A new all-optical access-metro network interface based on optical burst switching (OBS) is propos... more A new all-optical access-metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access-metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access-metro interface and architectures. Index Terms-Dynamic bandwidth allocation (DBA), metropolitan area network (MAN), optical burst switching (OBS), passive optical networks (PONs), quality of service (QoS).
2020 22nd International Conference on Transparent Optical Networks (ICTON), 2020
A coherent WDM-PON achieving ultra-dense spectral allocation is reported. The ONU at user premise... more A coherent WDM-PON achieving ultra-dense spectral allocation is reported. The ONU at user premises is built of coherent transceivers with two paired low-cost DFB lasers, one as local oscillator and the other as transmitter, offering simplicity and economy hardware. The ONU DFB lasers are paired to realize a simple blind activation process, having wavelengths with limited thermal tunability controlled by thermo-electric coolers (TECs). A MAC at the OLT at central office manages the spectrum channel assignment: the OLT furnishes an optical carrier wavelength for the new active ONU to obtain reception in a Dynamic Wavelength Allocation (DWA) by a smart control algorithm, thus assigning a down-channel; subsequently, another paired up-channel is also allocated to the ONU laser transmitter. The MAC can reassign the channels because of interference, collision or any network needs. The channelization of the optical bandwidth is flexible, thus adapting to different user bandwidths, serving all sorts of bit rates and suited for 5G technologies. Measures in an activation process and in channel reassignment have been performed in environment conditions, demonstrating the system feasibility.
2018 European Conference on Networks and Communications (EuCNC), 2018
The Grade of Service (GoS) or ONU rejection probability in coherent UDWDM-PONs with ONU lasers un... more 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.
2018 20th International Conference on Transparent Optical Networks (ICTON), 2018
Ultra Dense Wavelength Division Multiplexing (UDWDM) has been proposed for future Passive Optical... more 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.
2014 16th International Telecommunications Network Strategy and Planning Symposium (Networks), 2014
ABSTRACT We present a novel ONU architecture for coherent UDWDM-PON with randomly distributed ONU... more ABSTRACT We present a novel ONU architecture for coherent UDWDM-PON with randomly distributed ONU wavelengths. The ONU is built with one or two lasers exhibiting simple limited thermal tunability in a specific optical band, where the wavelengths are managed in a Statistical UDWDM approach. If only one laser is present at the ONU, it serves as both local oscillator for coherent receiver and transmitter in a Half-Duplex transmission mode. When two lasers are equipped, they can work in Full-Duplex transmission mode as receiver or transmitter indistinctly and back-up protection is provided in case of laser fail. Finally, a simple activation process based on Half-Duplex transmission for both lasers and a wavelength monitoring during operation is also proposed.
2017 19th International Conference on Transparent Optical Networks (ICTON), 2017
Ultra-Dense Wavelength Division Multiplexing (UDWDM) is a candidate for future Passive Optical Ne... more Ultra-Dense Wavelength Division Multiplexing (UDWDM) is a candidate for future Passive Optical Networks (PONs) to sustain the increase of access traffic, providing enhanced capacity with point-to-point logical connections while introducing the Wavelength-To-The-User (WTTU) concept. This is enabled by low cost coherent transceivers with high sensitivity, also furnishing increased splitting ratio and long reach extension. On the other hand, bandwidth demands are highly dynamic, driven by high definition video, cloud-computing traffic, next generation mobile networks and emerging Internet of Things (IoT). To support this dynamic pattern, reconfigurable capabilities are to be delivered to access and metro networks. In this paper we propose a flexible design of an UDWDM-PON, which adapts the available bandwidth to different classes of services and users, envisioning elastic flexible WDM grids for spectral efficiency and optimized metro network convergence.
2019 21st International Conference on Transparent Optical Networks (ICTON), 2019
Bandwidth demands are increasing with a high dynamic shape, driven by high definition video, clou... more Bandwidth demands are increasing with a high dynamic shape, driven by high definition video, cloud-computing, business services, Internet of Things (IoT) and emerging next generation mobile networks like 5G. To support this variable pattern, reconfigurable capabilities are to be delivered to access and metro networks. 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. In this paper, we propose a versatile metro-access network integrating FTTH, enterprises, IoT and 5G services. To achieve a high sensitivity and bandwidth efficiency, we will use coherent transceivers and Ultra Dense Wavelength Division Multiplexing (UDWDM), which has been envisioned for future PONs and metro networks to support the increase of access traffic.
OFC/IOOC . Technical Digest. Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication
2010 12th International Conference on Transparent Optical Networks, 2010
ABSTRACT Gigabit-capable PON (GPON) is the optical access standard being deployed by many incumbe... more ABSTRACT 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.
2009 11th International Conference on Transparent Optical Networks, 2009
The emerging high bandwidth and on-demand user applications require improvements in capacity, con... more 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. Keywords: passive optical network (PON), hybrid WDM/TDM, Optical burst switching (OBS), metropolitan area network (MAN), reconfigurable optical add drop multiplexers (ROADMs).
2011 13th International Conference on Transparent Optical Networks, 2011
In this paper, offered and new broadband services for residential customers are considered in Pas... more In this paper, offered and new broadband services for residential customers are considered in Passive Optical Networks (PONs). The user bit rates together with QoS requirements are evaluated for the availability of the services in the PONs, according to the number of users and the network bit rates deployed. Traffic forecast is also estimated for the next future access services evolution and for the dimensioning of the optical access networks, taking into account the required bit rates and the number of users involved.
We explore a new wavelength management for ultra-dense WDM-PONs with randomly distributed ONU wav... more We explore a new wavelength management for ultra-dense WDM-PONs with randomly distributed ONU wavelengths, controlled with limited thermal tunability. Static and dynamic wavelength assignment paradigms and heuristic assignment schemes for spectrum management are proposed, simulated and compared. ONU acceptances in activation processes and ONU availability ratios up to 99.99% are obtained in standard environmental conditions.
2013 15th International Conference on Transparent Optical Networks (ICTON), 2013
ABSTRACT Long-Reach (LR) extension is a promising scheme for future next generation access networ... more ABSTRACT 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.
2007 9th International Conference on Transparent Optical Networks, 2007
ABSTRACT To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user... more ABSTRACT To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in an access Passive Optical Network (PON), the use of a Reflective-ONU (R-ONU) is a good choice for up-data transmission. An optical carrier is sent by the Optical Line Terminal (OLT) at the Central Office, and a device at the ONU modulates the carrier with the upstream data. This allows all ONUs to be equal and colorless, without a light source in a Hybrid WDM/TDM architecture. The Dynamic Bandwidth Allocation (DBA) is placed at the OLT, where lasers and photodetectors are shared by all R-ONUs. The OLT laser and photodetector employed in an up-data transmission must be tuned for each ONU and a particular Round Trip Time (RTT) set, which is twice the propagation time from OLT to ONU. When an R-ONU is served by a laser, the photodetector must also be available after the RTT to demodulate the up-data. We investigate the importance of the impact of large different distances OLT-ONUs in the traffic characteristics under a DBA with a proposed novel nesting algorithm and Quality of Service (QoS).
To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in... more To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in an access Passive Optical Network (PON), the use of a Reflective-ONU (R-ONU) is a good choice for up-data transmission. An optical carrier is sent by the Optical Line Terminal (OLT) at the Central Office, and a device at the ONU modulates the carrier with the upstream data. This allows all ONUs to be equal and colorless, without a light source in a Hybrid WDM/TDM architecture. A Dynamic Bandwidth Allocation is placed at the OLT, managing the lasers and photodetectors shared by all R-ONUs. The OLT laser and photodetector employed in an up-data transmission must be tuned for each ONU and a particular Round Trip Time (RTT), which is twice the propagation time from OLT to ONU. When an R-ONU is served by a laser, the photodetector must also be available after the RTT to demodulate the up-data. We propose a novel nesting ranging algorithm to deal with large different distances OLT-ONUs avoiding collisions and minimizing the delay under Priority Queuing with Quality of Service (QoS).
ABSTRACT Long-Reach (LR) extension is a promising scenario for future next generation access netw... more ABSTRACT Long-Reach (LR) extension is a promising scenario 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 OLT and ONUs, inefficiency occurs in the Dynamic Bandwidth Allocation (DBA) upstream protocols. To solve this drawback, a new efficient DBA protocol, named GPON Redundancy Eraser Algorithm for Long-Reach (GREAL), is proposed, removing the redundancy caused by an ONU polling cycle or Scheduling Interval (SI) smaller than the Round-Trip-Time (RTT), while providing also multi-service QoS. This algorithm is independent of the SI and uses real data queuing information without prediction, achieving a great enhancement in bandwidth utilization. Nevertheless, prediction techniques can be used together with GREAL algorithm, improving the DBA protocol and the bandwidth management.
A new all-optical access-metro network interface based on optical burst switching (OBS) is propos... more A new all-optical access-metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access-metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access-metro interface and architectures. Index Terms-Dynamic bandwidth allocation (DBA), metropolitan area network (MAN), optical burst switching (OBS), passive optical networks (PONs), quality of service (QoS).
Abstract Future transport networks will have to cope with the continuous growth of IP traffic. Fu... more Abstract Future transport networks will have to cope with the continuous growth of IP traffic. Furthermore, transport networks need to evolve so as to drastically reduce both deployment costs and operating expenses. A reasonable strategy to achieve this goal consists of ...
A new all-optical access-metro network interface based on optical burst switching (OBS) is propos... more A new all-optical access-metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access-metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access-metro interface and architectures. Index Terms-Dynamic bandwidth allocation (DBA), metropolitan area network (MAN), optical burst switching (OBS), passive optical networks (PONs), quality of service (QoS).
2020 22nd International Conference on Transparent Optical Networks (ICTON), 2020
A coherent WDM-PON achieving ultra-dense spectral allocation is reported. The ONU at user premise... more A coherent WDM-PON achieving ultra-dense spectral allocation is reported. The ONU at user premises is built of coherent transceivers with two paired low-cost DFB lasers, one as local oscillator and the other as transmitter, offering simplicity and economy hardware. The ONU DFB lasers are paired to realize a simple blind activation process, having wavelengths with limited thermal tunability controlled by thermo-electric coolers (TECs). A MAC at the OLT at central office manages the spectrum channel assignment: the OLT furnishes an optical carrier wavelength for the new active ONU to obtain reception in a Dynamic Wavelength Allocation (DWA) by a smart control algorithm, thus assigning a down-channel; subsequently, another paired up-channel is also allocated to the ONU laser transmitter. The MAC can reassign the channels because of interference, collision or any network needs. The channelization of the optical bandwidth is flexible, thus adapting to different user bandwidths, serving all sorts of bit rates and suited for 5G technologies. Measures in an activation process and in channel reassignment have been performed in environment conditions, demonstrating the system feasibility.
2018 European Conference on Networks and Communications (EuCNC), 2018
The Grade of Service (GoS) or ONU rejection probability in coherent UDWDM-PONs with ONU lasers un... more 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.
2018 20th International Conference on Transparent Optical Networks (ICTON), 2018
Ultra Dense Wavelength Division Multiplexing (UDWDM) has been proposed for future Passive Optical... more 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.
2014 16th International Telecommunications Network Strategy and Planning Symposium (Networks), 2014
ABSTRACT We present a novel ONU architecture for coherent UDWDM-PON with randomly distributed ONU... more ABSTRACT We present a novel ONU architecture for coherent UDWDM-PON with randomly distributed ONU wavelengths. The ONU is built with one or two lasers exhibiting simple limited thermal tunability in a specific optical band, where the wavelengths are managed in a Statistical UDWDM approach. If only one laser is present at the ONU, it serves as both local oscillator for coherent receiver and transmitter in a Half-Duplex transmission mode. When two lasers are equipped, they can work in Full-Duplex transmission mode as receiver or transmitter indistinctly and back-up protection is provided in case of laser fail. Finally, a simple activation process based on Half-Duplex transmission for both lasers and a wavelength monitoring during operation is also proposed.
2017 19th International Conference on Transparent Optical Networks (ICTON), 2017
Ultra-Dense Wavelength Division Multiplexing (UDWDM) is a candidate for future Passive Optical Ne... more Ultra-Dense Wavelength Division Multiplexing (UDWDM) is a candidate for future Passive Optical Networks (PONs) to sustain the increase of access traffic, providing enhanced capacity with point-to-point logical connections while introducing the Wavelength-To-The-User (WTTU) concept. This is enabled by low cost coherent transceivers with high sensitivity, also furnishing increased splitting ratio and long reach extension. On the other hand, bandwidth demands are highly dynamic, driven by high definition video, cloud-computing traffic, next generation mobile networks and emerging Internet of Things (IoT). To support this dynamic pattern, reconfigurable capabilities are to be delivered to access and metro networks. In this paper we propose a flexible design of an UDWDM-PON, which adapts the available bandwidth to different classes of services and users, envisioning elastic flexible WDM grids for spectral efficiency and optimized metro network convergence.
2019 21st International Conference on Transparent Optical Networks (ICTON), 2019
Bandwidth demands are increasing with a high dynamic shape, driven by high definition video, clou... more Bandwidth demands are increasing with a high dynamic shape, driven by high definition video, cloud-computing, business services, Internet of Things (IoT) and emerging next generation mobile networks like 5G. To support this variable pattern, reconfigurable capabilities are to be delivered to access and metro networks. 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. In this paper, we propose a versatile metro-access network integrating FTTH, enterprises, IoT and 5G services. To achieve a high sensitivity and bandwidth efficiency, we will use coherent transceivers and Ultra Dense Wavelength Division Multiplexing (UDWDM), which has been envisioned for future PONs and metro networks to support the increase of access traffic.
OFC/IOOC . Technical Digest. Optical Fiber Communication Conference, 1999, and the International Conference on Integrated Optics and Optical Fiber Communication
2010 12th International Conference on Transparent Optical Networks, 2010
ABSTRACT Gigabit-capable PON (GPON) is the optical access standard being deployed by many incumbe... more ABSTRACT 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.
2009 11th International Conference on Transparent Optical Networks, 2009
The emerging high bandwidth and on-demand user applications require improvements in capacity, con... more 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. Keywords: passive optical network (PON), hybrid WDM/TDM, Optical burst switching (OBS), metropolitan area network (MAN), reconfigurable optical add drop multiplexers (ROADMs).
2011 13th International Conference on Transparent Optical Networks, 2011
In this paper, offered and new broadband services for residential customers are considered in Pas... more In this paper, offered and new broadband services for residential customers are considered in Passive Optical Networks (PONs). The user bit rates together with QoS requirements are evaluated for the availability of the services in the PONs, according to the number of users and the network bit rates deployed. Traffic forecast is also estimated for the next future access services evolution and for the dimensioning of the optical access networks, taking into account the required bit rates and the number of users involved.
We explore a new wavelength management for ultra-dense WDM-PONs with randomly distributed ONU wav... more We explore a new wavelength management for ultra-dense WDM-PONs with randomly distributed ONU wavelengths, controlled with limited thermal tunability. Static and dynamic wavelength assignment paradigms and heuristic assignment schemes for spectrum management are proposed, simulated and compared. ONU acceptances in activation processes and ONU availability ratios up to 99.99% are obtained in standard environmental conditions.
2013 15th International Conference on Transparent Optical Networks (ICTON), 2013
ABSTRACT Long-Reach (LR) extension is a promising scheme for future next generation access networ... more ABSTRACT 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.
2007 9th International Conference on Transparent Optical Networks, 2007
ABSTRACT To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user... more ABSTRACT To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in an access Passive Optical Network (PON), the use of a Reflective-ONU (R-ONU) is a good choice for up-data transmission. An optical carrier is sent by the Optical Line Terminal (OLT) at the Central Office, and a device at the ONU modulates the carrier with the upstream data. This allows all ONUs to be equal and colorless, without a light source in a Hybrid WDM/TDM architecture. The Dynamic Bandwidth Allocation (DBA) is placed at the OLT, where lasers and photodetectors are shared by all R-ONUs. The OLT laser and photodetector employed in an up-data transmission must be tuned for each ONU and a particular Round Trip Time (RTT) set, which is twice the propagation time from OLT to ONU. When an R-ONU is served by a laser, the photodetector must also be available after the RTT to demodulate the up-data. We investigate the importance of the impact of large different distances OLT-ONUs in the traffic characteristics under a DBA with a proposed novel nesting algorithm and Quality of Service (QoS).
To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in... more To reduce costs and cumbersome laser provisioning at the Optical Network Unit (ONU) user level in an access Passive Optical Network (PON), the use of a Reflective-ONU (R-ONU) is a good choice for up-data transmission. An optical carrier is sent by the Optical Line Terminal (OLT) at the Central Office, and a device at the ONU modulates the carrier with the upstream data. This allows all ONUs to be equal and colorless, without a light source in a Hybrid WDM/TDM architecture. A Dynamic Bandwidth Allocation is placed at the OLT, managing the lasers and photodetectors shared by all R-ONUs. The OLT laser and photodetector employed in an up-data transmission must be tuned for each ONU and a particular Round Trip Time (RTT), which is twice the propagation time from OLT to ONU. When an R-ONU is served by a laser, the photodetector must also be available after the RTT to demodulate the up-data. We propose a novel nesting ranging algorithm to deal with large different distances OLT-ONUs avoiding collisions and minimizing the delay under Priority Queuing with Quality of Service (QoS).
ABSTRACT Long-Reach (LR) extension is a promising scenario for future next generation access netw... more ABSTRACT Long-Reach (LR) extension is a promising scenario 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 OLT and ONUs, inefficiency occurs in the Dynamic Bandwidth Allocation (DBA) upstream protocols. To solve this drawback, a new efficient DBA protocol, named GPON Redundancy Eraser Algorithm for Long-Reach (GREAL), is proposed, removing the redundancy caused by an ONU polling cycle or Scheduling Interval (SI) smaller than the Round-Trip-Time (RTT), while providing also multi-service QoS. This algorithm is independent of the SI and uses real data queuing information without prediction, achieving a great enhancement in bandwidth utilization. Nevertheless, prediction techniques can be used together with GREAL algorithm, improving the DBA protocol and the bandwidth management.
A new all-optical access-metro network interface based on optical burst switching (OBS) is propos... more A new all-optical access-metro network interface based on optical burst switching (OBS) is proposed. A hybrid wavelength-division multiplexing/time-division multiplexing (WDM/TDM) access architecture with reflective optical network units (ONUs), an arrayed-waveguide-grating outside plant, and a tunable laser stack at the optical line terminal (OLT) is presented as a solution for the passive optical network. By means of OBS and a dynamic bandwidth allocation (DBA) protocol, which polls the ONUs, the available access bandwidth is managed. All the network intelligence and costly equipment is located at the OLT, where the DBA module is centrally implemented, providing quality of service (QoS). To scale this access network, an optical cross connect (OXC) is then used to attain a large number of ONUs by the same OLT. The hybrid WDM/TDM structure is also extended toward the metropolitan area network (MAN) by introducing the concept of OBS multiplexer (OBS-M). The network element OBS-M bridges the MAN and access networks by offering all-optical cross connection, wavelength conversion, and data signaling. The proposed innovative OBS-M node yields a full optical data network, interfacing access and metro with a geographically distributed access control. The resulting novel access-metro architectures are nonblocking and, with an improved signaling, provide QoS, scalability, and very low latency. Finally, numerical analysis and simulations demonstrate the traffic performance of the proposed access scheme and all-optical access-metro interface and architectures. Index Terms-Dynamic bandwidth allocation (DBA), metropolitan area network (MAN), optical burst switching (OBS), passive optical networks (PONs), quality of service (QoS).
Abstract Future transport networks will have to cope with the continuous growth of IP traffic. Fu... more Abstract Future transport networks will have to cope with the continuous growth of IP traffic. Furthermore, transport networks need to evolve so as to drastically reduce both deployment costs and operating expenses. A reasonable strategy to achieve this goal consists of ...
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