| 1. |
- Chiaraviglio, Luca, et al.
(författare)
-
Minimum Cost Design of Cellular Networks in Rural Areas with UAVs, Optical Rings, Solar Panels and Batteries
- 2019
-
Ingår i: IEEE Transactions on Green Communications and Networking. - 2473-2400. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- Bringing the cellular connectivity in rural zones is a big challenge, due to the large installation costs that are incurred when a legacy cellular network based on fixed Base Stations (BSs) is deployed. To tackle this aspect, we consider an alternative architecture composed of UAV-based BSs to provide cellular coverage, ground sites to connect the UAVs with the rest of the network, Solar Panels (SPs) and batteries to recharge the UAVs and to power the ground sites, and a ring of optical fiber links to connect the installed sites. We then target the minimization of the installation costs for the considered UAV-based cellular architecture, by taking into account the constraints of UAVs coverage, SPs energy consumption, levels of the batteries and the deployment of the optical ring. After providing the problem formulation, we derive an innovative methodology to ensure that a single ring of installed optical fibers is deployed. Moreover, we propose a new algorithm, called DIARIZE, to practically tackle the problem. Our results, obtained over a set of representative rural scenarios, show that DIARIZE performs very close to the optimal solution, and in general outperforms a reference design based on fixed BSs.
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| 2. |
- Chiaraviglio, Luca, et al.
(författare)
-
Optimal Design of 5G Networks in Rural Zones with UAVs, Optical Rings, Solar Panels and Batteries
- 2018
-
Ingår i: 2018 20TH ANNIVERSARY INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538666050
-
Konferensbidrag (refereegranskat)abstract
- We focus on the problem of designing a 5G network architecture to provide coverage in rural areas. The proposed architecture is composed of 5G Base Stations carried by Unmanned Aerial Vehicles (UAVs), and supported by ground sites interconnected through optical fiber links. We also consider the dimensioning of each site in terms of the number of Solar Panels (SPs) and batteries. We then formulate the problem of cost minimization of the aforementioned architecture, by considering: i) the cost for installing the sites, ii) the costs for installing the SPs and the batteries in each site, iii) the costs for installing the optical fiber links between the installed sites, and iv) the scheduling of the UAVs to serve the rural areas. Our results, obtained over a representative scenario, reveal that the proposed solution is effective in limiting the total costs, while being able to ensure the coverage over the rural areas.
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| 3. |
- Abeywickrama, S., et al.
(författare)
-
Dual-homing based protection for enhanced network availability and resource efficiency
- 2014
-
Ingår i: Asia Communications and Photonics Conference, ACP. - Washington, D.C. : Optica Publishing Group.
-
Konferensbidrag (refereegranskat)abstract
- An approach to enhance core network survivability by utilizing dual-homing capabilities of the access network. Results reveal significant improvements in core network resource utilization and connection availability, suggesting benefits to network operators and service providers.
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| 4. |
- Abeywickrama, S., et al.
(författare)
-
Energy-efficient survivability for core networks using dual-homing
- 2015
-
Ingår i: Asia Communications and Photonics Conference, ACPC 2015. - Washington, D.C. : OSA. - 9781943580064
-
Konferensbidrag (refereegranskat)abstract
- This paper studies the energy efficiency of exploiting dual-homing in access network to provide core network survivability. Simulation results show reduced number of utilized wavelengths, suggesting significant energy saving opportunities in the core network.
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| 5. |
- Abeywickrama, Sandu, et al.
(författare)
-
Protecting core networks with dual-homing: A study on enhanced network availability, resource efficiency, and energy-savings
- 2016
-
Ingår i: Optics Communications. - : Elsevier. - 0030-4018 .- 1873-0310. ; 381, s. 327-335
-
Tidskriftsartikel (refereegranskat)abstract
- Core network survivability affects the reliability performance of telecommunication networks and remains one of the most important network design considerations. This paper critically examines the benefits arising from utilizing dual-homing in the optical access networks to provide resource-efficient protection against link and node failures in the optical core segment. Four novel, heuristic-based RWA algorithms that provide dedicated path protection in networks with dual-homing are proposed and studied. These algorithms protect against different failure scenarios (i.e. single link or node failures) and are implemented with different optimization objectives (i.e., minimization of wavelength usage and path length). Results obtained through simulations and comparison with baseline architectures indicate that exploiting dual-homed architecture in the access segment can bring significant improvements in terms of core network resource usage, connection availability, and power consumption.
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| 6. |
- Adanza, Daniel, et al.
(författare)
-
IntentLLM: An AI Chatbot to Create, Find, and Explain Slice Intents in TeraFlowSDN
- 2024
-
Ingår i: 2024 IEEE 10th International Conference on Network Softwarization, NetSoft 2024. ; , s. 307-309
-
Konferensbidrag (refereegranskat)abstract
- A large language model (LLM) chatbot is integrated within TeraFlowSDN for intent manipulation. The resulting chatbot is capable of understanding the context and is able to carry out three actions: create, find, and explain intents using natural language while being flexible regarding the language used.
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| 7. |
- Ahmed, Jawwad, et al.
(författare)
-
A Dynamic Bulk Provisioning Framework for Concurrent Optimization in PCE-Based WDM Networks
- 2012
-
Ingår i: Journal of Lightwave Technology. - : IEEE. - 0733-8724 .- 1558-2213. ; 30:14, s. 2229-2239
-
Tidskriftsartikel (refereegranskat)abstract
- A centralized network control and management plane, such as the one based on a path computation element (PCE), is highly beneficial in terms of resource optimization in wavelength division multiplexing optical networks. Benefits of centralized provisioning are even more evident when connection requests are provisioned in batches, i.e., they allow a better use of network resources via concurrent optimization. In this study, a dynamic bulk provisioning framework is presented with the objective of optimizing the use of network resources that also presents, as an additional benefit, the ability to yield a reduction of the control plane overhead. The rationale behind the proposed framework is based on a mechanism in which the PCE client is allowed to bundle and simultaneously send multiple labeled switch path (LSP) requests to the PCE where, in turn, several bundles can be concurrently processed together as a single bulk. From the network deployment perspective, a PCE-based network architecture is proposed to practically realize this approach. For dynamic bulk provisioning of optical LSP requests, a time-efficient integer linear programming (ILP) model (LSP BP ILP) is presented to minimize the request blocking, the network resource consumption, and the network congestion. In addition, a heuristic based on a greedy randomized adaptive search procedure (GRASP), namely LSP_BP_GRASP, is also proposed as a scalable alternative. The presented results demonstrate significant advantages of the proposed PCE bulk provisioning framework based on concurrent optimization in terms of reduced blocking probability and control overhead when compared with conventional dynamic connection provisioning approaches processing a single connection request at a time.
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| 8. |
- Ahmed, Jawwad, et al.
(författare)
-
An Optimal Model for LSP Bundle Provisioning in PCE-based WDM Networks
- 2011
-
Ingår i: 2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2011. - Washington : Optical Society of America.
-
Konferensbidrag (refereegranskat)abstract
- A time-efficient resource optimization model for dynamic concurrent provisioning of connection requests at PCE is proposed. It is shown that a significant performance improvement can be achieved without noticeable increase in connection setup-time.
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| 9. |
- Ahmed, Jawwad, et al.
(författare)
-
Benefits of Connection Request Bundling in a PCE-based WDM Network
- 2009
-
Ingår i: Proc. of European Conference on Networks and Optical Communications (NOC).
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Path Computation Element (PCE) concept is considered to be beneficial in the network connection setup operations, especially in optical networks based on wavelength division multiplex (WDM) transport technology. In the PCE paradigm, communication between a node and the PCE is specified by the Path Computation Element Communication Protocol (PCEP). PCEP allows the PCC (Path Computation Client) to send to the PCE more than one LSP (path computation) request at a time, i.e., multiple LSP requests can be bundled together before being sent to the PCE. Enabling bundling, and consequently the concurrent optimization of a large set of LSP requests at the PCE, may result in significant improvements in terms of network optimization and reduced control plane overhead. However, these advantages come at a cost of increased connection setup-delay. This paper explores pros and cons of enabling bundling of LSP requests in terms of both control plane overhead reduction and benefits of sequential vs. concurrent path computation operations. A variety of scenarios are analyzed, including a WDM mesh network providing LSPs with both dedicated and shared path protection. Results demonstrate significant gains in terms of reduced control overhead using LSP bundling, and reduction in blocking probability using concurrent processing of bundled LSP requests at the PCE.
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| 10. |
- Ahmed, Jawwad, et al.
(författare)
-
Bulk provisioning of LSP requests with shared path protection in a PCE-based WDM network
- 2011
-
Ingår i: ONDM 2011 - 15th Conference on Optical Network Design and Modeling. - 9783901882425
-
Konferensbidrag (refereegranskat)abstract
- The Path Computation Element (PCE) is a network entity utilized for network path computation operations, especially useful in optical networks based on wavelength division multiplexing (WDM). In the PCE paradigm, the communication between a node and the PCE is specified by the Path Computation Element Communication Protocol (PCEP). According to PCEP protocol, multiple LSP (Label Switched Path) requests can be bundled together before being sent to the PCE in order to reduce the control overhead. Multiple bundles received by the PCE can then be provisioned at once as a single bulk. Enabling bulk provisioning of LSP requests at the PCE in a concurrent manner can bring significant improvements in terms of higher network resource utilization and control plane overhead reduction. However, these advantages come at a cost of a longer connection setup-time and of an instantaneous increase in the network load, which may lead to a degradation of the network performance, e.g. blocking probability. In this study pros and cons of bulk provisioning are explored in shared path protection (SPP) by comparing sequential and concurrent path computation strategies. An efficient meta-heuristic named GRASP-SPP-BP (Greedy Random Adoptive Search Procedure for Shared Path Protection with Bulk Provisioning) is proposed for concurrent provisioning of primary and shared backup path pairs. GRASP-SPP-BP minimizes the backup resource consumption while requiring minimal path computation time. The presented results demonstrate that, in a SPP network scenario, a significant reduction in the PCEP control overhead, network blocking probability and backup resource consumption can be achieved via LSP bulk provisioning at the PCE with the proposed GRASP-SPP-BP approach.
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| 11. |
- Ahmed, Jawwad, et al.
(författare)
-
Concurrent processing of multiple LSP request bundles on a PCE in a WDM network
- 2010
-
Ingår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC. - New York : IEEE. - 9781557528841 ; , s. 5465298-
-
Konferensbidrag (refereegranskat)abstract
- Concurrent RWA algorithm for differentiated services to process multiple LSP bundles at PCE is proposed. Significant blocking probability reduction has been observed at the expense of slightly increased LSP setup-time compared to a sequential approach.
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| 12. |
- Ahmed, Jawwad, et al.
(författare)
-
Enhancing restoration performance using service relocation in PCE-based resilient optical clouds
- 2014
-
Ingår i: Optical Fiber Communication Conference, OFC 2014. - : Optical Society of America.
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the benefits of dynamic restoration with service relocation in resilient optical clouds. Results from the proposed optimization model show that service availability can be significantly improved by allowing a few service relocations.
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| 13. |
- Ahmed, Jawwad, et al.
(författare)
-
Hybrid Survivability Schemes Achieving High Connection Availability With a Reduced Amount of Backup Resources
- 2013
-
Ingår i: Journal of Optical Communications and Networking. - : The Optical Society of America. - 1943-0620 .- 1943-0639. ; 5:10, s. A152-A161
-
Tidskriftsartikel (refereegranskat)abstract
- Maximizing connection availability in WDM networks is critical because even small disruptions can cause huge data losses. However, there is a trade-off between the level of network survivability and the cost related to the backup resources to be provided. The 100% survivability can be achieved by dedicated path protection with multiple pre-reserved protection paths for each provisioned connection, i.e., DPP (1:N). Unfortunately, the blocking probability performance of DPP (1:N) is negatively affected by the large number of pre-reserved backup wavelengths standing-by unutilized. On the other hand, path restoration (PR)-based solutions ensure good blocking performance at the expense of lower connection availability.The work in this paper aims at finding hybrid network survivability strategies that combine the benefits of both techniques (i.e., high availability with low blocking rate). More specifically, the paper focuses on a double link failure scenario and proposes two strategies. The first one, couples dedicated path protection DPP (1:1) with path restoration (referred to as DPP + PR) to minimize the number of dropped connections. The second scheme adds up the concept of backup reprovisioning (BR), referred to as DPP + BR + PR, in order to further increase the connection availability achieved by DPP + PR. Integer Linear Programming (ILP) models for the implementation of the proposed schemes are formulated. Extensive performance evaluation conducted in a PCE-based WDM network scenario shows that DPP + BR + PR and DPP + PR can significantly lower the blocking probability value compared to DPP (1:2) without compromising too much in terms of connection availability.
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| 14. |
- Ahmed, Jawwad, et al.
(författare)
-
LSP Request Bundling in a PCE-Based WDM Network
- 2009
-
Ingår i: OFC. - Washington, D.C. : IEEE. - 9781557528650 ; , s. 989-991
-
Konferensbidrag (refereegranskat)abstract
- LSP requests may be bundled to improve the network optimization process at the expense of an increased connection setup delay. A detailed study is conducted to evaluate the pros and cons of the bundling approach.
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| 15. |
- Ahmed, Jawwad, et al.
(författare)
-
Survivability strategies for PCE-based WDM networks offering high reliability performance
- 2013
-
Ingår i: National Fiber Optic Engineers Conference, NFOEC 2013. - Washington, D.C. : Optical Society of America.
-
Konferensbidrag (refereegranskat)abstract
- Two approaches based on backup reprovisioning and path restoration are proposed for dynamic failure recovery in survivable, PCE-based, WDM networks. Results show that proposed schemes can achieve high connection availability in double link failure scenarios.
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| 16. |
- Ahmed, Jawwad, et al.
(författare)
-
Traffic re-optimization strategies for dynamically provisioned WDM networks
- 2011
-
Ingår i: ONDM 2011 - 15th Conference on Optical Network Design and Modeling. - Bologna. - 9783901882425
-
Konferensbidrag (refereegranskat)abstract
- In Wavelength Division Multiplexed (WDM) networks with dynamic lightpath provisioning, connection requests are served without any prior knowledge of their arrival and departure times. As time passes, network resources may become fragmented because of the network dynamism. Under these circumstances it is highly beneficial to re-optimize (i.e., de-fragment) the existing lightpath configuration at some specific time instances to improve the network resource utilization and reduce the risk that future connection requests will be blocked. Assuming that this de-fragmentation process occurs during a re-optimization phase, this paper presents a set of strategies which govern the time instances when this re-optimization phase should be triggered as well as a set of strategies to decide which of the currently active lightpaths should be optimized at any given re-optimization phase. These strategies are referred to as when-to-re-optimize (when-t-r) and what-to-re-optimize (what-t-r) strategies, respectively. During the evaluation process particular attention is devoted to study the impact that when-t-r and what-t-r strategies have on the traffic disruption metrics (i.e., number of total disrupted connections, disruption time, reconfiguration time) inherent with the re-optimization process. Based on the evaluation results, it can be concluded that the choice of an optimal "when" and an optimal "what" to re-optimize strategy is dependent upon the performance objective (e.g. lower blocking probability or network disruption) in a given network scenario.
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| 17. |
|
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| 18. |
- Ajmal, Muhammad, et al.
(författare)
-
An Optimization Model for Dynamic Bulk Provisioning in Elastic Optical Networks
- 2014
-
Ingår i: Asia Communications and Photonics Conference 2014. - : Optics Info Base, Optical Society of America. - 9781557528520 ; , s. AF3E.6-
-
Konferensbidrag (refereegranskat)abstract
- We investigate benefits of setup-delay tolerance in elastic optical networks and propose an optimization model for dynamic and concurrent connection provisioning. Simulation shows that the proposed strategy offers significant improvement of the network blocking performance.
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| 19. |
- Amato, Elisabetta, et al.
(författare)
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A Resource Sharing Method for Reliable Slice as a Service Provisioning in 5G Metro Networks
- 2021
-
Ingår i: 2021 25th Conference On Optical Network Design And Modelling, ONDM 2021. - 9783903176331 ; , s. 1-3
-
Konferensbidrag (refereegranskat)abstract
- This paper proposes a dynamic slice provisioning analysis in a 5G metro network with reliability guarantees and possible sharing of backup resources. Performance of dedicated (DP) and shared (SP) protection solutions are evaluated with respect to slice resource allocation (i.e., bandwidth and processing units). The main results show a remarkable saving, in terms of slice acceptance rate, by applying SP solutions with respect to conventional DP ones.
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| 20. |
- Araujo, Igor M., et al.
(författare)
-
Availability-Guaranteed Service Function Chain Provisioning with Optional Shared Backups
- 2020
-
Ingår i: 2020 16TH INTERNATIONAL CONFERENCE ON THE DESIGN OF RELIABLE COMMUNICATION NETWORKS DRCN 2020. - : IEEE.
-
Konferensbidrag (refereegranskat)abstract
- The dynamic provisioning of Service Function Chain (SFC) using Virtual Network Functions (VNFs) is a challenging problem, especially for availability-constrained services. The provisioning of backup resources is often used to ensure that availability requirements are fulfilled. However, the assignment of backup resources should be carefully designed to avoid resource inefficiencies as much as possible. This paper proposes the Optional Backup with Shared Path and Shared Function (OBSPSF) strategy, which aims at improving resource efficiency while fulfilling the availability requirements of SFC requests. The strategy uses optional backup provisioning to ensure that backup resources are assigned only when strictly needed (i.e., when the SFC alone does not meet the availability constraint). Moreover, OBSPSF encourages backup sharing (among both connectivity and backup VNFs) to reduce the backup resource overhead. Results show that the strategy can accommodate orders-of-magnitude more services than benchmark heuristics from the literature.
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| 21. |
- Ayoub, Omran, et al.
(författare)
-
Towards Explainable Reinforcement Learning in Optical Networks: The RMSA Use Case
- 2024
-
Ingår i: Conference on Optical Fiber Communication, Technical Digest Series.
-
Konferensbidrag (refereegranskat)abstract
- We propose an approach to extract explanations from a trained reinforcement learning agent. Our analysis over three RMSA environment variations shows how the agent uses the input information, increasing our understanding of its learned policy.
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| 22. |
- Billenahalli, Shreejith, et al.
(författare)
-
A wavelength sharing and assignment heuristic to minimize the number of wavelength converters in resilient WDM networks
- 2009
-
Ingår i: Proceedings of the 2009 7th International Workshop on the Design of Reliable Communication Networks, DRCN 2009. - 9781424450473 ; , s. 319-326
-
Konferensbidrag (refereegranskat)abstract
- With the successful introduction of reconfigurable optical add-drop multiplexers (ROADMs) and related technologies, WDM networks are now growing in the number of optical nodes, wavelengths, and lambda services supported. In addition, shared path protection mechanisms - whereby lambda services are allowed to share protection wavelength channels - are possible at the optical (WDM) layer. Efficient strategies must be devised to both determine the set of services that must share a common protection wavelength channel and assign wavelengths to every service. One objective of these strategies is to minimize the total number of wavelength converters (WCs), which are required every time the wavelength continuity constraint cannot be met. This paper presents a scalable and efficient heuristic, whose goal is to minimize the number of WCs in resilient WDM networks supporting static sets of shared path protection lambda services. The heuristic comprises a set of polynomial algorithms that are executed sequentially to obtain a sub-optimal solution. In small size instances of the problem, the heuristic is compared against the optimal solution obtained from ILP formulation. For large size instances - tens of thousands of lambda services and hundreds of nodes - the heuristic yields an average number of WCs that is close to be linear in the number of services, despite the fact that the wavelength sharing factor increases.
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| 23. |
- Cardoso, Diego, et al.
(författare)
-
Joint planning of small cells and optical transport deployment in heterogeneous mobile networks
- 2016
-
Ingår i: Asia Communications and Photonics Conference, ACP. - : OSA - The Optical Society.
-
Konferensbidrag (refereegranskat)abstract
- We investigate how to reduce the deployment cost of heterogeneous mobile networks by joint dimensioning small cells and optical transport resources. The proposed heuristic is able to save 24% of total network deployment cost. Asia Communications and Photonics Conferene (ACP)
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| 24. |
- Cardoso, Evelin, et al.
(författare)
-
A Heuristic Approach for the Design of UAV-Based Disaster Relief in Optical Metro Networks
- 2020
-
Ingår i: International Conference on Transparent Optical Networks. - 2162-7339. - 9781728184234 ; 2020-July, s. 1-5
-
Konferensbidrag (refereegranskat)abstract
- We propose a novel algorithm to dimension the backup elements in an optical metro network, by considering the adoption of Unmanned Aerial Vehicles (UAVs) and wireless interfaces to realize backup wireless links. Our key idea is to efficiently find the set of node pairs that have to be connected by means of multi-hop UAV-based wireless links, which are selected based on the simulation of multiple disaster events. Results, obtained over a set of meaningful scenarios, demonstrate that our solution can greatly reduce the total installation costs compared to a naive approach, which is instead solely tailored to the restoration of the disrupted links in a given disaster scenario.
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| 25. |
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| 26. |
- Cavdar, Cicek, et al.
(författare)
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Design of green optical networks with signal quality guarantee
- 2012
-
Ingår i: IEEE International Conference on Communications. - : IEEE. - 9781457720529 ; , s. 3025-3030
-
Konferensbidrag (refereegranskat)abstract
- Energy consumption of communication networks is growing very fast due to the rapidly increasing traffic demand. Consequently, design of green communication networks gained a lot of attention. In this paper we focus on optical Wavelength Division Multiplexing (WDM) networks, able to support this growing traffic demand. Several energy-aware routing and wavelength assignment (EA-RWA) techniques have been proposed for WDM networks in order to minimize their operational cost. These techniques aim at minimizing the number of active links by packing the traffic as much as possible, thus avoiding the use of lightly loaded links. As a result, EA-RWA techniques may lead to longer routes and to a high utilization on some specific links. This has a detrimental effect on the signal quality of the optical connections, i.e., lightpaths. In this study we quantify the impact of power consumption minimization on the optical signal quality. and address this problem by proposing a combined impairment and energy-aware RWA (IEA-RWA) approach. Towards this goal we developed a complete mathematical model that incorporates both linear and non-linear physical impairments together with an energy efficiency objective. The IEA-RWA problem is formulized as a Mixed Integer Linear Programming (MILP) model where both energy efficiency and signal quality considerations are jointly optimized. By comparing the proposed IEA-RWA approach with existing RWA (IA-RWA and EA-RWA) schemes, we demonstrate that our solution allows for a reduction of energy consumption close to the one obtained by EA-RWA approaches, while still guaranteeing a sufficient level of the optical signal quality.
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| 27. |
- Cerutti, Isabella, et al.
(författare)
-
Plug and Play Networking with Optical Nodes
- 2006
-
Ingår i: ICTON 2006. ; , s. 133-138
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Plug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength routing decisions based on the collected data. This paper discusses what are the open challenges that must be overcome to provide cost effective and performing ad hoc networking solutions based on PPO nodes.
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| 28. |
- Cerutti, Isabella, et al.
(författare)
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Plug and play optical nodes : network functionalities and built-in fiber characterization techniques
- 2007
-
Ingår i: Journal of Optical Networking. - 1536-5379. ; 6:6, s. 642-653
-
Tidskriftsartikel (refereegranskat)abstract
- \textlessp\textgreater\textlessa href$=$"http://www.osa-jon.org/virtual_issue.cfm?vid$=$26"\textgreaterFeature Issue on Photonics in Switching\textless/a\textgreater\textless/p\textgreaterPlug and play optical (PPO) nodes may be used to facilitate the deployment of optical networks. PPO nodes must be able to learn about the signal propagation properties of the surrounding optical fibers and make their wavelength-routing decisions based on the collected data. We discuss what are the open challenges that must be overcome to provide optical networking solutions based on cost-effective PPO nodes. Three possible PPO node hardware architectures with trade-offs in complexity, cost, and functionality are presented along with their built-in fiber characterization techniques.
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| 29. |
- Cervero, A. G., et al.
(författare)
-
Green Wired Networks
- 2015
-
Ingår i: Large-scale Distributed Systems and Energy Efficiency. - Hoboken, NJ, USA : Wiley-Blackwell. - 9781118981122 - 9781118864630 ; , s. 41-80
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter first highlights the significant energy consumption of existing wired communication networks. It considers various means of operating such networks more efficiently. Then, the chapter examines the components that make up a wired communications network and their differing characteristics between the access and core, as well as patterns of traffic behavior. The chapter focuses on static (network planning) and dynamic (traffic-engineering) schemes that can be used to reduce the energy consumption of networks. It also pays attention to a number of challenges/open research questions that need to be resolved before the implementation of such schemes. These include issues with migration and resilience. The chapter then deals with economic-, regulatory-, and business-related methods. Finally, it focuses on the architecture of communication networks and the corresponding relationship with energy usage.
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| 30. |
- Chiaraviglio, Luca, et al.
(författare)
-
5G in rural and low-income areas : Are we ready?
- 2016
-
Ingår i: PROCEEDINGS OF THE 2016 ITU KALEIDOSCOPE ACADEMIC CONFERENCE - ICTS FOR A SUSTAINABLE WORLD (ITU WT). - Piscataway, NJ : IEEE. - 9789261204518 ; , s. 99-106
-
Konferensbidrag (refereegranskat)abstract
- Current trends in telecommunication networks foresee the adoption of the,fifth generation (5G) of wireless networks in the near fixture. However; a large number of people are living without coverage and connectivity. To face this issue, we consider the possibility of deploying 5G networks in rural and low-income zones. After detailing the current state-of-the-art, we consider the main challenges that need to be faced. Moreover; we define the main pillars to follow in order to deploy 5G networks in such zones, as well as a proposal of a future network architecture.
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| 31. |
- Chiaraviglio, Luca, et al.
(författare)
-
Bringing 5G into Rural and Low-Income Areas : Is It Feasible?
- 2017
-
Ingår i: IEEE Communications Standards Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 2471-2825. ; 1:3, s. 50-57
-
Tidskriftsartikel (refereegranskat)abstract
- Nowadays, at least two billion people are experiencing a complete lack of wireless cellular network coverage. These users live in rural areas and low-income regions, where network operators are not keen to invest, mainly due to high capital expenditure and operational expenditure costs, as well as the scarcity of electricity from the grid. We tackle this challenge by proposing a 5G network explicitly designed to serve rural and low-income areas. Our solution investigates the possibility of mounting remote radio heads on top of unmanned aerial vehicles, as well as large cells (LCs) to increase the coverage range. In addition, 5G nodes are powered by solar panels and batteries. Preliminary results, obtained over three representative case studies located in Italy, Cook Islands, and Zimbabwe, show that providing connectivity in rural and low-income areas by means of the proposed 5G architecture is feasible. At the same time, we also show that the monthly subscription fee paid by the users can be kept sufficiently low, that is, less than €1/month in low-income areas, and around €11/month in rural regions.
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| 32. |
- Chiaraviglio, L., et al.
(författare)
-
Impact of energy-efficient techniques on a device lifetime
- 2014
-
Ingår i: 2014 IEEE Online Conference on Green Communications, OnlineGreenComm 2014. - : IEEE conference proceedings. - 9781479973842
-
Konferensbidrag (refereegranskat)abstract
- This paper focuses on the impact that energyefficient techniques have on the component lifetime in optical backbone networks. The study presented in the paper considers in particular the influence that green routing strategies have on the failure rate of Erbium Doped Fiber Amplifiers (EDFAs), i.e., if their lifetime is positively or negatively impacted when putting them into sleep mode in order to reduce their energy consumption. To this end, the paper proposes a model that estimates the failure rate acceleration factor as a function of: (i) for how long and how frequently a device is switched into sleep mode, and (ii) hardware parameters that characterize the device. The proposed model is then evaluated by considering an energyefficient Routing and Wavelength Assignment (RWA) strategy that targets saving energy by putting EDFAs into sleep mode. The results presented in the paper show that energy-efficient techniques may have the potential to lower the failure rate of EDFAs. However, this is true only under specific conditions, i.e., an energy-efficient strategy needs to be carefully planned in order to avoid frequent power state transitions, which result in shortening the lifetime of an EDFA.
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| 33. |
- Chiaraviglio, Luca, et al.
(författare)
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Is Green Networking Beneficial in Terms of Device Lifetime?
- 2015
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Ingår i: IEEE Communications Magazine. - 0163-6804 .- 1558-1896. ; 53:5, s. 232-240
-
Tidskriftsartikel (refereegranskat)abstract
- This article analyzes the impact that sleep mode (SM)-based green strategies have on the reliability performance of optical and cellular network elements. First, we consider a device in isolation (i. e., not plugged into a network in operation), showing how operational temperature and temperature variations, both introduced by SM, impact its lifetime. We then evaluate, from an operational cost perspective, the impact of these lifetime variations, showing that some devices are critical, that is, their achievable energy savings might not cover the potential additional reparation costs resulting from being put in SM too frequently. Moreover, we present a model for evaluating the impact of SM on the lifetime of a device plugged into an operational network. The analysis considers two case studies (one based on the optical backbone and one on cellular networks) showing that the lifetime of a device is influenced by both the hardware parameters, which depend on the specific design of the device, and the SM parameters, which instead depend on the energy-efficient algorithm used, the network topology, and the traffic variations over time. Our results show that (i) the changes in the operational temperature and the frequency of their variation are two crucial aspects to consider while designing a SM-based green strategy, and (ii) the impact of a certain SM-based strategy on the lifetime of network devices is not homogeneous (i. e., it can vary through the network).
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| 34. |
- Chiaraviglio, L., et al.
(författare)
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Towards sustainable and reliable networks with LIFETEL
- 2015
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Ingår i: Proceedings - IEEE INFOCOM. - : IEEE conference proceedings. - 9781467371315 ; , s. 39-40
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Konferensbidrag (refereegranskat)abstract
- We present the LIFETEL project, whose aim is trying to increase the device lifetime in telecommunication networks by exploiting energy-efficient techniques. In particular, we show that the lifetime of a device might increase when it is put in sleep mode. However, the device lifetime might decrease when power state variations (from sleep mode to full power) occur very frequently. Thus, there is a trade-off between the duration of sleep mode and its frequency. Moreover, we report a lifetime analysis for cellular and backbone devices, showing that the electricity saving may be exceeded by the costs due to the fact that devices fail more frequently compared to the situation in which they are always powered on. Thus, we claim that energy-aware network algorithms should be redesigned in order not to impact and to increase (when possible) the lifetime of network devices.
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| 35. |
- Chiasserini, Carla-Fabiana, et al.
(författare)
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An Energy-Efficient Method for Nodes Assignment in Cluster-Based Ad Hoc Networks
- 2004
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Ingår i: Wireless networks. - 1022-0038 .- 1572-8196. ; 10:3, s. 223-231
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Tidskriftsartikel (refereegranskat)abstract
- One of the most critical issues in wireless ad hoc networks is represented by the limited availability of energy within network nodes. Thus, making good use of energy is a must in ad hoc networks. In this paper, we define as network lifetime the time period from the instant when the network starts functioning to the instant when the first network node runs out of energy. Our objective is to devise techniques to maximize the network lifetime in the case of cluster-based systems, which represent a significant sub-set of ad hoc networks. Cluster-based ad hoc networks comprise two types of nodes: cluster-heads and ordinary nodes. Cluster-heads coordinate all transmissions from/to ordinary nodes and forward all traffic in a cluster, either to other nodes in the cluster or to other cluster-heads. In this case, to prolong the network lifetime we must maximize the lifetime of the cluster-heads because they are the critical network element from the energy viewpoint. We propose an original approach to maximize the network lifetime by determining the optimal assignment of nodes to cluster-heads. Given the number of cluster-heads, the complexity of the proposed solution grows linearly with the number of network nodes. The network topology is assumed to be either static or slowly changing. Two working scenarios are considered. In the former, the optimal network configuration from the energy viewpoint is computed only once; in the latter, the network configuration can be periodically updated to adapt to the evolution of the cluster-heads energy status. In both scenarios, the presented solution greatly outperforms the standard assignment of nodes to cluster-heads, based on the minimum transmission power criterion.
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| 36. |
- Chiasserini, Carla-Fabiana, et al.
(författare)
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Energy Efficient Design of Wireless Ad Hoc Networks
- 2006
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Ingår i: NETWORKING 2002. - : Springer Berlin / Heidelberg. ; , s. 376-386
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- One of the most critical issues in wireless ad hoc networks is represented by the limited availability of energy within network nodes. The time period from the instant when the network starts functioning to the instant when the first network node runs out of energy, the so-called network life- time , strictly depends on the system energy efficiency. Our objective is to devise techniques to maximize the network life-time in the case of cluster-based systems, which represent a significant sub-set of ad hoc networks. We propose an original approach to maximize the network life-time by determining the optimal clusters size and the optimal assignment of nodes to cluster-heads. The presented solution greatly outperforms the standard assignment of nodes to cluster-heads, based on the minimum distance criterion.
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| 37. |
- Chincoli, Michele, et al.
(författare)
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Investigating the Energy Savings of Cyclic Sleep with Service Guarantees in Long Reach PONs
- 2012
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Ingår i: Asia Communications and Photonics Conference, ACP. - Washington, D.C. : OSA. - 9781467362740 ; , s. ATh1D.3-
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Konferensbidrag (refereegranskat)abstract
- This paper evaluates what are the conditions, in terms of increased overhead time and number of optical network units (i.e., ONUs), in which cyclic sleep based techniques are effective in Long Reach PONs.
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| 38. |
- Cittadini, Antonio, et al.
(författare)
-
Metformin prevents the development of chronic heart failure in the SHHF rat model.
- 2012
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 61:4, s. 944-53
-
Tidskriftsartikel (refereegranskat)abstract
- Insulin resistance is a recently identified mechanism involved in the pathophysiology of chronic heart failure (CHF). We investigated the effects of two insulin-sensitizing drugs (metformin and rosiglitazone) in a genetic model of spontaneously hypertensive, insulin-resistant rats (SHHF). Thirty SHHF rats were randomized into three treatment groups as follows: 1) metformin (100 mg/kg per day), 2) rosiglitazone (2 mg/kg per day), and 3) no drug. Ten Sprague-Dawley rats served as normal controls. At the end of the treatment period (12 months), the cardiac phenotype was characterized by histology, echocardiography, and isolated perfused heart studies. Metformin attenuated left ventricular (LV) remodeling, as shown by reduced LV volumes, wall stress, perivascular fibrosis, and cardiac lipid accumulation. Metformin improved both systolic and diastolic indices as well as myocardial mechanical efficiency, as shown by improved ability to convert metabolic energy into mechanical work. Metformin induced a marked activation of AMP-activated protein kinase, endothelial nitric oxide synthase, and vascular endothelial growth factor and reduced tumor necrosis factor-α expression and myocyte apoptosis. Rosiglitazone did not affect LV remodeling, increased perivascular fibrosis, and promoted further cardiac lipid accumulation. In conclusion, long-term treatment with metformin, but not with rosiglitazone, prevents the development of severe CHF in the SHHF model by a wide-spectrum interaction that involves molecular, structural, functional, and metabolic-energetic mechanisms.
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| 39. |
- Coelho, Frederico, et al.
(författare)
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Forecasting power load curves from spatial and temporal mobile data
- 2020
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Ingår i: World Review of Science, Technology and Sustainable Development. - 1741-2234 .- 1741-2242. ; 16:1, s. 4-21
-
Tidskriftsartikel (refereegranskat)abstract
- This work aims at applying computational intelligence approaches to telecommunication data, in order to associate mobile data to energy consumption load curves. Clustering methods are applied in order to allow the telecommunication network to infer about its topology and consumption load forecasting. Through an extensive analysis of Telecom Italia dataset and power distribution lines data available for the city of Trento, it was possible to confirm the high correlation between them, mainly when voice data is considered. To a great extent, this correlation can be explained by the fact that cellular communication devices are physically present in the service area of the distribution lines and when people are communicating, they are also consuming energy. Based on the aforementioned dataset, load curves for the city of Trento were constructed having as inputs data from telecommunication transactions. Results show that it is possible to use the telecommunication load as the input to predict the energy load, with the proposed model performing better than the naive predictor in 82% of the tested distribution lines.
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| 40. |
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| 41. |
- da Silva, Carlos Natalino, et al.
(författare)
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Joint Optimization of Failure Management Costs, Electricity Costs, and Operator Revenue in Optical Core Networks
- 2017
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Ingår i: IEEE Transactions on Green Communications and Networking. - : IEEE Press. - 2473-2400 .- 2473-2400. ; PP:99
-
Tidskriftsartikel (refereegranskat)abstract
- We focus on the problem of maximizing profitability in an optical core network by acting on the power states of Optical Line Amplifiers (OLAs) and Line Cards (LCs) operating under varying traffic. Specifically, the profitability metric considered in this work takes into account the electricity costs of OLAs and LCs, the failure management costs derived from the application of power states to the network devices, and the operator revenue. After proving that all terms of the considered profitability function are deeply inter-correlated, we formulate the optimization problem of maximizing the network profitability in an optical core network with multi-period traffic. By solving the proposed formulation on a realistic scenario, we show that it is possible to wisely trade between the considered costs and revenue, and achieve higher network profitability than in the case in which the single terms are considered in isolation, e.g., only electricity consumption or only Failure Management Costs (FMC).
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| 42. |
- Das, Shovan, et al.
(författare)
-
A Link State Advertisement Protocol for Optical Transparency Islands
- 2007
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Ingår i: 2007 WORKSHOP ON HIGH PERFORMANCE SWITCHING AND ROUTING. ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Plug and play optical (PPO) nodes enable fast, re-configurable, and flexible ad hoc deployment of optical networks. Once plugged, the PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. To offer these wavelength routing functionalities to client nodes the PPO nodes must self-adjust to possible changes of the optical physical topology and fiber propagation characteristics. To discover such changes the PPO nodes must make use of a link state advertisement (LSA) protocol that is scalable in the number of plugged PPO nodes. This paper describes a scalable LSA protocol with constrained message flooding to match the limited propagation reach of the optical signal, i.e., the PPO node transparency island (TI). Scalability is thus achieved naturally by limiting the link state advertisement scope to only those PPO nodes that need to receive the link updates. As discussed in the paper, the proposed protocol appears to be a viable solution when the TI size is relatively small, e.g., in optical networks without signal regeneration.
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| 43. |
- Das, Shovan, et al.
(författare)
-
Optical Corridor Routing Protocols
- 2007
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Ingår i: ICTON 2007. ; , s. 188-192
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The scalability of routing and resource advertisement protocols is a key issue in large optical networks. A commonly used solution is based on the hierarchical approach adopted in IP/MPLS-TE networks, i.e., multiple areas or autonomous systems are pre-established to contain the geographical scope of the resource advertisement protocols and the related routing information. With arbitrarily pre-established areas, routing decision might be sub-optimal. Thus, special care must be paid by the network designer to subdivide effectively the network into areas. This paper presents and discusses an alternative routing technique that attempts to improve both optimality and scalability of routing and resource advertisement protocols without requiring the use of manually pre-established areas.
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| 44. |
- Etezadi, Ehsan, 1993, et al.
(författare)
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Deep reinforcement learning for proactive spectrum defragmentation in elastic optical networks [Invited]
- 2023
-
Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 15:10, s. E86-E96
-
Tidskriftsartikel (refereegranskat)abstract
- The immense growth of Internet traffic calls for advanced techniques to enable the dynamic operation of optical networks, efficient use of spectral resources, and automation. In this paper, we investigate the proactive spectrum defragmentation (SD ) problem in elastic optical networks and propose a novel deep reinforcement learning-based framework DeepDefrag to increase spectral usage efficiency. Unlike the conventional, often threshold-based heuristic algorithms that address a subset of the defragmentation related tasks and have limited automation capabilities, DeepDefrag jointly addresses the three main aspects of the SD process: determining when to perform defragmentation, which connections to reconfigure, and which part of the spectrum to reallocate them to. By considering services attributes, spectrum occupancy state expressed by several different fragmentation metrics, as well as reconfiguration cost, DeepDefragmis able to consistently select appropriate reconfiguration actions over the network lifetime and adapt to changing conditions. Extensive simulation results reveal superior performance of the proposed scheme over a scenario with exhaustive defragmentation and a well-known benchmark heuristic from the literature, achieving lower blocking probability at a smaller defragmentation overhead.
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| 45. |
- Etezadi, Ehsan, 1993, et al.
(författare)
-
DeepDefrag: A deep reinforcement learning framework for spectrum defragmentation
- 2022
-
Ingår i: 2022 IEEE Global Communications Conference, GLOBECOM 2022 - Proceedings. ; , s. 3694-3699
-
Konferensbidrag (refereegranskat)abstract
- Exponential growth of bandwidth demand, spurred by emerging network services with diverse characteristics and stringent performance requirements, drives the need for dynamic operation of optical networks, efficient use of spectral resources, and automation. One of the main challenges of dynamic, resource-efficient Elastic Optical Networks (EONs) is spectrum fragmentation. Fragmented, stranded spectrum slots lead to poor resource utilization and increase the blocking probability of incoming service requests. Conventional approaches for Spectrum Defragmentation (SD) apply various criteria to decide when, and which portion of the spectrum to defragment. However, these polices often address only a subset of tasks related to defragmentation, are not adaptable, and have limited automation potential. To address these issues, we propose DeepDefrag, a novel framework based on reinforcement learning that addresses the main aspects of the SD process: determining when to perform defragmentation, which connections to reconfigure, and which part of the spectrum to reallocate them to. DeepDefrag outperforms the well-known Older-First First-Fit (OF-FF) defragmentation heuristic, achieving lower blocking probability under smaller defragmentation overhead.
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| 46. |
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| 47. |
- Etezadi, Ehsan, 1993, et al.
(författare)
-
Proactive Spectrum Defragmentation Leveraging Spectrum Occupancy State Information
- 2023
-
Ingår i: International Conference on Transparent Optical Networks. - 2162-7339. ; 2023-July
-
Konferensbidrag (refereegranskat)abstract
- One of the main obstacles to efficient resource usage under dynamic traffic in elastic optical networks (EONs) is spectrum fragmentation (SF), leading to blocking of incoming service requests. Proactive spectrum defragmentation (SD) approaches periodically reallocate services to ensure better alignment of available spectrum slots across different links and alleviate blocking. The services for reallocation are commonly selected based on their properties, e.g., age, without detailed consideration of prior or posterior spectrum occupancy states. In this paper, we propose a heuristic algorithm for proactive SD that considers different spectrum fragmentation metrics to select services for reallocation. We analyze the relationship between these metrics and the resulting service blocking probability. Simulation results show that the proposed heuristic outperforms the benchmarking proactive SD algorithms from the literature in reducing blocking probability.
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| 48. |
- Famelis, Panagiotis, et al.
(författare)
-
P5: Event-driven Policy Framework for P4-based Traffic Engineering
- 2023
-
Ingår i: Proceedings of the 24th International Conference on High Performance Switching and Routing. - 9781665476409 ; 2023-June
-
Konferensbidrag (refereegranskat)abstract
- We present P5, an event-driven policy framework that allows network operators to realize end-to-end policies on top of P4-based data planes in an intuitive and effective manner. We demonstrate how P5 adheres to a service-level agreement (SLA) by applying P4-based traffic engineering with latency constraints.
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| 49. |
- Farias, Fabricio, et al.
(författare)
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Cost- and energy-efficient backhaul options for heterogeneous mobile network deployments
- 2016
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Ingår i: Photonic network communications. - : AMER INST PHYSICS. - 1387-974X .- 1572-8188. ; 32:3, s. 422-437
-
Tidskriftsartikel (refereegranskat)abstract
- Heterogeneous networks (HetNets) have the potential to cater for the capacity requirements of mobile broadband services at reduced cost and energy consumption levels. One key aspect in HetNets is the role of the backhaul. More specifically, it is crucial for a mobile operator to understand the impact of specific technological and architectural upgrades in the mobile backhaul network on the capital and operational expenditure (i.e., CAPEX and OPEX). This paper proposes a comprehensive methodology that can be used to analyze the total cost of ownership of a number of backhaul options based on fiber, microwave, and copper technologies. The study considers both a Greenfield and a Brownfield scenario and takes into account the mobile broadband capacity requirements for the time period between years 2015 and 2025. From the results presented in the paper it can be concluded that even though microwave and fiber will be predominately used in the future, the possible migration paths leading to such fiber- and microwave-based backhaul scenarios might be different, depending upon factors such as spectrum and license costs, time to deployment, availability of equipment, and required quality of service levels.
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| 50. |
- Farias, Fabricio S., et al.
(författare)
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Green backhauling for heterogeneous mobile access networks : What are the challenges?
- 2013
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Ingår i: 2013 9th International Conference on Information, Communications and Signal Processing (ICICS). - : IEEE Computer Society. - 9781479904334 ; , s. 6782868-
-
Konferensbidrag (refereegranskat)abstract
- Heterogeneous network (HetNet) deployment strategies have the potential to improve the energy efficiency of mobile access networks. One key aspect to consider in HetNets is the impact of the power consumption of the backhaul, i.e., the overall energy efficiency of a HetNet deployment is affected by the backhaul technology and architecture. This paper presents a preliminary assessment of the design challenges of a future green backhaul segment for a HetNet deployment. The study is based on the analysis of the medium term future outlook (i.e., between now and the year 2025) of the main technologies used in todays'* backhaul networks (i.e., fiber, microwave and copper). It can be concluded that, even if there arc no doubts that both microwave and fiber will be predominately used in the future, the possible migration paths leading to such fiber- and microwave-dominated scenarios might be different, depending on factors such as spectrum and license costs, time to deployment, availability of equipment, and required Quality of Service (QoS) levels.
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