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  • 101.
    Li, Jun
    et al.
    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).
    Passive Optical Network Based Mobile Backhaul Enabling Ultra-Low Latency for Communications Among Base Stations2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 10, 855-863 p.Article in journal (Refereed)
    Abstract [en]

    Low latency is of key importance for mobile networks to support emerging time-critical applications, such as road traffic safety and efficiency. Meanwhile, a passive optical network (PON) is widely recognized as a promising solution for mobile backhaul networks thanks to its high capacity and low energy consumption. In the conventional PON-based mobile backhaul network, where base stations (BSs) are co-located with optical network units, the traffic between the neighboring BSs that are mainly caused by user mobility has to be first sent to the optical line terminal and even further, e.g., edge nodes of mobile core networks, resulting in high latency, although the adjacent BSs are geographically located close to each other. In this paper, a novel PON-based architecture is proposed for mobile backhaul to enhance the connectivity between neighboring BSs. Meanwhile, a tailored medium access control protocol and dynamic bandwidth allocation algorithm are introduced to support fast inter-BS communications. The results reveal that a low latency (less than 1 ms packet delay) for communications among any adjacent BSs can be achieved in the proposed PON-based mobile backhaul network, demonstrating great potential to support future time-critical applications.

  • 102.
    Li, Jun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Natalino, Carlos
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Van, Dung pham
    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).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Resource Management in Fog-Enhanced Radio Access Network to Support Real-Time Vehicular Services2017In: Proceedings - 2017 IEEE 1st International Conference on Fog and Edge Computing, ICFEC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, 68-74 p., 8014361Conference paper (Refereed)
    Abstract [en]

    With advances in the information and communication technology (ICT), connected vehicles are one of the key enablers to unleash intelligent transportation systems (ITS). On the other hand, the envisioned massive number of connected vehicles raises the need for powerful communication and computation capabilities. As an emerging technique, fog computing is expected to be integrated with existing communication infrastructures, giving rise to a concept of fog-enhanced radio access networks (FeRANs). Such architecture brings computation capabilities closer to vehicular users, thereby reducing communication latency to access services, while making users capable of sharing local environment information for advanced vehicular services. In the FeRANs service migration, where the service is migrated from a source fog node to a target fog node following the vehicle's moving trace, it is necessary for users to access service as close as possible in order to maintain the service continuity and satisfy stringent latency requirements of real-time services. Fog servers, however, need to have sufficient computational resources available to support such migration. Indeed, a fog node typically has limited resources and hence can easily become overloaded when a large number of user requests arrive, e.g., during peak traffic, resulting in degraded performance. This paper addresses resource management in FeRANs with a focus on management strategies at each individual fog node to improve quality of service (QoS), particularly for real-time vehicular services. To this end, the paper proposes two resource management schemes, namely fog resource reservation and fog resource reallocation. In both schemes, real-time vehicular services are prioritized over other services so that their respective vehicular users can access the services with only one hop. Simulation results show that the proposed schemes can effectively improve one-hop access probability for real-time vehicular services implying low delay performance, even when the fog resource is under heavy load.

  • 103. Li, Shuo
    et al.
    Wang, Meiqian
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Overby, Harald
    Wong, Eric W. M.
    Zukerman, Moshe
    Performance Evaluation of a Bufferless OBS/OPS Network With 1+1 Path Protection2015In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, no 20, 2115-2118 p.Article in journal (Refereed)
    Abstract [en]

    In optical burst/packet switched (OBS/OPS) networks, bursts/packets may be dropped because of equipment failures. A widely used mechanism to protect a connection from a single-trunk-failure event is 1 + 1 path protection. We consider a bufferless OBS/OPS network with two types of users: 1) premium (that receive 1 + 1 protection service) and 2) regular (that do not receive such a service). We propose a fast and accurate approximation to evaluate the performance of such OBS/OPS network. The accuracy and scalability of the approximation and the effect of the proportion of the premium users in the network are discussed.

  • 104. Li, Shuo
    et al.
    Zukerman, Moshe
    Wang, Meiqian
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wong, Eric W. M.
    Improving throughput and effective utilization in OBS networks2015In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 18, 222-234 p.Article in journal (Refereed)
    Abstract [en]

    This paper considers two important performance measures that have not received much attention in performance studies of optical burst switching (OBS) networks. The first is the so-called effective utilization which is the proportion of link capacity used by bursts that eventually reach their destinations. The second considers the throughput of individual source-destination pairs that may indicate unfairness and starving connections. Using these performance measures, we evaluate a new proposed contention resolution strategy called EBSL, which is a combination of the Emulated-OBS wavelength reservation scheme, with the two contention resolution strategies - Burst Segmentation and Least Remaining Hop-count First (LRHF). The results show that EBSL can prevent congestion collapse of throughput and effective utilization, and reduce the blocking probability under heavy load conditions. We then add deflection routing to EBSL to further increase the throughput under light and medium traffic load. Finally, we replace LRHF by a fairer version of LRHF in EBSL to provide insights into fairness efficiency and tradeoffs. Overall, we demonstrate that OBS can be enhanced to overcome its known traffic congestion related weaknesses of low throughput, ineffective utilization and unfairness.

  • 105. Licciardello, M.
    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).
    Monti, Paolo
    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).
    Performance evaluation of abstraction models for orchestration of distributed data center networks2017In: 2017 19th International Conference on Transparent Optical Networks (ICTON), IEEE Computer Society, 2017, 8025184Conference paper (Refereed)
    Abstract [en]

    Cloud computing is increasingly based on geographically distributed data centers interconnected by high performance networks. Application of Software Defined Networking (SDN) is studied as an emerging solution to support dynamic network resource management for distributed data centers (DCs) jointly with extensive use of Network Function Virtualization (NFV). SDN/NFV operation takes advantage of orchestration of network control functions according to distributed DCs communication needs. Orchestration relies on a set of logical information related to the underlying infrastructure, called abstraction, which offers different levels of visibility of available resources, depending on the abstraction strategy adopted.

  • 106.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Cheng, Yuxin
    KTH, School of Information and Communication Technology (ICT).
    Guan, Xun
    Tang, Ming
    Liu, Deming
    Chan, Chun-Kit
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Physical-layer network coding for passive optical interconnect in datacenter networks2017In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, no 15, 17788-17797 p.Article in journal (Refereed)
    Abstract [en]

    We introduce physical-layer network coding (PLNC) technique in a passive optical interconnect (POI) architecture for datacenter networks. The implementation of the PLNC in the POI at 2.5 Gb/s and 10Gb/s have been experimentally validated while the gains in terms of network layer performances have been investigated by simulation. The results reveal that in order to realize negligible packet drop, the wavelengths usage can be reduced by half while a significant improvement in packet delay especially under high traffic load can be achieved by employing PLNC over POI.

  • 107.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Huazhong University of Science and Technology, China.
    Cheng, Yuxin
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, M.
    Liu, D.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Physical-layer network coding for passive optical interconnects in datacenter networks2017In: 2017 19th International Conference on Transparent Optical Networks (ICTON), IEEE Computer Society, 2017Conference paper (Refereed)
    Abstract [en]

    We introduce physical-layer network coding for a passive optical interconnect architecture in datacenter networks. Results reveal that half of the wavelengths can be saved to obtain latency in the magnitude of microseconds.

  • 108.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Huazhong University of Science and Technology, China.
    Pang, Xiaodan
    Ozolins, Oskars
    Feng, Zhenhua
    Djupsjöbacka, Anders
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Jacobsen, Gunnar
    Tang, Ming
    Fu, Songnian
    Liu, Deming
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Experimental Validation of Scalability Improvement for Passive Optical Interconnect by Implementing Digital Equalization2016Conference paper (Refereed)
  • 109.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Szczerba, K.
    Agrell, E.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, M.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    To overcome the scalability limitation of passive optical interconnects in datacentres2016In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2016Conference paper (Refereed)
    Abstract [en]

    We propose to add optical amplifier(s) to passive optical interconnect (POI) at top-of-rack in datacentres and validate this approach by introducing impairment constraints into POIs design. It is shown that one amplifier can improve scalability by a factor of 16.

  • 110.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). Huazhong University of Sci&Tech (HUST), China.
    Szczerba, K.
    Agrell, E.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, M.
    Liu, D.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Scalability analysis methodology for passive optical interconnects in data center networks using PAM2017In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 403, 283-289 p.Article in journal (Refereed)
    Abstract [en]

    A framework is developed for modeling the fundamental impairments in optical datacenter interconnects, i.e., the power loss and the receiver noises. This framework makes it possible, to analyze the trade-offs between data rates, modulation order, and number of ports that can be supported in optical interconnect architectures, while guaranteeing that the required signal-to-noise ratios are satisfied. To the best of our knowledge, this important assessment methodology is not yet available. As a case study, the trade-offs are investigated for three coupler-based top-of-rack interconnect architectures, which suffer from serious insertion loss. The results show that using single-port transceivers with 10 GHz bandwidth, avalanche photodiode detectors, and quadratical pulse amplitude modulation, more than 500 ports can be supported.

  • 111.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Huazhong University of Sci&Tech (HUST), China.
    Szczerba, Kraysztof
    Agrell, Erik
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, Ming
    Liu, Deming
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Scalability Analysis of Coupler Based Optical InterconnectsIn: IEEE Photonics Journal, ISSN 1097-5764, E-ISSN 1943-0655Article in journal (Other academic)
  • 112.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Huazhong University of Science and Technology, China.
    Szczerba, Krzysztof
    Agrell, Erik
    Wosinska, Lena
    Tang, Ming
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    To Overcome the Scalability Limitation of Passive Optical Interconnects in Data centres2016Manuscript (preprint) (Other academic)
  • 113.
    Lin, Rui
    et al.
    Huazhong University of Science and Technology, China.
    Tang, M.
    Wang, R.
    Feng, Z.
    Fu, S.
    Liu, D.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Shum, P.
    An Ultra-dense Optical Comb Based DWDM-OFDM-PON System2014Conference paper (Refereed)
    Abstract [en]

    We proposed and demonstrated an ultra-dense optical comb based DWDM-OFDM-PON scheme. At the optical line terminal (OLT), a cost-effective optical frequency comb generator (OFCG) is proposed and achieved as the multi-wavelength optical source. The OFCG is capable to provide multiple channels with reconfigurable wavelength spacing for ultra-dense WDM-PON based access network. In our scheme, OFDMsignal with multi-level modulation will be encoded into the OFCG lines for the downstream transmission to enhance the spectral efficiency while the OFDM signal will be remodulated by OOK data for the upstream transmission due to its ease of implementation in optical network unit (ONU) side. In experiments, we demonstrated that 10 optical lines with 25 GHz channel spacing are generated and they were modulated by 2.5-GB/s QPSK-OFDM for the downlink signal transmission. We also demonstrated that the multiple wavelengths from the OFCG.

  • 114.
    Lin, Rui
    et al.
    KTH.
    Tang, M.
    Wang, R.
    Feng, Z.
    Fu, S.
    Liu, D.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Shum, P.
    An Ultra-dense Optical Comb Based DWDM-OFDM-PON System2014Conference paper (Refereed)
    Abstract [en]

    We proposed and demonstrated an ultra-dense optical comb based DWDM-OFDM-PON scheme. At the optical line terminal (OLT), a cost-effective optical frequency comb generator (OFCG) is proposed and achieved as the multi-wavelength optical source. The OFCG is capable to provide multiple channels with reconfigurable wavelength spacing for ultra-dense WDM-PON based access network. In our scheme, OFDMsignal with multi-level modulation will be encoded into the OFCG lines for the downstream transmission to enhance the spectral efficiency while the OFDM signal will be remodulated by OOK data for the upstream transmission due to its ease of implementation in optical network unit (ONU) side. In experiments, we demonstrated that 10 optical lines with 25 GHz channel spacing are generated and they were modulated by 2.5-GB/s QPSK-OFDM for the downlink signal transmission. We also demonstrated that the multiple wavelengths from the OFCG.

  • 115.
    Lin, Rui
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    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).
    Scalability Analysis Methodology for Passive OpticalInterconnects in Data Center Networks Using PAM2016In: IEEE Photonics Journal, ISSN 1097-5764, E-ISSN 1943-0655Article in journal (Other academic)
  • 116. Lorincz, J.
    et al.
    Meo, M.
    Alsusa, E.
    Ruffini, M.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Saavedra, A. G.
    Ho, C. K.
    Conference Report/IEEE OnlineGreenComm 20162017In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 55, no 1, 6-7 p., 7823325Article in journal (Other academic)
  • 117. MacHuca, C. M.
    et al.
    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).
    Cost-efficient protection in TDM PONs2012In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 50, no 8, 110-117 p.Article in journal (Refereed)
    Abstract [en]

    Reliability in optical access networks is becoming a crucial issue for both operators and users due to the enormous increase of capacity and the importance of uninterrupted access to network services. Consequently, the growing number of users requesting penalties for connection interruptions is motivating for investing in protection mechanisms in fiber access networks. The investments involved depend on several aspects such as technology and covered area (population density, distance, type of users, etc.). Moreover, the passive optical network is considered one of the most beneficial fiber access solutions from the capital expenditures point of view; in particular, we are witnessing a wide deployment of TDM PONs. Keeping in mind that cost is a major issue in the access part of the network, in this article we propose a cost-efficient way to provide protection in a TDM PON considering different deployment scenarios in respect to population density in the access network area. The cost efficiency is obtained by taking advantage of investment cost reduction caused by sharing the same duct by both working and protection fibers. In order to evaluate the investment associated with the deployment of the proposed protection schemes, we take into account three different approaches: provide protection in the access network from the beginning, invest initially on an unprotected architecture keeping in mind a future upgrade with protection resources, and roll out an unprotected access network and, if needed in the future, invest in deployment of protection resources. The cost parameters considered in this article include investment in the infrastructure and installation, as well as the operational expenditures associated with failure reparation and service interruption penalties. Our results confirm that the proposed reliable PON architectures can achieve significant reduction of service interruption at very low increase in investment cost, leading to a great decrease of the total cost of ownership. Finally, some useful guidance for cost-efficient deployment of protection in fiber access networks is provided along with a sensitivity study to point out the key cost factors.

  • 118. Machuca, C. M.
    et al.
    Wong, E.
    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).
    Energy consumption and reliability performance of survivable hybrid passive optical converged networks2014In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2014Conference paper (Refereed)
    Abstract [en]

    The paper provides the methodology to evaluate the tradeoff between the consumed energy, the connection availability and the connection interruption time for survivable hybrid passive optical converged networks in different deployment areas.

  • 119.
    Mahloo, Mozhgan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Reliability versus Cost in Next Generation Optical Access Networks2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The ever increasing demands of Internet users caused by the introduction of new high bandwidth applications and online services as well as the growing number of users and devices connected to the Internet, bring many challenges for the operators, especially in the last mile section of the network. Next generation access architectures are expected to offer high sustainable bandwidth per user. They also need to support a much larger service areas to decrease number of current central offices and hence potentially save the network expenditures in the future. Obviously, it requires high capacity and low loss transmission and optical fiber technology is the only future proof candidates for broadband access. Although this technology has already been widely deployed in the core networks, it is hard to use the same expensive devices made for core segment to solve the last mile bottlenecks, due to the low number of users sharing the network resources (and deployment cost). Therefore, the next generation optical access (NGOA) networks need to be designed with consideration of cost efficiency in the first place.

     

    Network reliability is also turning to be an important aspect for the NGOA networks as a consequence of long reach, high client count and new services requiring uninterrupted access. Consequently, new architectures not only need to be cost efficient but also they should fulfill the increasing reliability requirements.

     

    Although several NGOA alternatives have been proposed in the literatures, there is not yet an agreement on a single architecture. As described earlier, network expenditure and reliability performance are the two main factors to be considered. Therefore, this thesis concentrates on finding a suitable alternative for future broadband access by evaluating the reliability performance and total cost of ownership for several NGOA candidates. In particular, in this thesis we analyze the tradeoff between the cost needed to deploy backup resources and the reliability performance improvement obtained by the provided survivability mechanism.

     

    First, we identified the suitable NGOA candidates by comparing two main groups of optical access networks, namely passive optical networks (PONs) and active optical networks (AONs), in terms of cost, reliability performance and power consumption. The initial results have shown that wavelength division multiplexing PON (WDM PON) is the most promising alternative for the NGOA networks because of its high potential capacity, low cost and power consumption. So we continued our studies by investigating two WDM-based PON architectures regarding their cost and reliability performance. The study has also included a proposed fiber layout compatible with these two candidates aiming to minimize the required investment needed to offer protection. Our primary results confirmed that hybrid PON (HPON) is the best alternative for the NGOA networks. Therefore we further analyzed this candidate considering several variants of HPON. The most important components and sections of the HPON, which need to be protected to decrease the impact of each failure in the network have been identified. Based on these outcomes, two resilience architectures protecting the shared part of the HPON were proposed and their reliability performance parameters as well as cost of protection were evaluated. According to the results, using our proposed protection schemes a considerable improvement in reliability performance of the HPON variants can be provided at minor extra investment. We also introduced a cost efficient HPON architecture with different levels of protection for users with various reliability requirements, i.e. the protection of shared parts of the access network for all the connected users and end-to-end resilience scheme for some selected ones (e.g., business users). To gain an overall view on the cost efficiency of the proposed architecture, we evaluated the investment required for deploying these schemes considering several network upgrading paths towards a protected network. Moreover, a sensitivity analysis investigating the influence of network deployments time and the density of the users with higher availability requirements was presented.

     

    In summary, we have shown that HPON is able to fulfill the main NGOA requirements such as high bandwidth per-user, large coverage and client count. The work carried out in the thesis has proved that HPON can also offer high reliability performance while keeping the network expenditures at an acceptable level. Moreover, low power consumption and high flexibility in resource allocation of this architecture, makes it a winning candidate for the NGOA networks. Therefore, HPON is a promising architecture to be deployed as NGOA network in the near future considering the fact that components are soon to be available in the market.

  • 120.
    Mahloo, Mozhgan
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Transport Solutions for Future Broadband Access Networks2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    “Connected society” where everything and everyone are connected at any time and on any location brings new challenges for the network operators. This leads to the need of upgrading the transport networks as the segment of Internet infrastructure connecting the fixed users and mobile base stations to the core/aggregation in order to provide high sustainable bandwidth, as well as supporting a massive number of connected devices. To do this, operators need to change the way that access networks are currently deployed. The future access network technologies will need to support very high capacity and very long distances, which are the inherited characteristics of optical transmission. Hence, optical fiber technology is recognized as the only future proof technology for broadband access.

    Capacity upgrade in the access networks can lead to a huge capacity demand in the backbone network. One promising solution to address this problem, is to keep the local traffic close to the end users as much as possible, and prevent unnecessary propagation of this type of traffic through the backbone. In this way, operators would be able to expand their access network without the significant capacity upgrade in the higher aggregation layers. Motivated by this need, a comprehensive evaluation of optical access networks is carried out in this thesis regarding ability of accommodating local traffic and amount of possible saving in the backbone by implementing locality awareness schemes.

    Meanwhile, next generation optical access (NGOA) networks have to provide high capacity at low cost while fulfilling the increasing reliability requirements of future services and customers. Therefore, finding cost-efficient and reliable alternative for future broadband access is one of the most important contributions of this thesis. We analyzed the tradeoff between the cost needed to deploy backup resources and the reliability performance improvement obtained by the proposed protection mechanism.

    Among different NGOA architectures, hybrid time and wavelength division multiplexing passive optical network (TWDM PON) is considered as a proper candidate providing high capacity and large coverage. Therefore, this approach is further analyzed and several tailored protection schemes with high flexibility are proposed to statisfy different requirements from the residential and business users in the same PON.  The work carried out in the thesis has proved that TWDM PON can also offer high reliability performance while keeping the network expenditures at an acceptable level. Considering some other advantages such as low power consumption and high flexibility in resource allocation of this architecture, it has high potential to be the best candidate for NGOA networks.

     Moreover, new deployments of radio access networks supporting the increasing capacity demand of mobile users lead to the upgrade of the backhaul segment as a part of broadband access infrastructure. Hence, this thesis also contributes with a comprehensive techno-economic evaluation methodology for mobile backhaul. Several technologies are investigated in order to find the most cost-efficient solution for backhauling the high capacity mobile networks.  Finally, a PON-based mobile backhaul with high capacity and low latency has been proposed for handling coordinated multipoint transmission systems in order to achieve high quality of experience for mobile users. 

  • 121.
    Mahloo, Mozhgan
    et al.
    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).
    PON versus AON: Which is the best solution to offload core network by peer-to-peer traffic localization2015In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 15, no 0, 1-9 p.Article in journal (Refereed)
    Abstract [en]

    Abstract Video streaming and video-on-demand are gaining popularity nowadays which dictates a need of bandwidth upgrade for Internet users. Many next generation optical access network architectures have been proposed to meet high capacity requirement on a per-user basis. However, the capacity upgrade in access networks, may lead to a huge traffic growth in the aggregation/core network. One way to avoid this problem is to keep the traffic locally (i.e., inside the access network area) as much as possible. It can be obtained by using locality-aware peer-to-peer (P2P) applications for content distribution and has the potential to offload the core segment. However, various optical access network architectures accommodate the P2P traffic in different ways. Thus, it is important to study these differences in order to identify the best architecture option for capacity offloading in the core network, energy efficiency and network resource utilization. By deploying a proper architecture in the access segment along with an efficient traffic locality aware strategy, the extra investment and capacity upgrade of the expensive core network resources needed to support the future traffic expansion can be minimized. However, to the best of our knowledge this kind of assessment is so far not available. Therefore, in this paper, we analyze the efficiency of supporting locality-aware P2P video distribution algorithm in three main types of optical access network architectures, i.e., active optical network (AON), wavelength division multiplexing passive optical network (WDM PON) and time/wavelength division multiplexing PON (TWDM PON). Our goal is to provide important design guidelines for the next generation broadband access architectures, while minimizing the need for the core network upgrade. We obtain this objective by utilizing the unique characteristics of each access network architecture in accommodating P2P video delivery applications. We have done an extensive literature study and for the first time we have compared performance of these architectures with respect to the amount of the traffic on the links in different aggregation levels, power consumption taking into account sleep mode functionality at the user premises, and required switching capacity in the nodes. Our results reveal that both active and passive architectures have good ability to localize P2P traffic, whereas they show distinct performance with respect to the other aforementioned aspects. This is caused by the different number of aggregation levels, link capacity, and resource allocation protocols. Considering the overall performance evaluation, it is shown that TWDM PON is the most promising option for the future broadband access, where locality-aware P2P video distribution is applied, thanks to its low energy consumption and required switching capacity of the network equipment needed to deliver this service. This conclusion is against the general intuition because of the PON׳s centralized control plane and passive infrastructure without switching capability in the field. Our unexpected conclusion can be of particular interest to operators as it is perfectly aligned with next generation optical access architecture identified by Full Service Access Networks (FSAN).

  • 122.
    Mahloo, Mozhgan
    et al.
    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).
    Dixit, Abhishek
    Lannoo, Bart
    Colle, Didier
    Machuca, Carmen Mas
    Toward Reliable Hybrid WDM/TDM Passive Optical Networks2014In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 52, no 2, S14-S23 p.Article in journal (Refereed)
    Abstract [en]

    Individual users and enterprises are increasingly relying on the access to internet services and cannot accept long interruption time as easily as before. Moreover, the main characteristics of next generation optical access (NGOA) networks, such as long reach and a large number of users per feeder line, turn the network reliability to an important design parameter to offer uninterrupted service delivery. In this regard, protection mechanisms become one of the crucial aspects that need to be considered in the design process of access networks. On the other hand, it should be noted that not all users can afford to pay a high extra cost for protection; hence, it is important to provide resilience in a cost-efficient way. A PON combining WDM and TDM technologies, referred to as hybrid WDM/TDM PON or HPON, is one of the most promising candidates for NGOA networks due to its ability to serve a large number of subscribers and offer high capacity per user. For these reasons, in this article, we propose HPON architecture offering different degrees of resilience depending on the user profiles (i.e., partial and full protection for residential and business access, respectively). Also, the investment cost of providing resilience for the proposed schemes is investigated considering various protection upgrade road maps. Our results confirm that protecting the shared part of network with a large number of users is required in order to keep the failure impact at an acceptable level, with less than 5 percent increase of investment cost compared to the unprotected case. Meanwhile, the proposed end-to-end protection for business users considerably reduces the risk of service interruption for this type of demanding user without a need to duplicate the deployment cost of an unprotected connection. Furthermore, a sensitivity analysis is performed to investigate the impact of changes in business user percentage and protection upgrade time on the deployment cost. The results may be used as advice on cost-efficient deployment of reliable fiber access networks.

  • 123.
    Mahloo, Mozhgan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    dixit, abhishek
    Ghent university-iMind.
    Chen, Jiaji
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mas Machuca, Carmen
    Technical university of Munich(TUM).
    Lannoo, Bart
    Ghent university-iMind.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Towards Reliable Hybrid WDM/TDM Passive Optical NetworksManuscript (preprint) (Other academic)
  • 124.
    Mahloo, Mozhgan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Machuca, Carmen Mas
    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).
    Protection cost evaluation of WDM-based next generation optical access networks2013In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 10, no 1, 89-99 p.Article in journal (Refereed)
    Abstract [en]

    New technologies and advanced network devices make it possible to move towards high capacity access networks able to satisfy the growing traffic demand. Wavelength division multiplexing (WDM) is considered as one of the promising technologies for the next generation access networks since it offers higher bandwidth and longer reach compared to the current technologies (such as time division multiplexing (TDM) based networks). However, the migration to a new technology is typically based on an overall techno-economic study which should assure the network operator that the new implementation is cost effective and profitable while able to provide the required services to the users. Another important aspect in the access network design is the network reliability performance, which can be improved by providing a certain level of protection for equipment and/or infrastructure with high failure impact ratio in order to prevent a big number of the users being affected by a single failure. The cost of protection should be carefully evaluated since providing the backup resources may be too expensive for a network operator. In this paper, we investigate the capital and operational expenditures for two next generation optical access (NGOA) networks based on the WDM technology in dense urban areas. Three scenarios with different splitting ratios are studied for each technology, with and without protection. The aim of this work is to investigate the impact of providing protection on the total cost of NGOA networks. The results show that in the dense urban areas the fibers and digging costs are highly shared among the end users but still vary according to the splitting ratios for different scenarios and the fiber layout. It also can be seen that with a proper fiber layout design, minor extra investment for protection of NGOA networks can make a significant saving on failure related operational cost and that operational expenditures depend significantly on the fiber layout.

  • 125.
    Mahloo, Mozhgan
    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).
    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).
    Cost Modeling of Backhaul for Mobile Networks2014Conference paper (Refereed)
    Abstract [en]

    Wireless heterogeneous networks (HetNets) based on small cells are a cost and energy efficient alternative to provide high capacity to the end users. On the other hand, the cost and energy consumption of backhaul network aggregating data traffic from a large number of base stations may limit the benefits brought by the use of small cell. In HetNet deployments it becomes thus essential to be able to assess the total cost of ownership (TCO) of the backhaul network. This paper presents for the first time a comprehensive cost evaluation methodology to compute the TCO of mobile backhaul networks. The presented model can be instrumental to identify the most critical cost drivers in the backhaul networks and to have a better understanding of the backhaul TCO dynamics when small cells are deployed. The proposed TCO model is then used in a case study where two technology options for the backhaul are considered, i.e., microwave and fiber. The results from the case study show how it is possible to identify the most critical cost factors, thus easing the way towards a cost efficient backhaul design strategy.

  • 126.
    Mahloo, Mozhgan
    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).
    De Souza Farias, Fabricio
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Weyl Albuquerque Costa, João Crisóstomo
    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).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Techno-Economic and Business-Feasibility Modeling of Mobile BackhaulManuscript (preprint) (Other academic)
  • 127.
    Mahloo, Mozhgan
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Chen, J.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Efficient architecture supporting coordinated multipoint transmission in mobile networks2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    High-capacity architecture is proposed aiming to fulfill stringent latency constraint for coordinated multipoint transmission in mobile networks. It offers obviously lower delay, cost and energy consumption as well as better resiliency than the conventional solutions. © 2015 OSA.

  • 128.
    Mahloo, Mozhgan
    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).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Efficient Mobile Backhaul Architecture Supporting Coordinated Multipoint TransmissionManuscript (preprint) (Other academic)
  • 129. Maier, Martin
    et al.
    Chowdhury, Mahfuzulhoq
    Rimal, Bhaskar Prasad
    Van, Dung Pham
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    The Tactile Internet: Vision, Recent Progress, and Open Challenges2016In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 54, no 5, 138-145 p.Article in journal (Refereed)
    Abstract [en]

    The advent of commercially available remote-presence robots may be the precursor of an age of technological convergence, where important tasks of our everyday life will be increasingly done by robots. A very low round-trip latency in conjunction with ultra-high reliability and essentially guaranteed availability for control communications has the potential to move today's mobile broadband experience into the new world of the Tactile Internet for a race with (rather than against) machines. To facilitate a better understanding of the Tactile Internet, this article first elaborates on the commonalities and subtle differences between the Tactile Internet and the Internet of Things and 5G vision. After briefly reviewing its anticipated impact on society and infrastructure requirements, we then provide an up-to-date survey of recent progress and enabling technologies proposed for the Tactile Internet. Given that scaling up research in the area of future wired and wireless access networks will be essential for the Tactile Internet, we pay particular attention to the latency and reliability performance gains of fiber-wireless (FiWi) enhanced LTE-Advanced heterogeneous networks and their role for emerging cloudlets, mobile-edge computing, and cloud robotics. Finally, we conclude by outlining remaining open challenges for the Tactile Internet.

  • 130. Mas Machuca, C.
    et al.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Assessment methodology of protection schemes for next generation optical access networks2015In: Optical fiber technology (Print), ISSN 1068-5200, E-ISSN 1095-9912, Vol. 26, 82-93 p.Article in journal (Refereed)
    Abstract [en]

    Optical access networks are evolving towards next generation solutions offering much higher bandwidth per end point. Moreover, the uninterrupted access to the network services is becoming crucial and therefore operators are now considering protecting their access networks. However, the cost factor is still very important due to the relatively low cost sharing in access segment. For this purpose, this paper proposes an assessment methodology that can be used to compare different protection schemes and help to identify the suitable solution for a given scenario. The assessment criteria includes some reliability measures such as Failure Impact Factor (FIF) and connection availability, as well as cost parameters such as the investment required in greenfield and brownfield scenarios and the increase in power consumption compared to the unprotected network. The proposed criteria have been used to compare 7 representative protection schemes shown in literature, which differ mainly in the number of protected network elements and the technology used for protection (fiber, wireless, etc.). The considered protection schemes have been applied to a hybrid wavelength division multiplexing/time division multiplexing Passive Optical Network (Hybrid PON) architecture in an urban area. It has been shown that it is difficult to identify the absolute best scheme with respect to all the considered criteria. However, depending on the requirements from the operator regarding the targeted reliability performance in the network, an appropriate protection scheme can be recommended for either a greenfield or a brownfield scenario.

  • 131.
    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, 1456-1466 p.Article 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.

  • 132.
    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, 1-6 p.Conference 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.

  • 133.
    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, 1-6 p.Conference paper (Refereed)
  • 134. Mas Machuca, Carmen
    et al.
    Wong, Elaine
    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).
    Energy consumption and reliability performance of survivable hybrid passive optical converged network2016In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2016Conference paper (Refereed)
    Abstract [en]

    The paper provides the methodology to evaluate the tradeoff between the consumed energy, the connection availability and the connection interruption time for survivable hybrid passive optical converged networks in different deployment areas.

  • 135. Mas Machuca, Carmen
    et al.
    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).
    Total cost reduction achieved by offering protection in PON architectures2013In: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 54, no 2, 129-135 p.Article in journal (Refereed)
    Abstract [en]

    Offering protection in access networks has been thought to be significantly expensive. This paper proposes a new way to provide protection in TDM and WDM PONs. It is shown that very low extra investment is needed to provide protection in the case when it is foreseen during network planning. It is also studied how the total cost is reduced due to the significant diminution of the OPEX related to the failure management.

  • 136. Mikac, B.
    et al.
    Dzanko, M.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia .
    Hugues-Salas, E.
    Zervas, G.
    Simeonidou, D.
    Availability aspects of self-healing optical nodes designed by architecture on demand2014In: International Conference on Transparent Optical Networks, 2014Conference paper (Refereed)
    Abstract [en]

    The paper demonstrates the concept of optical networks with nodes implemented by the architecture on demand (AoD) and proposes a procedure for finding out possible benefits of AoD application, related to node and network availability. AoD node structure enables efficient failure management by creating a set of redundant components, which can be used for self-healing of optical nodes after failure. Availability evaluation procedure is based on Monte Carlo simulation of times to failure/repair of network components. A case study network with AoD nodes is compared to the network with hard-wired nodes in regard to availability performance, and results are presented.

  • 137. Mitcsenkov, Attila
    et al.
    Kantor, Miroslaw
    Casier, Koen
    Lannoo, Bart
    Wajda, Krzysztof
    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).
    Geometric versus geographic models for the estimation of an FTTH deployment2013In: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 54, no 2, 113-127 p.Article in journal (Refereed)
    Abstract [en]

    Optical access networks provide a future proof platform for a wide range of services, and today, several operators are deploying fibre to the home (FTTH) networks. Installing an FTTH infrastructure, however, involves very high investment cost. Therefore, a good estimation of the investment cost is important for building a successful business strategy and, consequently, to speed up the FTTH penetration. In this paper, for calculating the amount of cable and fibre in the outside plant together with the associated civil works, and the number of required network elements, two different approaches are investigated: (1) geometric modelling of the fibre plant based on approximate mathematical models and (2) geographic modelling of the fibre plant based on map-based geospatial data. The results obtained from these two approaches can then be used as input for preliminary investment cost calculations and/or techno-economic evaluations. Compared to more complex and accurate geographic modelling, we verify that especially with uneven population density and irregular street system, simple geometric models do not provide accurate results. However, if no geospatial data is available or a fast calculation is desired for a first estimation, geometric models definitely have their relevance. Based on the case studies presented in this paper, we propose some important guidelines to improve the accuracy of the geometric models by eliminating their main distortion factors.

  • 138.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Castoldi, Piero
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Special issue based on selected ONDM 2014 papers2015In: Photonic network communications, ISSN 1387-974X, E-ISSN 1572-8188, Vol. 29, no 3, 227-229 p.Article in journal (Other academic)
  • 139.
    Monti, Paolo
    et al.
    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.
    Cerutti, I.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mohammad, A.
    Velasco, L.
    Wiatr, Pawel
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Green Optical Networks: Power Savings versus Network Performance2015In: Green Communications: Principles, Concepts and Practice, Wiley-Blackwell, 2015, 291-308 p.Chapter in book (Other academic)
    Abstract [en]

    Green optical networks represent a promising solution for reducing the power consumption of telecom networks. For this reason they attract a lot of interest, and several power-aware design and provisioning algorithms are available in the literature. These approaches, however, seem to consider power minimization as their only objective. Little or no attention is given to other important network aspects, for example, delay, connection requests for blocking, quality of the transmitted optical signal, and connection survivability levels. This chapter aims at exploring and evaluating these trade-offs in more detail and to provide a different insight into the green design and provisioning problem in optical networks.

  • 140.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101). 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), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101). KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth. Istanbul Technical University, Turkey.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101). 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), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101). KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fumagalli, Andrea
    The University of Texas at Dallas, US.
    New Dimensions for Survivable Service Provisioning in Optical Backbone and Access Networks2012In: Resilient Optical Network Design: Advances in Fault-Tolerant Methodologists / [ed] Mark Leeson and Yousef Kavian, IGI Global, 2012, 227-252 p.Chapter in book (Refereed)
    Abstract [en]

    Originally, networks were engineered to provide only one type of service, i.e. either voice or data, soonly one level of resiliency was requested. This trend has changed, and today’s approach in serviceprovisioning is quite different. A Service Level Agreement (SLA) stipulated between users and serviceproviders (or network operators) regulates a series of specific requirements, e.g., connection set-up timesand connection availability that has to be met in order to avoid monetary fines. In recent years this hascaused a paradigm shift on how to provision these services. From a “one-solution-fits-all” scenario, wewitness now a more diversified set of approaches where trade-offs among different network parameters(e.g., level of protection vs. cost and/or level of protection vs. blocking probability) play an important role.This chapter aims at presenting a series of network resilient methods that are specifically tailored for adynamic provisioning with such differentiated requirements. Both optical backbone and access networksare considered. In the chapter a number of provisioning scenarios - each one focusing on a specificQuality of Service (QoS) parameter - are considered. First the effect of delay tolerance, defined as theamount of time a connection request can wait before being set up, on blocking probability is investigatedwhen Shared Path Protection is required. Then the problem of how to assign “just-enough” resources tomeet each connection availability requirement is described, and a possible solution via a Shared PathProtection Scheme with Differentiated Reliability is presented. Finally a possible trade off between deploymentcost and level of reliability performance in Passive Optical Networks (PONs) is investigated. 

    The presented results highlight the importance of carefully considering each connection’s QoS parameterswhile devising a resilient provisioning strategy. By doing so the benefits in terms of cost saving andblocking probability improvement becomes relevant, allowing network operators and service providersto maintain satisfied customers at reasonable capital and operational expenditure levels.

  • 141.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Costa, J. C. W. A.
    Farias, F. S.
    Fiorani, M.
    Nilson, Mats
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Västberg, Anders
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Green mobile backhaul in heterogeneous wireless deployments2013In: Asia Communications and Photonics Conference, ACP 2013, Optical Society of America, 2013Conference paper (Refereed)
    Abstract [en]

    This tutorial first introduces and describes different backhaul technological and architectural options (i.e., fiber-, microwave-, and copper-based), then it discusses their impact on the energy consumption of current and future heterogeneous mobile wireless access deployments.

  • 142.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Morea, Annalisa
    Nirmalathas, Ampalavanapillai
    Vokkarane, Vinod M.
    Special issue on energy-efficient optical networks2015In: Photonic network communications, ISSN 1387-974X, E-ISSN 1572-8188, Vol. 30, no 1, 1-3 p.Article in journal (Other academic)
  • 143.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Natalino, Carlos
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ahmed, Jawwad
    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, Renato
    Restoring optical cloud services using relocation2014Conference paper (Refereed)
    Abstract [en]

    Optical cloud is a very popular concept by which storage and computing resources (i.e., IT resources) are distributed over different datacenter (DC) locations interconnected via high-speed optical wavelength division multiplexing (WDM) links. In this paradigm cloud services are provisioned in an anycast fashion, where only the source node needs to be specified in the routing and resource assignment phase, while any DC (with enough IT resources) can be used to accommodate a cloud service. Anycast provisioning has a number of advantages already recognized by optical cloud providers [1][2]. This kind of provisioning paradigm allows, for example, for the live relocation of the already provisioned cloud services, referred to as the service relocation concept. It means that if the DC location is not essential for the execution of a certain cloud service, multiple relocations of the job to other DC locations are possible. This allows for a more efficient management of both the cloud and the transport network resources. Service relocation has also the potential to bring an extra degree of flexibility to survivability strategies. By providing the option for relocating a cloud service it is possible to use a backup path terminating at a DC that is different from the one used by the primary path. This benefit has been assessed in the literature showing the ability to improve resources efficiency by using service relocation in conjunction with path protection strategies [1]. Another instance in which service relocation might be beneficial is when it is combined with restoration-based survivability strategies. These strategies are very efficient in using backup resources, i.e., they are dynamically provisioned only upon a failure, but restoration-based approaches suffer from a certain risk that the backup network resources might not be available when needed [3]. Service relocation can potentially alleviate this problem. This talk presents a study where the objective is to inves- igate if relocating a cloud service disrupted by a network failure is beneficial in terms of both restorability and average connection availability. To this end the talk will present a number of results based on the solution of an efficient and scalable heuristic algorithm able to jointly solve the restoration and service relocation problem. These results are also benchmarked against the performance of an integer linear programming (ILP) model [4] optimizing the same objective function as the heuristic. In summary it can be concluded that by using relocation the average service availability can be significantly improved requiring only a minimal fraction of the cloud services to be relocated. In addition the proposed heuristic behaves very closely to the optimal ILP results in terms of both restorability and average connection availability.

  • 144.
    Monti, Paolo
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    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. KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Mobile backhaul in heterogeneous network deployments: Technology options and power consumption2012In: 14th International Conference on Transparent Optical Networks, 2012, 1-7 p.Conference paper (Refereed)
    Abstract [en]

    Mobile communication networks account for 0.5% of the global energy consumption, a value that is expected to double within the next five years. For this reason, means of reducing the energy consumption in cellular mobile radio networks has recently gained great interest within the research community. In mobile networks the backhaul contribution to the total power consumption is usually neglected because of its limited impact compared to that of the radio base stations. However, meeting the almost exponential increase in mobile data traffic requires a large number of (mainly small) base stations. This means that backhaul networks will take a significant share of the cost and the energy consumption in future systems. Their actual contribution to the energy consumption will depend on the radio base station deployment scenario as well as on the technology and topology choices for the backhaul itself. This paper presents an initial assessment of the power consumption of two established backhaul technologies, i.e., fiber and microwave. For the microwave case, three backhaul topologies are considered, i.e., tree, ring and star, while for the fiber case only one topology is analysed, i.e., a dedicated point-to-point star. The presented results, assuming off-the-shelf products and based on todays network capacity levels, confirm the importance of considering the backhaul when minimizing the total power consumption in heterogeneous network scenarios. They also show the impact of the basic technology and topology choices of the backhaul for minimizing total power consumption.

  • 145. Muhammad, A.
    et al.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia.
    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).
    Forchheimer, R.
    An optimization model for dynamic bulk provisioning in elastic optical networks2014In: Asia Communications and Photonics Conference, ACPC 2014, 2014Conference paper (Refereed)
    Abstract [en]

    We investigate benefits of setup-delay tolerance in elastic optical networks and propose an optimization model for dynamic and concurrent connection provisioning. Simulation shows that the proposed strategy offers significant improvement of the network blocking performance.

  • 146.
    Muhammad, Ajmal
    et al.
    Linköpings tekniska högskola.
    Cavdar, Cicek
    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).
    Fair scheduling of dynamically provisioned WDM connections with differentiated signal quality2012In: 2012 16th International Conference on Optical Networking Design and Modelling, ONDM 2012, IEEE , 2012, 6210281- p.Conference paper (Refereed)
    Abstract [en]

    Emerging, on-demand applications (e.g., Interactive video, ultra-high definition TV, backup storage and grid computing) are gaining momentum and are becoming increasingly important. Given the high bandwidth required by these applications, Wavelength Division Multiplexing (WDM) networks are seen as the natural choice for their transport technology. Among the various on-line strategies proposed to provision such services, the ones based on service level agreement (SLA) metrics such as setup delay tolerance and connection holding-time awareness showed a good potential in improving the overall network blocking performance. However, in a scenario where connection requests are grouped in different service classes, the provisioning success rate might be unbalanced towards those connection requests with less stringent requirements, i.e., not all the connection requests are treated in a fair way. This paper addresses the problem of how to guarantee the signal quality and the fair provisioning of different service classes, where each class corresponds to a specified target of quality of transmission (QoT). With this objective in mind three fair scheduling algorithms are proposed in a dynamic traffic scenario, each one combining in a different way the concept of both set-up delay tolerance and connection holding-time awareness. Proposed solutions are specifically taylored to facilitate the provisioning of the most stringent service class so as to balance the success rate among the different classes. Simulation results confirm that the proposed approaches are able to guarantee a fair treatment reaching up to 99% in terms of Jain's fairness index, considering the per-class success ratio, without compromising the improvements in terms of overall network blocking probability.

  • 147. Muhammad, Ajmal
    et al.
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Forchheimer, Robert
    Service Differentiated Provisioning in Dynamic WDM Networks Based on Set-Up Delay Tolerance2013In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 5, no 11, 1250-1261 p.Article in journal (Refereed)
    Abstract [en]

    Optical networks are expected to provide a unified platform for a diverse set of emerging applications (three-dimensional TV, digital cinema, e-health, grid computing, etc). The service differentiation will be an essential feature of these networks. Considering the fact that users have different levels of patience for different network applications, referred to as set-up delay tolerance, it will be one of the key parameters for service differentiation. Service differentiation based on set-up delay tolerance will not only enable network users to select an appropriate service class (SC) in compliance with their requirements, but will also provide an opportunity to optimize the network resource provisioning by exploiting this information, resulting in an improvement in the overall performance. Improvement in network performance can be further enhanced by exploiting the connection holding-time awareness. However, when multiple classes of service with different set-up delay tolerances are competing for network resources, the connection requests belonging to SCs with higher set-up delay tolerance have better chances to grab the resources and leave less room for the others, resulting in degradation in the blocking performance of less patient customers. This study proposes different scheduling strategies for promoting the requests belonging to smaller set-up delay tolerance SCs, such as giving priority, reserving some fraction of available resources, and augmenting the research space by providing some extra paths. Extensive simulation results show that 1) priority in the rescheduling queue is not always sufficient for eradicating the degradation effect of high delay tolerant SCs on the provisioning rate of the most stringent SC, and 2) by utilizing the proposed strategies, resource efficiency and overall network blocking performance improve significantly in all SCs.

  • 148. Muhammad, Ajmal
    et al.
    Cavdar, Cicek
    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).
    Forchheimer, Robert
    Trading Quality of Transmission for Improved Blocking Performance in All-Optical Networks2013In: IEEE/OSA/SPIE Proceedins, Asia Communications and Photonics Conference, ACP2013, 2013Conference paper (Refereed)
    Abstract [en]

    We propose a connection provisioning strategy in dynamic all-optical networks, which exploit the possibility to allow a tolerable signal quality degradation during a small fraction of holding-time resulting in a significant improvement of blocking performance.

  • 149.
    Muhammad, Ajmal
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    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).
    Joint Optimization of Resource Allocation for Elastic Optical Intra-Datacenter Network2016In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 20, no 9, 1760-1763 p.Article in journal (Refereed)
    Abstract [en]

    The ever-increasing demand for cloud services is posing serious challenges to the scalability of the computing, storing, and networking infrastructure deployed inside the datacenters. To address these challenges, we formulate the integer linear program (ILP) model to minimize the spectrum and the switch port usage by exploiting transparent multi-hop connection capability in elastic optical interconnect architecture for datacenters. The proposed ILP model not only takes into account the networking resources but also the other resources (such as computing and storage) in order to achieve a joint resource optimization in intra-datacenter networks. The optimal results show that substantial savings in both spectrum and switching resources can be achieved by properly tuning the objective function of the proposed optimization strategy.

  • 150. Muhammad, Ajmal
    et al.
    Furdek, Maria
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia .
    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).
    Forchheimer, Robert
    Dynamic provisioning utilizing redundant modules in elastic optical networks based on architecture on demand nodes2014In: Optical Communication (ECOC), 2014 European Conference on, 2014, 1-3 p.Conference paper (Refereed)
    Abstract [en]

    Survivable synthetic ROADMs are equipped with redundant switching modules to support failure recovery. The paper proposes a dynamic connection provisioning strategy which exploits these idle redundant modules to provision regular traffic resulting in a substantial improvement in the blocking performance.

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