effectiveness of the proposed solution.

QoS control schemes for two-stage Ethernet passive optical access networks

Ethernet passive optical networks (EPONs) have emerged as the one of the most promising candidates for next-generation access networks. These new architectures couple low-cost optics with advanced edge electronics to offer vastly improved scalability over competing digital subscriber line and cable modem offerings. This paper proposes several novel architectural enhancements for EPON, which will help increase the viability of optical access over a broader range of subscriber access scenarios. Specifically, this paper proposes a two-stage EPON architecture that allows more end-users to share an optical line terminal link, and enables longer access reach/distances (beyond the usual 25 km distance). In addition, a new dynamic bandwidth allocation (DBA) algorithm is proposed to effectively allocate bandwidths between end users. This DBA algorithm can support differentiated services in a network with heterogeneous traffic. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed architecture and algorithms.

A Novel Decentralized Ethernet-Based PON Access Architecture for Provisioning Differentiated QoS

To date, the mainstream ethernet passive optical network (EPON) bandwidth allocation schemes as well as the new IEEE 802.3ah Ethernet in the first mile Task Force specifications have been centralized, relying on a component in the central office [optical line termination (OLT)] to provision upstream traffic. Hence, the OLT is the only device that can arbitrate time-division access to the shared channel. Since the OLT has global knowledge of the state of the entire network, this is a centralized control plane in which the OLT has centralized intelligence. This paper proposes novel distributed EPON architectures, and in the process proves that these distributed networking architectures and the associated bandwidth allocation algorithms and protocols have characteristics that make them far better suited for provisioning quality of service (QoS) schemes necessary for properly handling data, voice, video, and other real-time streaming advanced multimedia services over a single line. Specifically, this paper proposes a novel ethernet over star coupler-based PON architecture that uses a fully distributed time-division multiple-access (TDMA) arbitration scheme. Supported by the decentralized scheme, this paper proposes several QoS-based dynamic bandwidth allocation (DBA) algorithms in which the OLT is excluded from the implementation of the time slot assignment. In contrast with the mainstream centralized EPON architectures that combine priority queuing [intra-optical network unit (ONU) scheduling] with DBA schemes (inter-ONU scheduling), the proposed distributed EPON architecture supports differentiated services through the integration of both scheduling mechanisms at the ONU (intra-ONU scheduling). The introduction of this integration feature that can only be supported by a decentralized architecture provides better QoS guarantees. Furthermore, in addition to the added flexibility and reliability, the overall performance of the proposed decentralized EPON architecture and the associated bandwidth allocation algorithms are shown to be at least as efficient as their centralized counterparts.