Ahmad R. Dhaini

Dynamic Wavelength and Bandwidth Allocation in Hybrid TDM/WDM EPON Networks

We discuss a wavelength-division-multiplexed-based passive-optical-network (PON) architecture that allows for incremental upgrade from single-channel time-division multiple-access PONs in order to provide higher bandwidth in the access network. Various dynamic-wavelength and bandwidth-allocation algorithms (DWBAs) for wave-division multiplexed PON are presented; they exploit both interchannel and intrachannel statistical multiplexing in order to achieve better performance, especially when the load on various channels is not symmetric. Three variants of the DWBA are presented, and their performance is compared. While the first variant incurs larger idle times (and, hence, poor performance), the other two algorithms achieve better but different performance with critical dissimilarities. Our analysis also focuses on the fair assignment of excessive bandwidth in the upstream direction to highly loaded optical network units. We compare the performance of DWBA to another algorithm that relies on static-channel allocation. Furthermore, a study is presented wherein the number of wavelengths increases, and a comparison with interleaved polling with adaptive cycle time is shown. We use extensive simulations throughout this paper

Toward green next-generation passive optical networks

Energy saving in telecom networks in general and in optical IP networks in particular has been a growing field of research. Next-generation passive optical network, which is considered one of the most promising optical access networks, has notably matured in the past few years and is envisioned to massively evolve in the near future. This trend will increase the power requirements of NG-PON and make it no longer coveted. This article first provides a comprehensive survey of the previously reported studies on tackling this problem. A novel solution framework is then introduced, which aims to explore the maximum design dimensions and achieve the best possible power saving while maintaining the QoS requirements for each type of service. Results demonstrate the merits of the proposed framework.

Energy efficiency in TDMA-based next-generation passive optical access networks

Next-generation passive optical network (PON) has been considered in the past few years as a cost-effective broadband access technology. With the ever-increasing power saving concern, energy efficiency has been an important issue in its operations. In this paper, we propose a novel sleep-time sizing and scheduling framework for the implementation of green bandwidth allocation (GBA) in TDMA-PONs. The proposed framework leverages the batch-mode transmission feature of GBA to minimize the overhead due to frequent ONU on-off transitions. The optimal sleeping time sequence of each ONU is determined in every cycle without violating the maximum delay requirement. With multiple ONUs possibly accessing the shared media simultaneously, a collision may occur. To address this problem, we propose a new sleep-time sizing mechanism, namely Sort-And-Shift (SAS), in which the ONUs are sorted according to their expected transmission start times, and their sleep times are shifted to resolve any possible collision while ensuring maximum energy saving. Results show the effectiveness of the proposed framework and highlight the merits of our solutions .

Per-Stream QoS and Admission Control in Ethernet Passive Optical Networks (EPONs)

Ethernet passive optical networks (EPONs) are designed to deliver services for numerous applications such as voice over Internet protocol, standard and high-definition video, video conferencing (interactive video), and data traffic. Various dynamic bandwidth allocation and intra-optical network unit (ONU) scheduling algorithms have been proposed to enable EPONs to deliver differentiated services for traffic with different quality of service (QoS) requirements. However, none of these protocols and schedulers can guarantee bandwidth for each class of service nor can they protect the QoS level required by admitted real-time traffic streams. In this paper, we propose the first framework for per-stream QoS protection in EPONs using a two-stage admission control (AC) system. The first stage enables the ONU to perform flow admission locally according to the bandwidth availability, and the second stage allows for global AC at the optical line terminal. Appropriate bandwidth allocation algorithms are presented as well. An event-driven simulation model is implemented to study the effectiveness of the proposed schemes in providing and protecting QoS.

QoS Control for Guaranteed Service Bundles Over Fiber-Wireless (FiWi) Broadband Access Networks

The integration of ethernet passive optical networks (EPONs) and IEEE 802.16 has been lately presented as a promising candidate for next-generation broadband access. This paper investigates the performance of the integrated carrier when specific service bundles (SBs) with bandwidth guarantee and diverse quality of service requirements are provisioned. We first present a novel framework that fairly distributes the upstream network capacity among the different SBs. We then propose a novel delay-based admission control scheme to increase the network utilization and enable an inter-SB statistical multiplexing. To obtain the expected delay of each SB stream, a generic analytical model is developed. Based on this model, we further formulate some important performance measures such as queuing delay, end-to-end (from wireless user to the central office of PON) delay, average queue size and optimal orthogonal frequency division multiplexing frame length. Numerical results validate our analysis and highlight the advantages of the proposed solution.

Quality of Service in TDM/WDM Ethernet Passive Optical Networks (EPONs)

Ethernet Passive Optical Network (EPONs) are currently being designed to deliver multiple services and applications, such as voice communications (VoIP), standard and highdefinition video (STV and HDTV), video conferencing (interactive video) and data traffic access network. The emergence of new bandwidth intensive applications and the continuous demand for more bandwidth in a bandwidth limited EPON require an upgrade from current TDM to WDM-based PON which is currently of huge interest in both the academia and industry. In this paper we propose three new Dynamic Bandwidth Allocation (DBAs) schemes for QoS support in WDM-based PON networks. These schemes can comply with any ONU architecture (tunable lasers or multiple fixed transceivers). However, they vary in their performances (i.e. different jitter, delay, bandwidth utilization etc.). We study the performance of these DBAs using extensive simulation experiments.

Adaptive Fairness through intra-ONU Scheduling for Ethernet Passive Optical Networks

Ethernet passive optical networks (EPONs) are being designed to deliver multiple services and applications, such as voice communications (VoIP), standard and high-definition video (STV and HDTV), video conferencing (interactive video) and data traffic access network. However, most of the current work focuses on inter-ONU dynamic bandwidth allocation (DBA) algorithms. In this paper, we concentrate on the intra-ONU bandwidth allocation for different classes of services. We present a new intra-ONU scheduling scheme based on the Deficient Weighted Round Robin (DWRR) scheduling to achieve adaptive fairness among different classes of services. We validate our reasoning by measuring both the end-to-end delay of different traffic along with the jitter performance of high priority traffic using extensive simulation experiments.

Dynamic bandwidth allocation schemes in hybrid TDM/WDM passive optical networks

Ethernet Passive Optical Networks (EPONs) are considered the most promising solutions for upgrading the cur- rent congested access networks to enable the delivery of broad- band integrated services. Although current EPON architectures are economically feasible, they are however bandwidth limited. In this paper, we discuss a simple upgrade architecture from EPON to WDM-PON. We present various Dynamic Wavelength and Bandwidth Allocation algorithms (DWBAs) that exploit both inter-channel and intra-channel statistical multiplexing in order to achieve good performance. We use extensive simulation experiments to validate our reasoning. I. INTRODUCTION

Resource Management in STARGATE-Based Ethernet Passive Optical Networks (SG-EPONs)

At present there is a strong worldwide push toward bringing fiber closer to individual homes and businesses. Another evolutionary step is the cost-effective all-optical integration of fiber-based access and metro networks. STARGATE (IEEE Commun. Mag., vol. 45, no. 5, pp. 50-56, May 2007) is an all-optical access-metro architecture that does not rely on costly active devices, e.g., optical cross connects or fixed wavelength converters, and allows low-cost passive optical network (PON) technologies to follow low-cost Ethernet technologies from Ethernet PON (EPON) access into metro networks, resulting in significantly reduced cost and complexity. It uses an overlay island of transparency with optical bypassing capabilities. We first propose optical network unit architectures and discuss several technical challenges, which allow STARGATE EPONs (SG-EPONs) to evolve in a pay-as-you-grow manner while providing backward compatibility with legacy infrastructure and protecting previous investment. Second, and considering all the hardware constraints, we present the corresponding dynamic bandwidth allocation algorithm for effective resource management in these networks and investigate their performances (delay, throughput) through simulation experiments.

MC-FiWiBAN: an emergency-aware mission-critical fiber-wireless broadband access network

The convergence of optical and wireless networks has been envisioned recently as an attractive economic broadband access solution; yet, its usage has been restricted to public users only. To serve mission-critical services in public safety and disaster relief communications using the fiber-wireless integration, key challenges such as fault recovery, security, and quality of service assurance must be addressed. This article introduces MC-FiWiBAN, a new emergency-aware architecture that leverages layer 2 virtual private networks to support mission-critical services over the integration. Each virtual private network corresponds to a specific mission-critical system requirements bundle that is stipulated in the service level agreement and fulfilled via an effective resource management paradigm. Simulation results show that MC-FiWiBAN can commit guaranteed quality of service for emergency and non-emergency services.