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  • 151.
    Muhammad, Ajmal
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zervas, G.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Filterless networks based on optical white boxes and SDM2016In: ECOC 2016 42th European Conference on Optical Communication Proceedings, September 18 - 22, 2016, Düsseldorf, Germany, Institute of Electrical and Electronics Engineers (IEEE), 2016, 893-895 p.Conference paper (Refereed)
    Abstract [en]

    We propose an agile and programmable multicore fiber (MCF)-based filterless network that exploits the flexibility offered by spatial domain multiplexing and programmable optical switches to eliminate the waste of spectrum due to unfiltered transmission.

  • 152. Muhammad, Ajmal
    et al.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Cerutti, Isabela
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Castoldi, P.
    Reliability Differentiation in Energy Efficient Optical Networks with Shared Path Protection2013In: 2013 IEEE Online Conference on Green Communications, OnlineGreenComm 2013, IEEE , 2013, 64-69 p.Conference paper (Refereed)
    Abstract [en]

    Energy and resource efficiency are two contrasting objectives to optimize in dynamic and survivable optical networks. Known solutions for improving the energy efficiency include the use of the shared path-protection (SPP) mechanism and of a low power consuming mode (i.e., sleep) for protection resources. On the other hand, resource efficiency can be improved by introducing the concept of Differentiated Reliability (DiR) which can be combined with SPP in order to match the level of provisioned protection resources to the reliability requirements for each specific demand. This paper assesses the energy efficiency of the DiR concept combined with SPP and sleep mode support. A multi-objective optimization algorithm is proposed with the intent of jointly optimizing the energy and resource efficiency when dynamically establishing lightpaths with specific reliability levels. Simulation results show that when the proposed multi-objective cost function is properly tuned, not only the SPP-based DiR approach reduces the blocking probability but it is also able to save power for any network load. By enabling sleep mode additional power savings can be achieved at low loads, leading to an overall saving of up to 25%.

  • 153. Natalino, C.
    et al.
    Ahmed, J.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Frances, R.
    A relocation-based heuristic for restoring optical cloud services2014In: 2014 13th International Conference on Optical Communications and Networks, 2014Conference paper (Refereed)
    Abstract [en]

    Optical clouds allow for an integrated management of optical transport and cloud resources (e.g., storage and computing resources running on datacenters). In this paradigm the concept of service relocation (i.e., the ability to re-allocate to a different datacenter node an already provisioned cloud service) offers a new way to restore the network upon failure. This paper presents a heuristic (called H-RELOCATION) based on the service relocation concept to be used for the dynamic restoration of optical cloud services. Upon the occurrence of a network failure, H-RELOCATION solves the routing and resource (i.e., transport plus cloud) allocation problem for each disrupted cloud service allowing, if necessary, to relocate some cloud services to different datacenter nodes. The proposed strategy is benchmarked against two optimal restoration strategies based on Integer Linear Programming (ILP) formulations, the first one without and the second one with the ability to use the service relocation idea. Simulation results show that H-RELOCATION offers performance (i.e., blocking probability, restorability levels and number of required relocations) very close to the optimum, offering on the other hand, a significant reduction in the processing time required for each successfully restored cloud service.

  • 154.
    Natalino, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chiaraviglio, L.
    Idzikowski, F.
    Francês, C. R. L.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Optimal lifetime-aware operation of green optical backbone networks2016In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, ISSN 0733-8716, Vol. 34, no 12, 3915-3926 p., 2611879Article in journal (Refereed)
    Abstract [en]

    This paper targets the lifetime-aware management of a set of optical line amplifiers (OLAs) in an optical network exploiting sleep mode (SM) in order to save energy. We first present a simple model to predict the OLA lifetime. We then provide different mixed-integer linear programming (MILP) formulations, which jointly consider energy saving and lifetime. The proposed MILP formulations are then solved on different realistic scenarios, by taking into account the spatial and temporal variations of traffic demands. Results show that our lifetime-aware approach outperforms classical energy saving ILP formulations, which instead tend to notably decrease the OLA lifetime. More important, the proposed approaches can achieve a good lifetime performance without consuming significantly more energy than purely energy-aware strategies.

  • 155.
    Natalino, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chiaraviglio, Luca
    Idzikowski, Filip
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Listani, Marco
    Carlos, Frances
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Lifetime-Aware Provisioning in Green Optical Backbone Networks2016In: 2016 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), Optical Society of America, 2016Conference paper (Refereed)
    Abstract [en]

    We present a framework able to limit the device lifetime degradation in optical backbone networks using sleep-mode-based green strategies. Results show that our approach manages the lifetime while not compromising significantly the energy saving performance. 

  • 156.
    Natalino, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Franca, Luis
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Frances, Carlos R. L.
    Costa, Joao C. W. A.
    Dimensioning Optical Clouds with Shared-Path Shared-Computing (SPSC) Protection2015In: High Performance Switching and Routing (HPSR), 2015 IEEE 16th International Conference on, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    Service relocation represents a promising strategy to provide flexible and resource efficient resiliency from link failures in the optical cloud environment. However, when a failure affects a node hosting a datacenter (DC), service relocation from the affected DC is not possible. One alternative to protect against DC failures relies on using design strategies that duplicate the IT (i.e., storage and processing) resources in a backup DC at the expense of increasing resource overbuild (i.e., cost) of the network. This work proposes a dimensioning strategy based on the shared-path shared-computing (SPSC) concept able to protect against any single link, server, or DC failure scenario with minimal resource overbuild for the network and IT infrastructures. SPSC is based on the intuition that only storage units need complete replication in backup DC, while processing units can be instantiated only after the occurrence of a failure, leaving the design strategy some leeway to minimize their number. As result, the proposed SPSC design shows a considerable reduction in the amount of backup resources when compared to the dedicated protection strategies.

  • 157.
    Natalino, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Spadaro, Salvatore
    Costa, Joao
    Carlos, Frances
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Restoration in Optical Cloud Networks With Relocation and Services Differentiation2016In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, no 2, 100-111 p.Article in journal (Refereed)
    Abstract [en]

    Optical cloud networks allow for the integrated management of both optical and IT resources. In this paradigm, cloud services can be provisioned in an anycast fashion; i.e., only the source node asking for a service is specified, while it is up to the cloud control/management system to select the most suitable destination data center (DC) node. During the cloud service provisioning process, resiliency is crucial in order to guarantee continuous network operations also in the presence of failures. On the one hand, a survivability strategy needs to be able to meet the availability requirements of each specific cloud service, while on the other hand it must be efficient in using backup resources. This paper proposes a restoration-based survivability strategy, which combines the benefits of both cloud service relocation and service differentiation concepts. The former is used to enhance the restorability performance (i.e., the percentage of successfully restored cloud services) offered by restoration, while the latter ensures that critical services are given the proper consideration while backup resources are assigned. The paper proposes both an integer linear programming (ILP) formulation, which guarantees optimal results, and a heuristic, which trades the optimality of the solution achieved by the ILP for faster processing times. Simulation results show that the average service availability and restorability performance obtained by both the ILP and the heuristic are very close to that achievable using a protection-based strategy, but with the inherent benefit, in terms of efficient use of resources, offered by a restoration-based approach.

  • 158. Nooruzzaman, Md
    et al.
    Alloune, Nabih
    Nabet, Feriel
    Archambault, Emile
    Tremblay, Christine
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Littlewood, Paul
    Bélanger, Michel
    Agile filterless submarine networks2016Conference paper (Refereed)
  • 159. Nooruzzaman, Md.
    et al.
    Alloune, Nabih
    Nabet, Feriel
    Xu, Zhenyu
    Archambault, Emile
    Tremblay, Christine
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Littlewood, Paul
    Belanger, Michel P.
    Filterless Architecture for Coherent Undersea Networks2015In: 2015 INTERNATIONAL CONFERENCE ON OPTICAL NETWORK DESIGN AND MODELING (ONDM), IEEE , 2015, 68-73 p.Conference paper (Refereed)
    Abstract [en]

    Active photonic switching components, such as reconfigurable optical add/drop multiplexers (ROADMs), cannot be deployed at the branching units (BUs) in submarine networks, which limits the flexibility of the undersea networks. In this regard, the filterless optical network architecture based on passive broadcast-and-select nodes and coherent transceivers at the edge terminals can be considered as a promising solution. In this paper we propose and evaluate a filterless network architecture for a trunk and branch undersea network topology. The performance is compared with a conventional solution in terms of cost and wavelength consumption. And it is shown that the filterless architecture can bring significant cost savings for both the terminals and line equipment while offering the same agility as the conventional network architecture.

  • 160. Nooruzzaman, Md
    et al.
    Nabet, Nabet
    Alloune, Nabih
    Archambault, Emile
    Tremblay, Christine
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    Wosinska, Lena
    Littlewood, Paul
    Bélanger, Michel
    Resource Savings Using Gridless Submarine Networks based on Filterless Coherent Transmission Technologies2016Conference paper (Refereed)
  • 161. Ozolins, O
    et al.
    Pang, Xiaodan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE ACREO AB.
    Olmedo, M. Iglesias
    KTH, School of Information and Communication Technology (ICT).
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT).
    Udalcovs, A
    Navarro, J R
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Westergren, Urban
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Jacobsen, G
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    High-speed optical interconnects with integrated externally modulated laser2017In: Transparent Optical Networks (ICTON), 2017 19th International Conference on, Institute of Electrical and Electronics Engineers (IEEE), 2017, 1-1 p.Conference paper (Refereed)
    Abstract [en]

    The cloud services together with the huge size datasets are driving demand for bandwidth in datacenters [1]. The 400 Gbps client-side links are demanding cost efficient solution: to reduce the number of lanes and increase the bandwidth for a single lane. The intensity modulation and direct-detection systems together with integrated semiconductor lasers and modulators appear as promising solution in four optical lanes at 100G since it reduces complexity, power consumption and costs [2]. However, it requires silicon and InP opto-electronic components with more than 70 GHz bandwidth [3]. In this talk, we report on a cost-efficient integrated externally modulated laser (EML) with high bandwidth for record high-speed intensity modulation and direct detection system demonstration with up to 100G OOK, PAM4/8 and duobinary signaling, as well as analog modulations e.g. DMT, paving the way for high speed multilevel modulation formats [4–6]. Related techniques including digital signal processing algorithms for timing recovery, adaptive/static equalization are also discussed in terms of practical implementation and complexity. In addition, techniques constructively using time domain super-Nyquist image induced aliasing for mitigating modulator driver nonlinearity for high speed DMT transmission will be presented [6], [7].

  • 162. Ozolins, Oskars
    et al.
    Da Ros, Francesco
    Cristofori, Valentina
    Pang, Xiaodan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE ACREO AB.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Chaibi, Mohamed E
    Bramerie, Laurent
    Popov, Sergei
    Galili, Michael
    Oxenløwe, Leif K
    Peucheret, Christophe
    Gunnar, Jacobsen
    Optical spectral reshaping for directly modulated 4-pulse amplitude modulation signals2017In: Transparent Optical Networks (ICTON), 2017 19th International Conference on, Institute of Electrical and Electronics Engineers (IEEE), 2017, 1-1 p.Conference paper (Refereed)
    Abstract [en]

    The tremendous traffic growth in intra/inter-datacenters requires low-cost high-speed integrated solutions [1]. To enable a significantly reduced footprint directly modulated lasers (DMLs) have been proposed instead of large external modulators. However, it is challenging to use DMLs due to their low dispersion tolerance and limited achievable extinction ratio (ER). A promising solution to this problem is optical spectral reshaping (OSR) since it is possible to increase the dispersion tolerance as well as to enhance the achievable ER for both on-of-keying [2] and 4-pulse amplitude modulation (PAM) [3] signals. However, moving to 4-PAM,many of the impressive demonstrations reported so far rely heavily on off-line digital signal processing (DSP), which increases latency, power consumption and cost. In this talk, we report on (i) a detailed numerical analysis on the complex transfer function of the optical filter for optical spectral reshaping in case of pulse amplitude modulation and(ii) an experimental demonstration of real-time dispersion-uncompensated transmission of 10-GBd and 14-GBd 4-PAM signals up to 10- and 26-km SSMF. This is achieved by combining a commercial 10-Gb/s DML with optical spectral shaping, thus removing the need for any complex off-line DSP and improving dispersion tolerance. These achievements are enabled by OSR based on a passive microring resonator fabricated on the SOI platform [4]. Significant improvement in receiver sensitivities was observed for both a 10-GBd signal after 10-km SSMF transmission and 14-GBd with no penalty after 26-km SSMF transmission.

  • 163.
    Pang, Xiaodan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ozolins, Oscar
    Gaiarin, S.
    Kakkar, Aditya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Rodrigo Navarro, J.
    Iglesias Olmedo, M.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Udalcovs, A.
    Westergren, U.
    Zibar, D.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Experimental Study of 1.55-μ m EML-Based Optical IM/DD PAM-4/8 Short Reach Systems2017In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 29, no 6, 523-526 p., 7839925Article in journal (Refereed)
    Abstract [en]

    We experimentally evaluate high-speed intensity modulation/direct detection (IM/DD) transmissions with a 1.55-μ text broadband electro-Absorption modulated laser and pulse amplitude modulations (PAM). We demonstrate 80 Gb/s/ λ PAM-4 and 96 Gb/s/ λ PAM-8 transmissions with low-complexity digital equalizers at the receiver. Performance comparison with different types of equalizers are performed, including linear symbol-spaced feed-forward equalizer (FFE), fractional (half-symbol) spaced FFE and decision feedback equalizer (DFE), with different tap number. It is found that for both cases, a 6-Tap symbol-spaced FFE is sufficient to achieve a stable performance with bit-error-rate below the 7% overhead hard decision forward error correction (7%-OH HD-FEC) threshold over a 4 km standard single mode fiber link. Practical considerations including comparison between adaptive and static equalizer implementation and tolerable fiber chromatic dispersion are discussed.

  • 164.
    Pang, Xiaodan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo AB.
    Ozolins, Oskars
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Storck, Joakim
    Udalcovs, Aleksejs
    Navarro, Jaime Rodrigo
    Kakkar, Aditya
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Maisons, Gregory
    Carras, Mathieu
    Jacobsen, Gunnar
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Lourdudoss, Sebastian
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Gigabit free-space multi-level signal transmission with a mid-infrared quantum cascade laser operating at room temperature2017In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 42, no 18, 3646-3649 p.Article in journal (Refereed)
    Abstract [en]

    Gigabit free-space transmissions are experimentally demon-strated with a quantum cascaded laser (QCL) emitting at mid-wavelength infrared of 4.65 mu m, and a commercial infrared photovoltaic detector. The QCL operating at room temperature is directly modulated using on - off keying and, for the first time, to the best of our knowledge, four-and eight-level pulse amplitude modulations (PAM-4, PAM-8). By applying pre- and post-digital equalizations, we achieve up to 3 Gbit/s line data rate in all three modulation configurations with a bit error rate performance of below the 7% overhead hard decision forward error correction limit of 3.8 x 10(-3). The proposed transmission link also shows a stable operational performance in the lab environment.

  • 165. Paolucci, F.
    et al.
    Uceda, V.
    Sgambelluri, Andrea
    KTH, School of Information and Communication Technology (ICT).
    Cugini, F.
    De Dios, O. G.
    Lopez, V.
    Contreras, L. M.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Iovanna, P.
    Ubaldi, F.
    Pepe, T.
    Castoldi, P.
    Interoperable multi-domain delay-aware provisioning using Segment Routing monitoring and BGP-LS advertisement2016In: ECOC 2016 42th European Conference on Optical Communication Proceedings, September 18 - 22, 2016, Düsseldorf, Germany, Institute of Electrical and Electronics Engineers (IEEE), 2016, 190-192 p.Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates a multi-domain SDN orchestrator using delay information to provision network services using BGP-LS and a novel monitoring system enabled by Segment Routing. Moreover, it is the first implementation and interoperability of the BGP-LS extensions for TE metrics.

  • 166.
    Popov, Sergei
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, Oskars
    Olmedo, Miguel I
    Kakkar, Aditya
    Gaiarin, Simone
    Udalcovs, Aleksejs
    Lin, Rui
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Fotonik och mikrovågsteknik.
    Navarro, Jaime R
    Djupsjöbacka, Anders
    Zibar, Darko
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Jacobsen, Gunnar
    Ultra-Broadband High-Linear Integrated Transmitter for Low Complexity Optical Interconnect Applications2016In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2016Conference paper (Refereed)
    Abstract [en]

    We report on a high-speed optical transmitter using InP-based integrated externally modulated laser for optical interconnect applications with up to 30 dB static extinction ratio and over 100 GHz 3 dB bandwidth with 2 dB ripple. It is evaluated with up to 116 Gbit/s on-offkeying, 4-pulse amplitude modulation (PAM) and up to 105 Gbit/s 8-PAM optical signals with different digital equalization implementations. Low number of taps is required for a high and stable performance. Results reveal that digital equalization significantly boosts the passive optical interconnect scalability.

  • 167. Raffaelli, C.
    et al.
    Tonini, F.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Optimization of Centralized Radio access networks in indoor areas2016In: International Conference on Transparent Optical Networks, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    A Centralized Radio Architecture (CRA) allows for the coordination of the physical layer functions of macro and small cells. Efficient techniques can be introduced based on the CRA concept, but deployment cost could potentially increase if CRA networks are not carefully designed. This paper proposes a number of design strategies aimed at cost minimization for CRA networks in residential areas based on heuristics which easily scale with the number of indoor antennas. A few different algorithms, which aim at reducing the overall amount of equipment to cover the area, are described and compared.

  • 168.
    Raza, Muhammad Rehan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Flexible and Programmable 5G Transport Networks2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The advent of 5th generation of mobile networks (5G) will introduce some new challenges for the transport network. Different strategies can be employed by the network providers to address these challenges with the aim to achieve an efficient utilization of network resources. The most feasible option to achieve this goal is to introduce intelligence in the transport infrastructure by designing a flexible and programmable transport network.

    Network function virtualization (NFV) and dynamic resource sharing (DRS) are two possible techniques for realizing a flexible transport network. NFV allows to dynamically push network functions to different locations in the network, while DRS allows for sharing transport resources in a flexible manner. Both of these strategies can be realized by employing a programmable control framework based on software defined networking (SDN), which has implications on both the network data and control planes. However, this thesis specifically focuses on the data plane aspects of NFV and the control plane aspects of DRS.

    Considering the network caching as a specific example of network function, the data plane aspects of NFV are studied in terms of different architectural options for cache placement in order to see which options are the most efficient in terms of network power consumption and cost. The results presented in this thesis show that placing large-sized caches farther in the network for a large group of users is the most efficient approach.

    The control plane aspects of DRS are analyzed in terms of which provisioning strategy should be used for sharing a limited amount of transport resources. The analysis is presented for both a single-tenant case (i.e., where the role of service and network provider is played by the same entity), and a multi-tenant case (i.e., where a network provider manages the resources assigned to different service providers in an intelligent way). The results show that DRS performs much better than the conventional static approach (i.e., without sharing of resources), which translates into significant cost savings for the network providers.

  • 169.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, M.
    Rostami, A.
    Öhlen, P.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Benefits of programmability in 5G transport networks2017In: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    This paper shows how programmability can improve operators' revenues and it presents a dynamic resource slicing policy that leads to more than one order of magnitude better resource utilization levels than convectional (static) allocation strategies.

  • 170.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Kungliga Tekniska högskolan.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Demonstration of Dynamic Resource Sharing Benefits in an Optical CRAN2016In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, no 8, 621-632 p.Article in journal (Other academic)
    Abstract [en]

    The next generation of mobilecommunication (i.e., 5G) will bring new challengesfor the transport infrastructure, e.g. in terms offlexibility and capacity. The joint orchestration ofradio and transport resources can help to addresssome of these challenges. One example is thepossibility to reconfigure the use of the transportnetwork resources according to the spatial andtemporal variations of the wireless traffic patterns.Using the concept of dynamic resource sharing, alimited pool of transport resources can be sharedamong a large number of radio base stations (RBSs)thus reducing considerably the overall deploymentcost of the transport infrastructure.This paper proposes a provisioning strategy for acentralized radio access network (C-RAN) with anoptical transport whose wavelength resources can bedynamically shared among multiple RBSs. Theproposed strategy utilizes a hierarchical softwaredefined networking (SDN) control plane where aglobal orchestrator optimizes the usage of radio andtransport resources. The benefits of the proposedstrategy are assessed both by simulation and byexperiment via an optical data plane emulatordeveloped for this purpose. It is shown that thedynamic resource sharing can save up to 31.4% oftransport resources compared to a conventionaldimensioning approach, i.e., based onoverprovisioning of wavelength resources.

  • 171.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Rostami, Ahmad
    Ericsson AB, Kista Sweden.
    Skubic, Björn
    Ericsson AB, Kista Sweden.
    Öhlen, Peter
    Ericsson AB, Kista Sweden.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Dynamic Resource Sharing for C-RANs with Joint Orchestration of Radio and Transport2016In: ECOC 2016 42th European Conference on Optical Communication Proceedings, September 18 - 22, 2016, Düsseldorf, Germany, VDE Verlag GmbH, 2016, 1001-1003 p.Conference paper (Refereed)
    Abstract [en]

    We present a resource allocation strategy for centralized radio access network architectures able to adapt to the wireless network capacity requirements. Both simulation and emulation results show that it is possible to reuse up to 33.3% of the transport resources.

  • 172.
    Raza, Muhammad Rehan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    Ericsson AB, Kista Sweden.
    Rostami, Ahmad
    Ericsson AB, Kista Sweden.
    Öhlen, Peter
    Ericsson AB, Kista Sweden.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Benefits of Programmability in 5G Transport Networks2017Conference paper (Refereed)
    Abstract [en]

    This paper shows how programmability can improve operators’ revenues and it presents a dynamic resource slicing policy that leads to more than one order of magnitude better resource utilization levels than convectional (static) allocation strategies.

  • 173.
    Ribera, Carlos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Ayşegül Gençata
    Istanbul Technical University, Department of Computer Engineering.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Multi layer energy-efficiency in IP over WDM networks2012In: 2012 Asia Communications And Photonics Conference (ACP), IEEE , 2012, Vol. 28, no 14, ATh2D.7- p.Conference paper (Refereed)
    Abstract [en]

    We propose an energy-aware Internet Protocol (IP) traffic routing strategy together with a virtual topology adaptation approach to save energy in the IP over WDM networks by following a dynamic daily traffic profile.

  • 174. Rimal, B. P.
    et al.
    Pham Van, Dung
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Ericsson Research, Sweden.
    Maier, M.
    Cloudlet Enhanced Fiber-Wireless Access Networks for Mobile-Edge Computing2017In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 16, no 6, 3601-3618 p., 7883946Article in journal (Refereed)
    Abstract [en]

    This paper proposes to enhance capacity-centric fiber-wireless (FiWi) broadband access networks based on data-centric Ethernet technologies with computation- and storage-centric cloudlets to provide reliable cloud services at the edge of FiWi networks and thereby realize the vision of mobile-edge computing (MEC). To reduce offload delay and prolong battery life of edge devices, a novel cloudlet-aware resource management scheme is proposed that incorporates offloading activities into the underlying FiWi dynamic bandwidth allocation process. The whole system is designed in two time division multiple access layers to enhance the network performance. To allow for the efficient coexistence of FiWi and MEC traffic, the offloaded traffic is scheduled outside the FiWi transmission slots. To thoroughly study the scheme's performance, a comprehensive analytical framework is developed that covers a rich set of performance metrics, including packet delay of both FiWi and MEC traffic, response time efficiency, offload gain-overhead ratio, energy efficiency, and battery life. Analytical results demonstrate the feasibility and effectiveness of the cloudlet-enhanced FiWi networks for MEC by employing the proposed solution. Further, we develop an experimental testbed to validate the accuracy of our analytical model via real-world measurements.

  • 175. Rimal, B. P.
    et al.
    Pham Van, Dung
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Maier, M.
    Mobile-edge computing vs. centralized cloud computing in fiber-wireless access networks2016In: Proceedings - IEEE INFOCOM, Institute of Electrical and Electronics Engineers (IEEE), 2016, 991-996 p.Conference paper (Refereed)
    Abstract [en]

    The advent of Internet of Things and 5G applications renders the need for integration of both centralized cloud computing and emerging mobile-edge computing (MEC) with existing network infrastructures to enhance storage, processing, and caching capabilities in not only centralized but also distributed fashions for supporting both delay-tolerant and mission-critical applications. This paper investigates performance gains of centralized cloud and MEC enabled integrated fiber-wireless (FiWi) access networks. A novel resource management scheme incorporating both centralized cloud and MEC offloading activities into the underlying FiWi dynamic bandwidth allocation process is proposed. An analytical framework is developed to model packet delay, response time efficiency, and gain-offload overhead ratio for both cloud and conventional broadband access traffic. The obtained results demonstrate the feasibility of implementing conventional cloud and MEC in FiWi access networks, while not affecting network performance of broadband access traffic.

  • 176. Rimal, B. P.
    et al.
    Van, Dung Pham
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Maier, M.
    Mobile Edge Computing Empowered Fiber-Wireless Access Networks in the 5G Era2017In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 55, no 2, 192-200 p., 7842434Article in journal (Refereed)
    Abstract [en]

    The expected stringent requirements of future 5G networks such as ultra-low latency, user experience continuity, and high reliability will drive the need for highly localized services within RANs in close proximity to mobile subscribers. In light of this, the mobile edge computing (MEC) concept has emerged, which aims to unite telco, IT, and cloud computing to deliver cloud services directly from the network edge. To facilitate better understanding of MEC, this article first discusses its potential service scenarios and identifies design challenges of MEC-enabled networks. Given the importance of scaling up research in the area of network integration and convergence in support of MEC toward 5G, the article explores the possibilities of empowering integrated fiber-wireless (FiWi) access networks to offer MEC capabilities. More specifically, envisioned design scenarios of MEC over FiWi networks for typical RAN technologies (i.e., WLAN, 4G LTE, LTE-A HetNets) are investigated, accounting for both network architecture and enhanced resource management. The performance of MEC over Ethernet-based FiWi networks in terms of delay, response time efficiency, and battery life of edge devices is then analyzed. The obtained results demonstrate the feasibility and effectiveness of the proposed MEC over FiWi concept.

  • 177.
    Rosa, A. N. F.
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Federal University of Para, Brazil.
    Wiatr, Pawel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Carvalho, S. V.
    Costa, J. C. W. A.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Statistical analysis of blocking probability and fragmentation based on Markov modeling of elastic spectrum allocation on fiber link2015In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 354, 362-373 p.Article in journal (Refereed)
    Abstract [en]

    In Elastic Optical Network (EON), spectrum fragmentation refers to the existence of non-aligned, small-sized blocks of free subcarrier slots in the optical spectrum. Several metrics have been proposed in order to quantify a level of spectrum fragmentation. Approximation methods might be used for estimating average blocking probability and some fragmentation measures, but are so far unable to accurately evaluate the influence of different sizes of:connection requests and do not allow in-depth investigation of blocking events and their relation to fragmentation. The analytical study of the effect of fragmentation on requests' blocking probability is still under explored In this work, we introduce new definitions for blocking that differentiate between the reasons for the blocking events. We developed a framework based on Markov modeling to calculate steady-state probabilities for the different blocking events and to analyze fragmentation related problems in elastic optical links under dynamic traffic conditions. This framework can also be used for evaluation of different definitions of fragmentation in terms of their relation to the blocking probability. We investigate how different allocation request sizes contribute to fragmentation and blocking probability. Moreover, we show to which extend blocking events, due to insufficient amount of available resources, become inevitable and, compared to the amount of blocking events due to fragmented spectrum, we draw conclusions on the possible gains one cart achieve by system defragmentation. We also show how efficient spectrum allocation policies really are in reducing the part of fragmentation that in particular leads to actual blocking events. Simulation experiments are carried out showing good match with our analytical results for blocking probability in a small scale scenario. Simulated blocking probabilities for the different blocking events are provided for a larger scale elastic optical link.

  • 178. Rosa, Adriana
    et al.
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Carvalho, S.
    Costa, J.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Spectrum allocation policy modeling for elastic optical networks2012In: High Capacity Optical Networks and Enabling Technologies (HONET), 2012 9th International Conference on, IEEE , 2012, 242-246 p.Conference paper (Refereed)
    Abstract [en]

    Today, optical transmission technologies are able to support 400Gbps over a single optical channel. However, this capacity cannot fit in the current fixed frequency grid optical spectrum. On the other hand, high rate optical channels have to co-exist with different ranges of line rates in order to serve heterogeneous bandwidth requests from variety of internet applications. Today's fixed rate and rigid frequency grid optical transmission systems cause over provisioning, where usually more spectral resources are provided than necessary.

  • 179. Rostami, A.
    et al.
    Vidal, A.
    Santos, M. A. S.
    Raza, Muhammad Rehan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moradi, F.
    Pechenot, B.
    Ghebretensaé, Z.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Öhlén, P.
    An end-to-end programmable platform for dynamic service creation in 5g networks2017In: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    We demonstrate how SDN and NFV can bring end-to-end programmability to heterogeneous technology domains including optical transport, radio and cloud networks, which can in turn be leveraged for agile and resource-optimized service creation.

  • 180. Rostami, Ahmad
    et al.
    Ohlen, Peter
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ghebretensae, Zere
    Skubic, Bjorn
    Santos, Mateus
    Vidal, Allan
    Orchestration of RAN and Transport Networks for 5G: An SDN Approach2017In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 55, no 4, 64-70 p.Article in journal (Refereed)
    Abstract [en]

    The fifth generation of mobile networks is planned to be commercially available in a few years. The scope of 5G goes beyond introducing new radio interfaces, and will include new services like low-latency industrial applications, as well as new deployment models such as cooperative cells and densification through small cells. An efficient realization of these new features greatly benefit from tight coordination among radio and transport network resources, something that is missing in current networks. In this article, we first present an overview of the benefits and technical requirements of resource coordination across radio and transport networks in the context of 5G. Then, we discuss how SDN principles can bring programmability to both the transport and radio domains, which in turn enables the design of a hierarchical, modular, and programmable control and orchestration plane across the domains. Finally, we introduce two use cases of SDN-based transport and RAN orchestration, and present an experimental implementation of them in a testbed in our lab, which confirms the feasibility and benefits of the proposed orchestration.

  • 181. Rostami, Ahmad
    et al.
    Vidal, Allan
    Santos, Mateus Augusto Silva
    Raza, Muhammad Rehan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moradi, Farnaz
    Pechenot, Bertrand
    Ghebretensae, Zere
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ohlen, Peter
    An End-to-End Programmable Platform for Dynamic Service Creation in 5G Networks2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We demonstrate how SDN and NFV can bring end-to-end programmability to heterogeneous technology domains including optical transport, radio and cloud networks, which can in turn be leveraged for agile and resource-optimized service creation.

  • 182. Rostami, Ahmad
    et al.
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Ghenretensae, Zere
    Öhlen, Peter
    Skubic, Björn
    First Experimental Demonstration of Orchestration of Optical Transport, RAN andCloud based on SDN2015In: Optical Fiber Communication Conference Post Deadline Papers, Optical Society of America , 2015Conference paper (Refereed)
    Abstract [en]

    We design and experimentally demonstrate the first resource orchestrationacross DWDM optical transport, radio access networks (RANs) and cloud domains basedon SDN. The orchestration enables agile service creation and optimized resourceallocation.

  • 183. Ruffini, M.
    et al.
    Achouche, M.
    Arbelaez, A.
    Bonk, R.
    Di Giglio, A.
    Doran, N. J.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Jensen, R.
    Montalvo, J.
    Parsons, N.
    Pfeiffer, T.
    Quesada, L.
    Raack, C.
    Rohde, H.
    Schiano, M.
    Talli, G.
    Townsend, P.
    Wessaly, R.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yin, X.
    Payne, D. B.
    Access and metro network convergence for flexible end-to-end network design [invited]2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 6, 524-535 p., 7947089Article in journal (Refereed)
    Abstract [en]

    This paper reports on the architectural, protocol, physical layer, and integrated testbed demonstrations carried out by the DISCUS FP7 consortium in the area of access-metro network convergence. Our architecture modeling results show the vast potential for cost and power savings that node consolidation can bring. The architecture, however, also recognizes the limits of long-reach transmission for low-latency 5G services and proposes ways to address such shortcomings in future projects. The testbed results, which have been conducted end-toend, across access-metro and core, and have targeted all the layers of the network from the application down to the physical layer, show the practical feasibility of the concepts proposed in the project.

  • 184. Ruffini, M
    et al.
    Payne, D B
    Doran, N J
    Achouche, M
    Parsons, N
    Pfeiffer, T
    Yin, X
    Rohde, H
    Schiano, M
    Ossieur, P
    O’Sullivan, B
    Wessäly, R
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Montalvo, J
    DISCUS: The Distributed Core For Ubiquitous Broadband Access2013In: Future Network and MobileSummit 2013, 2013Conference paper (Refereed)
    Abstract [en]

    A new end to end architecture based on Long-Reach Passive OpticalNetwork (LR-PON) with wireless integration, a distributed core built of opticaltransparency islands and an OpenFlow-based control plane, which is beingdeveloped in the EU project DISCUS, is described in this paper. The maintechnological advances and the network modelling and optimization approach arereported.

  • 185. Ruffini, M.
    et al.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Achouche, M.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Doran, N.
    Farjady, F.
    Montalvo, J.
    Ossieur, P.
    O’Sullivan, B.
    Parsons, N.
    Pfeiffer, T.
    Qiu, Xing-Zhi
    Raack, C.
    Rohde, H.
    Schiano, M.
    Townsend, P.
    Wessaly, R.
    Yin, Xin
    Payne, D. B.
    DISCUS: An End-to-End Solution for Ubiquitous Broadband Optical Access2014In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 52, no 2, S24-S32 p.Article in journal (Refereed)
    Abstract [en]

    Fiber to the premises has promised to increase the capacity in telecommunications access networks for well over 30 years. While it is widely recognized that optical-fiber-based access networks will be a necessity in the shortto medium-term future, its large upfront cost and regulatory issues are pushing many operators to further postpone its deployment, while installing intermediate unambitious solutions such as fiber to the cabinet. Such high investment cost of both network access and core capacity upgrade often derives from poor planning strategies that do not consider the necessity to adequately modify the network architecture to fully exploit the cost benefit that a fiber-centric solution can bring. DISCUS is a European Framework 7 Integrated Project that, building on optical-centric solutions such as long-reach passive optical access and flat optical core, aims to deliver a cost-effective architecture for ubiquitous broadband services. DISCUS analyzes, designs, and demonstrates end-to-end architectures and technologies capable of saving cost and energy by reducing the number of electronic terminations in the network and sharing the deployment costs among a larger number of users compared to current fiber access systems. This article describes the network architecture and the supporting technologies behind DISCUS, giving an overview of the concepts and methodologies that will be used to deliver our end-to-end network solution.

  • 186. Ruffini, Marco
    et al.
    Doran, Nick
    Achouche, Mohand
    Parsons, Nick
    Pfeiffer, Thomas
    Yin, Xin
    Rohde, Harald
    Schiano, Marco
    Ossieur, Peter
    O’Sullivan, Barry
    Wessaly, Roland
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Montalvo, Julio
    Payne, David B.
    DISCUS: End-to-end network design for ubiquitous high speed broadband services2013In: Transparent Optical Networks (ICTON), 2013 15th International Conference on, 2013, 1-5 p.Conference paper (Refereed)
    Abstract [en]

    Fibre-to-the-premises (FTTP) has been long sought as the ultimate solution to satisfy the demand for broadband access in the foreseeable future, and offer distance-independent data rate within access network reach. However, currently deployed FTTP networks have in most cases only replaced the transmission medium, without improving the overall architecture, resulting in deployments that are only cost efficient in densely populated areas (effectively increasing the digital divide). In addition, the large potential increase in access capacity cannot be matched by a similar increase in core capacity at competitive cost, effectively moving the bottleneck from access to core. DISCUS is a European Integrated Project that, building on optical-centric solutions such as Long-Reach Passive Optical access and flat optical core, aims to deliver a cost-effective architecture for ubiquitous broadband services. One of the key features of the project is the end-to-end approach, which promises to deliver a complete network design and a conclusive analysis of its economic viability.

  • 187.
    Ruiz, Marc
    et al.
    Universitat Politècnica de Catalunya.
    Velasco, Luis
    Universitat Politècnica de Catalunya.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    A Linearized Statistical XPM Model for Accurate Q-factor Computation2012In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 16, no 8, 1324-1327 p.Article in journal (Refereed)
    Abstract [en]

    Non-linear physical layer impairments make the mathematical programming formulation of off-line impairment-aware (IA) Routing and Wavelength Assignment (RWA) problem to be non-linear. To alleviate that, this paper presents for the first time a statistical linear model to compute the Cross Phase Modulation (XPM) noise variance. Exhaustive evaluation reveals that the proposed linear model provides an accurate Q-factor estimation. An example of Integer Linear Programming (ILP) formulation integrating the XPM model is also given.

  • 188. Samadi, P.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT).
    Shen, Y.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, K.
    Self-adaptive, multi-rate optical network for geographically distributed metro data centers2017In: 2017 Optical Fiber Communications Conference and Exhibition, OFC 2017 - Proceedings, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    We propose a self-adaptive, multi-rate converged architecture and control-plane for metro-scale inter-data-center networks, enabling live autonomous bandwidth steering. Experimental and numerical evaluations demonstrate up to 5 × and 25% improvements in transmission times and spectrum usage.

  • 189. Samadi, Payman
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Shen, Yiwen
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, Keren
    Flexible Architecture and Autonomous Control Plane for Metro-Scale Geographically Distributed Data Centers2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 6, 1188-1196 p.Article in journal (Refereed)
    Abstract [en]

    Enterprises and cloud providers are moving away from deployment of large-scale data centers and towards smallto mid-sized data centers because of their lower implementation and maintenance costs. An optical metro network is used to provide connectivity among these data centers. The optical network requires flexibility on bandwidth allocation and various levels of Quality of Service to support the new emerging applications and services including the ones enabled by 5G. As a result, next generation optical metro networks face complex control and management issues that needs to be resolved with automation. We present a converged inter/intra data center network architecture with an autonomous control plane for flexible bandwidth allocation. The architecture supports both single-rate and multi-rate data planes with two types of physical layer connections (Background and Dynamic) that provide connections with strict bandwidth and latency requirements. We demonstrate autonomous bandwidth steering between two data centers on our prototype. Leveraging a simulation platform, we show up to 5x lower transmission times and 25% less spectrum usage compared with the single-rate conventional non-converged networks. This is a significant improvement in the data center network performance and energy efficiency.

  • 190. Samadi, Payman
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT).
    Shen, Yiwen
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Bergman, Keren
    Self-Adaptive, Multi-Rate Optical Network for Geographically Distributed Metro Data Centers2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    We propose a self-adaptive, multi-rate converged architecture and control-plane for metro-scale inter-data-center networks, enabling live autonomous bandwidth steering. Experimental and numerical evaluations demonstrate up to 5x and 25% improvements in transmission times and spectrum usage.

  • 191.
    Sgambelluri, Andrea
    et al.
    KTH.
    Milani, A.
    Czentye, J.
    Melian, J.
    Poe, W. Y.
    Tusa, F.
    de Dios, O. G.
    Sonkoly, B.
    Gharbaoui, M.
    Paolucci, F.
    Maini, E.
    Giuliani, G.
    Ramos, A.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Contreras-Murillo, L. M.
    Vaishnavi, I.
    Bernardos Cano, C. J.
    Szabo, R.
    A Multi-Operator Network Service Orchestration Prototype: The 5G Exchange2017In: 2017 OPTICAL FIBER COMMUNICATIONS CONFERENCE AND EXHIBITION (OFC), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    In the context of the 5GEx Project, a Multi-domain Orchestrator is in charge of creating, deploying, and terminating Network Services spanning across multiple-operators. This live demo showcases the main functionalities of the 5GEx system.

  • 192. Shahid, Arslan
    et al.
    Machuca, Carmen Mas
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Comparative Analysis of Protection Schemes for Fixed Mobile Converged Access Networks based on Hybrid PON2015In: 2015 CONFERENCE OF TELECOMMUNICATION, MEDIA AND INTERNET TECHNO-ECONOMICS PROCEEDINGS, 2015Conference paper (Refereed)
    Abstract [en]

    Optical access networks are evolving in order to increase the bandwidth offered to the end users. However, as the delivered bandwidth grows, the data losses due to failures also rise. Moreover, the importance of uninterrupted network access is also growing, which makes network reliability a crucial problem to address. Furthermore, today's access network telecom arena has become very competitive, which forces network operators to reduce costs in order to gain some benefits. Cost reduction in access networks has been shown to be possible by node consolidation and fixed mobile convergence, due to the use of a single access network with different types of user and longer reach. This paper proposes four different protection schemes for converged access network architecture, where hybrid passive optical network is deployed to provide high bandwidth to the end users. The comparison is done in three different types of areas (i.e., Dense Urban, Urban and Rural) with respect to various aspects including connection availability, power consumption, required components, additional fiber and failure impact factor.

  • 193. Shen, X.
    et al.
    He, Sailing
    KTH, School of Electrical Engineering (EES).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Medium access control protocol and resource allocation for passive optical interconnects2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 7, 555-562 p., 8000262Article in journal (Refereed)
    Abstract [en]

    Passive optical interconnects (POIs) have recently been considered as a promising solution to offer high bandwidth and low power consumption for data center networks. This paper proposes a medium access control protocol for a POI based on arrayed waveguide gratings (AWGs) to facilitate efficient collision-free communications. In order to efficiently accommodate bursty traffic generated by the servers in the data center, we develop a tailored dynamic bandwidth allocation (DBA) algorithm, which is able to schedule resources in both time and spectrum. In the simulation, not only the impact of DBA algorithm parameters but also the system configurations, such as wavelength tuning time, line rate, and the size of the interconnect, have been investigated. For a typical link utilization on an optical interconnect at the top of the rack, the proposed resource allocation scheme ensures both low latency (<0.1 ms) and a low frame drop ratio (almost zero).

  • 194. Simsarian, Jesse
    et al.
    Fontaine, Nicolas
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zervas, Georgios
    Photonic Networks and Devices Feature: Introduction2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 4, 243-243 p.Article in journal (Refereed)
    Abstract [en]

    This feature issue, based on the OSA Photonic Networks and Devices (NETWORKS) meeting, part of the Advanced Photonics Congress, showcases the latest progress across the photonic network ecosystem from physical-layer devices to network management solutions.

  • 195. Skorin-Kapov, Nina
    et al.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zsigmond, Szilard
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Physical-Layer Security in Evolving Optical Networks2016In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 54, no 8, 110-117 p.Article in journal (Refereed)
    Abstract [en]

    We are witnessing the evolution of optical networks toward highly heterogeneous, flexible networks with a widening area of application. As the bandwidth and reliability performance requirements of mission-critical applications tighten, and the amount of carried data grows, issues related to optical network security are becoming increasingly important. Optical networks are vulnerable to several types of attacks at the physical layer, typically aimed at disrupting the service or gaining unauthorized access to carried data. Such security breaches can induce financial losses to clients or loss of privacy, or cause network-wide service disruption, possibly leading to huge data and revenue losses. Awareness of system weaknesses and possible attack methods is a prerequisite for designing effective network security solutions. As optical networks evolve, new and changing vulnerabilities must be identified and dealt with efficiently. To this end, this article provides a comprehensive overview of potential physical-layer attack scenarios in current and future optical networks. It then proposes a general security framework, outlining possible strategies for dealing with such attacks, meant to aid in the development of efficient provisioning, monitoring, protection, and restoration schemes in the context of optical-layer security.

  • 196. Skorin-Kapov, Nina
    et al.
    Jirattigalachote, Amonrat
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    An integer linear programming formulation for power equalization placement to limit jamming attack propagation in transparent optical networks2014In: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 7, no 12, 2463-2468 p.Article in journal (Refereed)
    Abstract [en]

    Transparent optical networks can be highly vulnerable to various physical-layer attacks, such as high-power jamming, which can cause widespread service disruption and even service denial. The propagation of such attacks can be thwarted with wavelength-selective attenuators, referred to as power equalizers, installed at the network nodes. However, employing all nodes with power equalization functionality can lead to substantial costs. In previous work, we proposed a heuristic approach for sparse power equalization placement to limit jamming attack propagation cost-effectively. The approach provides suboptimal solutions quickly; however, it does not guarantee optimality. Because placement of such power equalization is a long-term planning problem affecting the capital expenditures of the network operator, solution quality is more critical than execution time. Thus, in this paper, we propose an integer linear programming formulation for the problem to guarantee optimality in terms of the number of power equalizers placed. Evaluation results show that our proposed integer linear programming formulation is able to solve moderately sized problems in reasonable time. These results also support the efficiency of our previously proposed heuristic by confirming its ability to find optimal solutions for the cases tested.

  • 197.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Farias, Fabricio
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Federal University of Para.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Is backhaul becoming a bottleneck for green wireless access networks?2014In: 2014 IEEE International Conference on Communications, ICC 2014, IEEE , 2014, 4029-4035 p.Conference paper (Refereed)
    Abstract [en]

    Mobile operators are facing an exponential traffic growth due to the proliferation of portable devices that require a high-capacity connectivity. This, in turn, leads to a tremendous increase of the energy consumption of wireless access networks. A promising solution to this problem is the concept of heterogeneous networks, which is based on the dense deployment of low-cost and low-power base stations, in addition to the traditional macro cells. However, in such a scenario the energy consumed by the backhaul, which aggregates the traffic from each base station towards the metro/core segment, becomes significant and may limit the advantages of heterogeneous network deployments. This paper aims at assessing the impact of backhaul on the energy consumption of wireless access networks, taking into consideration different data traffic requirements (i.e., from todays to 2020 traffic levels). Three backhaul architectures combining different technologies (i.e., copper, fiber, and microwave) are considered. Results show that backhaul can amount to up to 50% of the power consumption of a wireless access network. On the other hand, hybrid backhaul architectures that combines fiber and microwave performs relatively well in scenarios where the wireless network is characterized by a high small-base-stations penetration rate.

  • 198. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Monti, P.
    Minimum Cost Deployment of Radio and Transport Resources in Centralized Radio Architectures2016In: 2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

    The traffic in mobile access networks is increasing at an exponential rate, with the majority of this traffic being generated indoor. To cope with this trend, heterogeneous network (HetNet) architectures based on the centralized radio architecture (CRA) concept have been recently proposed. A CRA network is able to reach high wireless network performance by centralizing the radio physical layer functions of macro and small cells. On the other hand, a CRA network puts strict latency and capacity requirements on the transport segment, which usually comprises a mixture of fiber- and copper-based infrastructure. These strict constraints may translate into high deployment costs if not carefully addressed. This paper proposes an optimized deployment strategy for CRA networks in residential areas. The objective of the proposed strategy is to contain the total deployment cost by minimizing the number of wireless and transport resources required. We demonstrate that our deployment strategy allows for a significant reduction of the required amount of network components and the overall network cost compared to the existing deployment solutions.

  • 199. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Benefits of joint planning of small cells and fiber backhaul in 5G dense cellular networks2017In: 2017 IEEE International Conference on Communications, ICC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, 7997216Conference paper (Refereed)
    Abstract [en]

    Base station (BS) densification is increasingly adopted by mobile operators in order to support increasing traffic demand. However, a large number of BSs requires many backhaul connections, which may be very expensive. For this reason, provisioning high speed backhaul connections to BSs in a cost-effective way is challenging, and it is important to efficiently utilize an existing fixed network infrastructure if possible. This paper proposes two optimized infrastructure-aware planning strategies for small cells and fiber backhaul. The first strategy is referred to as joint design (JD) and is based on the joint cost minimization of small cells and fiber backhaul. The JD strategy is compared to a traditional design (TD) solution based on a two-step optimization approach. In the latter a cost-optimal small cells placement is identified first, then the corresponding minimum cost fiber backhaul deployment is determined accordingly. A comparison between these two approaches in dense 5G urban scenarios shows that the relative performance of JD and TD largely depends on the expected traffic demand and on the existing infrastructure. In dense urban areas with the average traffic levels expected for the year 2020 and beyond, JD returns up to 50% lower deployment cost in a greenfield scenario, and up to 70% lower deployment cost in a brownfield scenario. Only in areas with extremely high traffic demand (e.g., open-air festivals and stadiums) JD returns deployment costs very similar to TD.

  • 200. Tonini, Federico
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Ericsson Res, Sweden.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, Carla
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Radio and Transport Planning of Centralized Radio Architectures in 5G Indoor Scenarios2017In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 35, no 8, 1837-1848 p.Article in journal (Refereed)
    Abstract [en]

    Providing high capacity to the end users is one of the main challenges for the fifth generation (5G) of mobile networks. The users' habit to consume online contents indoor makes the outdoor-to-indoor capacity provisioning impractical, especially when the high-frequency bands proposed for 5G are employed. The centralized radio architecture (CRA) is an inbuilding solution, which relies on the centralization of baseband processing functions, fully or partly allowing for centralized cell management while providing signals directly inside the buildings. On the other hand, the massive deployment of CRAs in urban areas may yield to unacceptably high installation costs, due to the radio network equipment to be activated. To make CRAs appealing to mobile operators, we propose different deployment strategies to minimize the CRA deployment cost. We define the remote radio unit placement (RRUP) problem and formulate it as an integer linear program, obtaining optimal deployment solutions in small urban residential scenarios. We prove the RRUP problem to be NP-hard, requiring heuristic approaches to solve large problem instances. To this end, we propose an effective and scalable heuristic for minimizing the amount of radio equipment required to deploy CRAs in large urban areas.

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