On Greening Optical Access Networks

On Greening Optical Access Networks
Author: Mina Taheri Hosseinabadi
Publisher:
Total Pages: 79
Release: 2016
Genre:
ISBN:

With the remarkable growth of fiber-based services, the number of FTTx subscribers has been dramatically increasing in recent years. Owing to the environmental concern, reducing energy consumption of optical access networks has become an important issue for network designers. In Ethernet passive optical network (EPON), the optical line terminal (OLT) located at the central office broadcasts the downstream traffic to all optical network units (ONUs), each of which checks all arrival downstream packets to obtain those destined to itself. Since traffic of ONUs changes dynamically, properly defining the sleep mode for idle ONUs can potentially save a significant amount of energy. However, it is challenging to shut down an ONU receiver as the ONU needs to receive some downstream control packets to perform upstream transmission. In this framework, a novel sleep control scheme is proposed to address the downstream issue which can efficiently put ONU receivers to sleep. This dissertation further defines multiple levels of power saving in which the ONU disables certain functions based on the upstream and downstream traffic load. The proposed schemes are completely compatible with the multi-point control protocol (MPCP) and EPON standards. Elimination of the handshake process makes the sleep control schemes more efficient. Currently, OLTs also consume a significant amount of energy in EPON. Therefore, reducing energy consumption of OLT is as important as reducing energy consumption of ONUs; such requirement becomes even more urgent as OLT keeps increasing its provisioning data rate, and higher data rate provisioning usually implies higher energy consumption. Thus, a novel energy-efficient OLT structure, which guarantees services of end users with a smallest number of power-on OLT line cards, is proposed. More specifically, the number of power-on OLT line cards is adapted to the real-time incoming traffic. Also, to avoid service disruption resulted by powering off OLT line cards, a proper optical switch is equipped in OLT to dynamically configure the communications between OLT line cards and ONUs. By deploying a semi-Markov based technique, the performance characteristics of the sleep control scheme such as delay and energy-saving are theoretically analyzed. It is shown that, with proper settings of sleep control parameters, the proposed scheme can save a significant amount of energy in EPON.

Energy-efficient Optical Access/in-building Networks

Energy-efficient Optical Access/in-building Networks
Author: Tolga Ayhan
Publisher:
Total Pages:
Release: 2015
Genre:
ISBN:

This dissertation focuses on the design of energy-efficient optical access/in-building networks and their protocols. We introduce the Cascaded Bit-interleaved optical network protocol, an energy-efficient solution aiming to achieve low power consumption in converged optical access/in-building networks while providing high data rates to end-users, and propose a novel network architecture for optical access/in-building networks. In the proposed network architecture, optical-electrical-optical (OEO) regeneration is employed at the interface between access and in-building networks. The downstream frames are generated in the central office using a two-stage bit-interleaving scheme. In the downstream direction, the network nodes only process the data destined for them at a lower clock rate than that of the aggregate passive optical network (PON). In the upstream direction, no word alignment or decoding is performed in the intermediate nodes. We present detailed simulation and experimental results we obtained and show that a significant reduction in the power consumption of access/in-building networks can be achieved when the proposed Cascaded Bit-interleaved Protocol is employed in conjunction with the proposed network architecture.

Coherent Optics for Access Networks

Coherent Optics for Access Networks
Author: Zhensheng Jia
Publisher: CRC Press
Total Pages: 128
Release: 2019-10-28
Genre: Technology & Engineering
ISBN: 1000736962

This book will highlight the motivation for coherent optics in access and introduce digital coherent optical system in detail, including advanced modulation formats, architecture of modulation and detection, and DSP flow for both transmitter and receiver. This book will also demonstrate potential approaches to re-design and re-engineer the digital coherent concept from long-haul and metro solutions to the access network, leveraging reduction in complexity and cost as well as the benefits of capacity increases and operational improvements. This book will illustrate the details on optimization of the digital, optical, and electrical complexity and standardization and interoperability.

Contributions Towards Softwarization and Energy Saving in Passive Optical Networks

Contributions Towards Softwarization and Energy Saving in Passive Optical Networks
Author: Hamzeh Khalili
Publisher:
Total Pages: 153
Release: 2018
Genre:
ISBN:

Ths thesis is a result of contributions to optimize and improve the network management systme and power consumption in Passive Optical Network (PON). Passive Optical Network elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks by decoupling control plane from data plane. Currently, network management in PON networks is not always automated nor normalized. One goal of the researchers in optical networking is to improve the programmability, efficiency, and global optimization of network operations, in order to minimize both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) by reducing the complexity of devices and its operation. Therefore, it makes sense to use an SDN approach in order to manage the passive optical network functionalities and migrating must of the upper layer functions to the SDN controller. Many approaches have already addressed the topic of applying the SDN architecture in PON networks. However; the focus was usually on facilitating the deployment of SDN-based service and so Service Interoperability remains unexplored in detail. The main challenge toward this goal is how to make compatible the synchronous nature of the EPON media access control protocols with the asynchronous architecture of SDN, and in particular, OpenFlow. In our proposed architecture, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in term of delay and throughput when compared to legacy PONs. Nowadays, many researchers are working simultaneously to develop power saving techniques and improves energy efficiency in the PON network, and since the contribution of access networks to the global energy consumption is large, energy efficiency has become an increasingly important requirement in designing access networks. Therefore, energy-saving approaches are being investigated to provide high performance and consume less energy. Several techniques have been proposed to increase energy efficiency in PON networks. Such techniques are related to the centeralized DBA but the advantage of power saving in a distributed DBA remains untouched. We present a distributed energy-efficient Dynamic Bandwidth Allocation (DBA) algorithm for both the upstream and downstream channels of EPON to improve energy efficiency in EPON networks. The proposed algorithm analyzes the queue status of the ONUs and OLT in order to power-off the transmitter and/or receiver of an ONU whenever there is no upstream or downstream traffic. We have been able to combine the advantage of a distributed DBA such as 01SPON (a smaller packet delay, due to the shorter time needed by 01SPON to allocate the transmission slots) and the energy-saving features (that come at a price of longer packet delays due to the fact that switching off the transmitters make the packet queues grow). Our proposed DBA algorithm minimizes the ONU energy consumption across a wide range of network loads, while maintaining at an acceptable level the penalty introduced in terms of channel utilization and packet delay.

Opportunities and Challenges of Industrial IoT in 5G and 6G Networks

Opportunities and Challenges of Industrial IoT in 5G and 6G Networks
Author: Yu, Poshan
Publisher: IGI Global
Total Pages: 321
Release: 2023-06-07
Genre: Computers
ISBN: 1799892689

Modern communication technologies such as 5G and 6G and the industrial internet of things have important attributes to meet the requirements of industries, and with the rapid development of the fourth industrial revolution and beyond, it is unavoidable that these will fulfill the necessary requirements of this important part of modernization. Opportunities and Challenges of Industrial IoT in 5G and 6G Networks ranges from the application of recently ratified communication standards, theoretical knowledge that provides tangible insight for understanding the principles of operation, design, implementation, and planning, to the outcomes from deployment of industrial projects. Covering topics such as 5G network programmability, industry policies, and optical networking technologies, this premier reference source is a valuable resource for computer scientists, IT specialists, industry consultants and professionals, business leaders, libraries, students, researchers, and academicians.