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  • 1. De Moor, K.
    et al.
    Andrén, B.
    Guo, Yi
    KTH. Acreo Swedish ICTAB, Sweden.
    Brunnström, K.
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Acreo Swedish ICTAB, Sweden.
    Drott, A.
    Hermann, D.
    Influence of high ambient illuminance and display luminance on readability and subjective preference2015In: Proceedings of SPIE - The International Society for Optical Engineering, 2015Conference paper (Refereed)
    Abstract [en]

    Many devices, such as tablets, smartphones, notebooks, fixed and portable navigation systems are used on a (nearly) daily basis, both in in- and outdoor environments. It is often argued that contextual factors, such as the ambient illuminance in relation to characteristics of the display (e.g., surface treatment, screen reflectance, display luminance...) may have a strong influence on the use of such devices and corresponding user experiences. However, the current understanding of these influence factors is still rather limited. In this work, we therefore focus in particular on the impact of lighting and display luminance on readability, visual performance, subjective experience and preference. A controlled lab study (N=18) with a within-subjects design was performed to evaluate two car displays (one glossy and one matte display) in conditions that simulate bright outdoor lighting conditions. Four ambient luminance levels and three display luminance settings were combined into 7 experimental conditions. More concretely, we investigated for each display: (1) whether and how readability and visual performance varied with the different combinations of ambient luminance and display luminance and (2) whether and how they influenced the subjective experience (through self-reported valence, annoyance, visual fatigue) and preference. The results indicate a limited, yet negative influence of increased ambient luminance and reduced contrast on visual performance and readability for both displays. Similarly, we found that the self-reported valence decreases and annoyance and visual fatigue increase as the contrast ratio decreases and ambient luminance increases. Overall, the impact is clearer for the matte display than for the glossy display. © 2015 SPIE-IS&T.

  • 2.
    Mas Machuca, Carmen
    et al.
    Technical University of Munich.
    Kind, Maria
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Casier, Koen
    Mahloo, Mozhgan
    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).
    Methodology for a cost evaluation of migration toward NGOA networks2013In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 5, no 12, p. 1456-1466Article in journal (Refereed)
    Abstract [en]

    Evolution of optical access networks promises to bring higher bandwidth to more customers. However, this evolution toward so-called next generation optical access (NGOA) networks also introduces additional challenges that operators and/or vendors have to address: how to properly estimate and compare different NGOA architectures and their evolutionary paths in terms of their economics. Calculating the total cost of ownership (TCO) for NGOA networks is a very complex target as it needs to involve good knowledge of the technology, the existing network infrastructure, and any migration-related processes. In this paper a complete methodology is presented for evaluating the TCO of the migration toward a NGOA network. It contains a detailed description of which key aspects have to be considered, which processes they affect, and how they are translated into costs in a logical manner. Finally, it also shows how this methodology has been applied to particular selected cases and how it gives a detailed view of all costs involved in migration. This approach opens up opportunities to cooperate in techno-economic research using it as a base. Both operators and vendors can also utilize this approach to get a useful economic background of their future investments and potential sales.

  • 3.
    Mas Machuca, Carmen
    et al.
    Technical University of Munich.
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Kind, Mario
    Casier, Koen
    Total cost comparison of Next Generation Optical Access Networks with node consolidation2012In: 2012 17th European Conference on Networks and Optical Communications, IEEE conference proceedings, 2012, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Next Generation Optical Access Networks (NGOA) are being evaluated based on their maximum reach, the offered bandwidth per user, their client count and their cost. A complete cost assessment of these architectures should take into account not only the required equipment and infrastructure, but also the continuous cost of fault management, service provisioning, network maintenance, power, etc. This paper presents the models used for the cost assessment. Furthermore, a complete cost assessment of four NGOA architectures at three different types of areas for two different node consolidation degrees is given.

  • 4.
    Mas Machuca, Carmen
    et al.
    Technical University of Munich.
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Verbrugge, Sofie
    Gent University.
    Casier, Koen
    Kind, Mario
    Hülsermann, Ralf
    Krauss, Sandro
    Cost-based assessment of NGOA architectures and its impact in the business model2012In: 11th Conference of Telecommunication, Media and Internet Techno-Economics, Proceedings, Ghent University, Department of Information technology , 2012, p. 1-6Conference paper (Refereed)
  • 5. 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, p. 64-70Article 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.

  • 6. 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.

  • 7.
    Wang, Kun
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Migration Towards Next Generation Optical Access and Transport Networks2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    By 2020 there will be 50 billion connected devices over the Internet. With the fast-increasing data traffic demand in both fixed and mobile networks, network operators need to migrate networks towards next generation solutions. The network migration requires the enormous investment in equipment and infrastructure, while the revenues are not expected to grow significantly. Therefore, one of the main challenges for network operators is to find out a proper cost-effective optical network solution that can match future high capacity demand and flexibly support multiple network services on a common network infrastructure.

    The first part of the thesis addresses the Active Optical Network (AON) and its migration strategies towards Next Generation Optical Access (NGOA) solutions. Several migration strategies are proposed from the perspective of network topology, data plane and control plane. A general methodology for Techno-Economic analysis has been developed and applied to the Total Cost of Ownership (TCO) calculation of different NGOA solutions. The thesis provides a complete cost evaluation of AON migration paths, which can be used by network operators to assess the economic feasibility of network migration.

    A converged Optical Transport Network (OTN) that can serve both fixed and mobile network services is beneficial from the cost-saving perspective. However, the different types of services, require different network performance. The second part of the thesis focuses on the investigation of the converged OTN that can be flexibly and timely adjusted to satisfy varying service conditions. A programmable OTN featured with Wavelength Division Multiplexing (WDM) in the data plane and Software Defined Networking (SDN) in control plane has been proposed. To demonstrate the benefits of the converged OTN, the thesis also provides a multi-domain orchestration architecture for the multiple network services.  The resource orchestration, across three network domains: OTN, mobile network and cloud, enables agile service creation and optimized resource allocation among the multiple domains.

  • 8.
    Wang, Kun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Gavler, Anders
    RISE Acreo.
    Mas Machuca, Carmen
    Technical University of Munich.
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Brunnström, Kjell
    RISE Acreo.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Migration Strategies for FTTx Solutions based on Active Optical Networks2016In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 54, no 2, p. 78-85Article in journal (Refereed)
    Abstract [en]

    AON, one of the most deployed fiber access solutions in Europe, needs to be upgraded in order to satisfy the ever growing bandwidth demand driven by new applications and services. Meanwhile, network providers want to reduce both capital expenditures and operational expenditures to ensure that there is profit coming from their investments. This article proposes several migration strategies for AON from the data plane, topology, and control plane perspectives, and investigates their impact on the total cost of ownership.

  • 9.
    Wang, Kun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Larsen, Claus Popp
    Gavler, Anders
    RISE Acreo.
    Lannoo, Bart
    Chiaroni, Dominique
    Popov, Mikhail
    A Comparative Model and Techno-Economic Analysis of Next Generation AON Ethernet and TDM PON2010In: Network Architectures, Management, and Applications VIII, Optical Society of America, 2010Conference paper (Refereed)
    Abstract [en]

    A global reference model covering next generation active and passive networks has been developed for techno-economic evaluations, and an extensive techno-economic analysis with a focus on CAPEX has been performed for 10G TDM PON and 1G AON - both capable of delivering 1Gbit/s to end-users. Two major cases have been considered: urban and rural at green field deployment. The results show that AON is less expensive than PON solution in urban case while in rural case 10G TDM PON is more competitive.

  • 10.
    Wang, Kun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Mas Machuca, Carmen
    Technical University of Munich.
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Urban, Patryk J.
    Ericsson.
    Gavler, Anders
    RISE Acreo.
    Brunnström, Kjell
    RISE Acreo.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Techno-Economic Analysis of Active Optical Network Migration Toward Next-Generation Optical Access2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 4, p. 327-341Article in journal (Refereed)
    Abstract [en]

    Active optical networks (AONs) have been one of the most deployed fiber access solutions in Europe. However, with the increasing traffic demand, the capacity of the existing AONs is becoming insufficient. For the legacy AONs, there are two major variants of architectures, namely, point-to-point and active star. Considering the different characteristics of these two AON architectures, this paper proposes and analyzes several migration paths toward next-generation optical access (NGOA) networks offering a minimum 300 Mbit/s sustainable bit rate and 1 Gbit/s peak bit rate to every end customer. Furthermore, this paper provides detailed descriptions of the network cost modeling and the processes for AON migration. The total cost of ownership (TCO) is evaluated for the proposed migration paths, taking into account different migration starting times, customer penetration, node consolidation, and business roles in the fiber access networks. The migration from AON to NGOA can be economically feasible. The results indicate that a network provider plays a key business role and is responsible for the major part of the TCO for AON migration. Moreover, performing node consolidation during AON migration can be beneficial from a cost point of view, especially in rural areas.

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