UDWDM-PON using low-cost coherent transceivers with limited tunability and heuristic DWA

A new Passive Optical Network (PON) for access, making use of Ultra Dense Wavelength Division Multiplexing (UDWDM) by densely spacing channels at few GHz, and introducing the “wavelength-to-the-user” concept, is proposed. The key challenge will be developing low-cost coherent transceivers, providing an excellent selectivity while avoiding filters, and furnishing high sensitivity, which will allow high splitting ratios, large number of users and long distance reach. The Optical Distribution Network (ODN) at the outside plant is based on splitters and kept compatible with legacy systems. Optical Network Unit (ONU) designs realized with coherent transceivers using one or two lasers are presented and the corresponding Optical Line Terminal (OLT) architectures are introduced. The ONUs at customer premises own lasers with limited thermal tunability and their wavelengths are randomly distributed in a band. By using heuristic Dynamic Wavelength Assignment (DWA) schemes and extending the original working band, the required optical band is obtained and optimized. In activation processes, ONU acceptances up to 99.9% are achieved. Furthermore, in operation scenario under indoors and also under outdoors environmental conditions, ONU blocking probabilities below 0.1% and ONU availability ratios (OARs) up to 99.9% are demonstrated. The PON is dimensioned according to the number of deployed users and system reach; moreover, power safety and also fiber nonlinearities constraints are evaluated, illustrating the characteristics of the projected network. Finally, the coexistence with legacy networks is discussed.Peer ReviewedPostprint (author's final draft

SARDANA: an all-optical access-metro WDM/TDM-PON

A new optical access network, named “Scalable Advanced Ring-based passive Dense Access Network Architecture” (SARDANA), is presented. It transparently integrates WDM metro and TDM PON access technologies, implementing ring protection, 100 km reach and up to 1024 users served at 10 Gb/s, with passive highly-shared infrastructure. The introduced innovations are hybrid ring/tree WDM/TDM Passive Optical Network (PON) architecture; a resilient remote node (RN), which is distantly pumped from the Optical Line Terminal (OLT); and a reflective ONU (Optical Network Unit); as well as an enhanced Medium Access Control (MAC) protocol.Postprint (published version

Agile reconfigurable and traffic adapted all-optical access-metro networks

The emerging high bandwidth and on-demand user applications require improvements in capacity, configurability and resiliency in next generation optical access networks to incrementally expand on the basis of customers requirements. New architectures and technologies are needed to achieve also scalability and active traffic adaptation. In this article an all-optical merger of access and metro networks is proposed with the use of Reconfigurable Optical Add Drop Multiplexers (ROADMs) and Optical Burst Switching Multiplexers (OBSMs), which are new network elements multiplexing at optical burst level. The resulting novel network architectures, named the OBSWAMA network, are evaluated as an innovative solution to reach a flexible, dynamic and efficient solution for the aforementioned next generation optical access networks.Peer ReviewedPostprint (published version

Flexible mobile fronthaul with coherent UDWDM-PON

Ultra Dense Wavelength Division Multiplexing (UDWDM) has been proposed for future Passive Optical Networks (PONs) to support the increase of access traffic, furnishing an improved capacity while introducing point-to-point logical connections with the Wavelength-To-The-User (WTTU) concept, enabled by low cost coherent transceivers with high sensitivity. Furthermore, considering wireless networks, a centralized processing in a Cloud-Radio Access Network (C-RAN) needs reconfigurable abilities to bring benefits to mobile systems with dynamic demands of huge bandwidth between Remote Radio Heads (RRHs) at base stations and Baseband Units (BBUs) at the central office. To achieve this goal in the access network, we propose a flexible architecture design of an UDWDM-PON, which adapts the available bandwidth to different users and classes of services and can reconfigure the connections between RRHs and BBUs. © 2018 IEEE.Peer ReviewedPostprint (published version

GPON scheduling disciplines under multi-service bursty traffic and long-reach approach

Gigabit-capable PON (GPON) is the optical access standard being deployed by many incumbent operators, but the Dynamic Bandwidth Allocation (DBA) algorithm for multi-service Quality of Service (QoS) is not specified; hence, to provide QoS we propose fair DBA scheduling disciplines adapted to bursty traffic. Moreover, Long- Reach (LR) access is a promising scheme for future next generation access networks, enabling for a large number of customers in the access/metro area. We improve our scheduling disciplines to enhance the transmission efficiency in the LR approach by using a traffic prediction.Peer ReviewedPostprint (published version

GPON redundancy eraser algorithm for long-reach extension

Long-Reach (LR) extension is a promising scheme for future next generation access networks, enabling less Central Offices (COs) in the field and a large number of customers in the access/metro area. Because of the large propagation time between ONUs and OLT, inefficiency occurs in the Dynamic Bandwidth Allocation (DBA) protocols. To solve this drawback the GPON Redundancy Eraser Algorithm for Long-Reach (GREAL) is proposed, removing the redundancy caused by scheduling intervals (SIs) smaller than the Round-Trip-Time (RTT), while providing also multi-service QoS. This algorithm is independent of the SIs and uses real data queuing information without prediction, achieving a great enhancement in bandwidth utilization.Peer ReviewedPostprint (published version

An improved dynamic wavelength assignment in statistical UDWDM-PONs

Dynamic wavelength assignment (DWA) is investigated for managing ultra-dense wavelength division multiplexing-passive optical networks (UDWDM-PONs). The optical network units (ONUs) own lasers under limited thermal tunability and their wavelengths have random distribution in a band. ONU and optical line terminal (OLT) architectures with coherent transceivers are proposed, providing a spectral efficiency suitable for a high capacity PON with large number of users and long-reach approach. In activation processes, ONU acceptances up to 99.99% are obtained with a DWA technique. Under standard environmental conditions, the DWA method is combined with guard bands and then ONU blocking probabilities below 0.1% and availability ratios up to 99.99% are achieved.Peer ReviewedPostprint (published version

Planning and designing FTTH networks: elements, tools and practical issues

Fiber-To-The Home (FTTH) provides the offered and new broadband services. Now it is deployed massively worldwide with Passive Optical Networks (PONs), being the EPON and GPON standards the most used. In this paper we consider solutions for planning and designing such optical fiber access networks from the point of view of an incumbent operator; taking into account components administration, mapping tools, design applications and automation resources; therefore, managing infrastructures, materials, geography, houses,buildings and users databases. The networks will be dynamic, so the proposed designs and utilities must also be active to reach thousands of passed homes and to cover the life-cycle of the networks and not only the initial built.Peer ReviewedPostprint (published version

Grade of service in UDWDM-PON with statistical wavelength subscribing

The Grade of Service (GoS) or ONU rejection probability in coherent UDWDM-PONs with ONU lasers under limited tunability is evaluated. Each active ONU is assigned an exclusive wavelength channel, which is managed by heuristic Wavelength Assignment (WA) schemes. With a take rate of 90%, GoS values below 0.1% are achieved, but when statistical subscribing is considered, the GoS is dramatically improved.Peer ReviewedPostprint (published version

Characterising the rate dependent response of adhesively bonded structures

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