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  • 1.
    Abtahi, Farzad
    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, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Khanmohamadi, Sahar
    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).
    Mantelet, G.
    Archambault, E.
    Tremblay, C.
    Bélanger, M. P.
    Optimal Design of Cost- and Energy-Efficient Scalable Passive Optical Backbone Networks2012In: 2012 Asia Communications And Photonics Conference (ACP), 2012, p. AS3D.4-Conference paper (Refereed)
    Abstract [en]

    We propose an optimization model minimizing number of wavelengths in passive optical backbone networks and obtaining the same resource usage as in networks based on active switching while reducing both cost and power consumption.

  • 2.
    Ahmed, Jawwad
    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).
    Chen, Biao
    Department of Optical Engineering, Zhejiang University.
    Mukherjee, Biswanath
    Efficient Inter-Thread Scheduling Scheme for Long-Reach Passive Optical Networks2013In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 51, no 2, p. S35-S43Article in journal (Refereed)
    Abstract [en]

    These days there is a clear trend toward extending the reach of passive optical networks to cover large geographical areas, which enables reduction of the number of central offices and hence has the potential of cost saving in network operation. On the other hand, this reach extension necessitates the design of efficient dynamic bandwidth allocation schemes in order to tackle performance degradation caused by the increased propagation delay in long reach PONs. Among many existing approaches, the multi-thread-based DBA scheme where several bandwidth allocation processes are performed in parallel is considered one of the most effective options to improve network performance in LRPONs. We have found that without proper intercommunication between the overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional single-thread algorithm. With this in mind, this article reviews different inter-thread scheduling schemes for LR-PONs, and proposes a novel approach of integrating the key ideas of the existing ones. Extensive simulation results confirm that our proposed scheme can significantly improve DBA performance for LR-PONs under a variety of scenarios with consideration of different values of network load and reach.

  • 3. Al-Awis, S. N.
    et al.
    Schatz, Richard
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Pang, Xiaodan
    RISE ACREO AB.
    Ozolins, O.
    Jacobsen, Gunnar
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Fotonik och mikrovågsteknik, FMI.
    Popov, Sergei
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Fattah, A. Y.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Phenomenological formula for modelling of physical layer impairments in elastic optical networks2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    An empirical modelling technique is introduced to estimate impact of physical layer impairments in elastic optical networks, which can be used to evaluate transmission quality. The model has been verified experimentally with accuracy beyond (97.3%). © 2015 OSA.

  • 4. Archambault, Emile
    et al.
    Alloune, Nabih
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Xu, Zhenyu
    Tremblay, Christine
    Muhammad, Ajmal
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Littlewood, Paul
    Belanger, Michel
    Routing and spectrum assignment in elastic filterless optical networks2016In: IEEE/ACM Transactions on Networking, ISSN 1063-6692, E-ISSN 1558-2566, Vol. 24, no 6, p. 3578-3592Article in journal (Refereed)
    Abstract [en]

    Elastic optical networking is considered a promising candidate to improve the spectral efficiency of optical networks. One of the most important planning challenges of elastic optical networks is the NP-hard routing and spectrum assignment (RSA) problem. In this paper, we investigate offline RSA in elastic filterless optical networks, which use a passive broadcast-and-select architecture to offer network agility. Here elastic optical network is referred to as the optical network that can adapt the channel bandwidth, data rate, and transmission format for each traffic demand in order to offer maximum throughput. In elastic filterless networks, the presence of unfiltered signals resulting from the drop-and-continue node architecture must be considered as an additional constraint in the RSA problem. In this paper, first the RSA problem in elastic filterless networks is formulated by using integer linear program (ILP) to obtain optimal solutions for small networks. Due to the problem complexity, two efficient RSA heuristics are also proposed to achieve suboptimal solutions for larger networks in reasonable time. Simulation results show that significant bandwidth savings in elastic filterless networks can be achieved compared to the fixed-grid filterless solutions. The proposed approach is further tested in multi-period traffic scenarios and combined with periodical spectrum defragmentation, leading to additional improvement in spectrum utilization of elastic filterless optical networks.

  • 5.
    Cao, Wei
    et al.
    South China Normal Univ, Ctr Opt & Electromagnet Res, South China Acad Adv Optoelect, Guangzhou, Guangdong, Peoples R China..
    Song, Wenxu
    South China Normal Univ, Ctr Opt & Electromagnet Res, South China Acad Adv Optoelect, Guangzhou, Guangdong, Peoples R China..
    Li, Xinge
    South China Normal Univ, Sch Psychol, Guangzhou, Guangdong, Peoples R China..
    Zheng, Sixiao
    Fudan Univ, Acad Engn & Technol, Shanghai, Peoples R China..
    Zhang, Ge
    Caihongqiao Children Rehabil & Serv Ctr Panyu Dis, Guangzhou, Guangdong, Peoples R China..
    Wu, Yanting
    South China Normal Univ, Sch Psychol, Guangzhou, Guangdong, Peoples R China..
    He, Sailing
    South China Normal Univ, Ctr Opt & Electromagnet Res, South China Acad Adv Optoelect, Guangzhou, Guangdong, Peoples R China..
    Zhu, Huilin
    Sun Yat Sen Univ, Child Dev & Behav Ctr, Affiliated Hosp 3, Guangzhou, Guangdong, Peoples R China..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Interaction With Social Robots: Improving Gaze Toward Face but Not Necessarily Joint Attention in Children With Autism Spectrum Disorder2019In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 10, article id 1503Article in journal (Refereed)
    Abstract [en]

    It is widely recognized that robot-based interventions for autism spectrum disorders (ASD) hold promise, but the question remains as to whether social humanoid robots could facilitate joint attention performance in children with ASD. In this study, responsive joint attention was measured under two conditions in which different agents, a human and a robot, initiated joint attention via video. The participants were 15 children with ASD (mean age: 4.96 +/- 1.10 years) and 15 typically developing (TD) children (mean age: 4.53 +/- 0.90 years). In addition to analyses of fixation time and gaze transitions, a longest common subsequence approach (LCS) was employed to compare participants' eye movements to a predefined logical reference sequence. The fixation of TD toward agent's face was earlier and longer than children with ASD. Moreover, TD showed a greater number of gaze transitions between agent's face and target, and higher LCS scores than children with ASD. Both groups showed more interests in the robot's face, but the robot induced a lower proportion of fixation time on the target. Meanwhile participants showed similar gaze transitions and LCS results in both conditions, suggesting that they could follow the logic of the joint attention task induced by the robot as well as human. We have discussed the implications for the effects and applications of social humanoid robots in joint attention interventions.

  • 6.
    Cao, Yuan
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Zhao, Yongli
    Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China..
    Lin, Rui
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yu, Xiaosong
    Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China..
    Zhang, Jie
    Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, Beijing 100876, Peoples R China..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Multi-tenant secret-key assignment over quantum key distribution networks2019In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 27, no 3, p. 2544-2561Article in journal (Refereed)
    Abstract [en]

    Quantum key distribution (QKD) networks are promising to progress towards widespread practical deployment over existing fiber infrastructures in the near future. Given the high cost and difficulty of deploying QKD networks, multi-tenancy becomes promising to improve cost efficiency for future QKD networks. In a multi-tenant QKD network, multiple QKD tenants can sham the same QKD network infrastructure to obtain secret keys for securing their data transfer. Since the secret-key resources are finite and precious in QKD networks, how to achieve efficient multi-tenant secret-key assignment (MTKA) to satisfy the secret-key demands of multiple QKD tenants over QKD networks becomes a significant problem. In this regard, this study addresses the MTKA problem over QKD networks. A new multi-tenant QKD network architecture is proposed based on software defined networking (SDN) and quantum key pool (QKP) techniques. A secret-key rate sharing scheme is presented and a heuristic algorithm is designed to implement efficient MTKA over QKD networks. A new performance metric, namely matching degree (MD) that reflects the balance between QKD network secret-key resources and QKD tenant requests, is defined and evaluated. Simulation studies indicate that high QKD tenant requests accommodation and efficient secret-key resource usage can be achieved via maximizing the value of MD. 

  • 7. Cen, M.
    et al.
    Chen, J.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moeyaert, V.
    Mégret, P.
    Wuilpart, M.
    A full monitoring scheme for long-reach TWDM PONs2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    We propose a simple system that realizes for the first time full monitoring functionality for long-reach PON. Theoretical analysis and experimental validation demonstrate the proposed scheme is capable of providing accurate fault localization. © 2015 OSA.

  • 8. Cen, M.
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moeyaert, V.
    Megret, P.
    Wuilpart, M.
    Advanced Transmission-Reflection-Analysis (TRA) system for Long-Reach Passive Optical Network monitoring2015In: International Conference on Transparent Optical Networks, IEEE Computer Society, 2015, Vol. 2015, article id 7193394Conference paper (Refereed)
    Abstract [en]

    Long-Reach Passive Optical Networks (LR-PONs) allows for extending the distance between the central office (CO) and end users from a few kilometers to several tens of kilometers and beyond. It in turn reduces the number of active equipment in the field, bringing potentially cost saving. However, due to its high capacity and large coverage, LR-PON becomes increasingly vulnerable to various failures. Therefore, network monitoring becomes extremely important to guarantee an appropriate level of network reliability and performance. In this paper, we report on an advanced LR-PON monitoring solution that can supervise the whole LR-PON ring section in a cost-effective manner. Instead of using the conventional optical time domain reflectometry (OTDR) approach, we implement multi wavelength Transmission-Reflection Analysis (nλ-TRA) as the monitoring technique. The TRA approach is based on the unique relationship between the optical powers transmitted and backscattered by the fiber for a given loss location. Since TRA only requires measuring the power levels of monitoring signals, it outperforms other conventional methods thanks to its superior detection speed and a simple system configuration. Both experimental results have demonstrated that the proposed system can reach high accuracy for fault localization.

  • 9. Cen, M.
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Moeyaert, V.
    Megret, P.
    Wuilpart, M.
    Full monitoring for Long-Reach TWDM Passive Optical Networks based on TRA technique2016In: International Conference on Transparent Optical Networks, IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

    Long-Reach Passive Optical Networks (LR-PONs) consolidates of metropolitan and access networks by extending the distance between the Central Office (CO) and the end users, which in turn simplifies the network and potentially brings cost savings. With the explosively growing of data traffic, Time and Wavelength Division Multiplexing (TWDM) technology have also been employed in LR-PON to realize high capacity. However, due to high capacity and large coverage, the presence of a single failure may cause a huge loss of data and affect a large number of subscribers in LR-PON. Efficient network fault monitoring therefore becomes a key to improve the level of network reliability. In this paper, we report an advanced solution realizing fault detection, identification and localization in both feeder and distribution fiber segments of TWDM LR-PON. Instead of using the conventional optical time domain reflectometry (OTDR) approach, we implement multi wavelength Transmission-Reflection Analysis (nλ-TRA) as the monitoring technique, which is able to provide a good spatial accuracy and a high detection speed without interfering with the data traffic. Theoretical analysis and experimental validation demonstrate that the proposed scheme is capable of providing an accurate fault monitoring functionality.

  • 10. Cen, M.
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Moeyaert, V.
    Mégret, P.
    Wuilpart, M.
    Efficient monitoring for ring-based long-reach passive optical networks2015In: Optical Fiber Communication Conference, OFC 2015, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    An efficient monitoring scheme based on transmission-reflection analysis is proposed for long-reach passive optical networks. Both experimental simulation results have demonstrated that the proposed scheme provides better localization functionality than the conventional methods.

  • 11. Cen, M.
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mégret, P.
    Moeyaert, V.
    Wuilpart, M.
    Fast and simple fault monitoring for long-reach passive optical networks2014In: 2014 European Conference on Optical Communication, (ECOC), IEEE , 2014, p. 6964070-Conference paper (Refereed)
    Abstract [en]

    We propose a fast and simple monitoring system based on multi-wavelength bi-directional transmission reflection analysis approach for long-reach passive optical networks. Both experimental and simulation results have demonstrated the proposed system can reach high accuracy for fault localization.

  • 12. Cen, Min
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moeyaert, Veronique
    Megret, Patrice
    Wuilpart, Marc
    Advanced Fault-Monitoring Scheme for Ring-Based Long-Reach Optical Access Networks2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 10, p. 1876-1886Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel fiber fault-monitoring system for long-reach optical access networks based on a transmission-reflection analysis approach. By launching an un-modulated continuous-wave optical signal into the feeder ring and measuring the transmitted and reflected/backscattered optical powers, the proposed monitoring scheme is able to detect, identify, and localize any major fault (covering both reflective and nonreflective events) with a good spatial accuracy (<= 10 m) and a high detection speed (3 s). Both experimental and simulation results have demonstrated that the proposed system provides fiber monitoring functionality better than that obtained by the conventional methods.

  • 13. Cen, Min
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). South China Normal University, China.
    Moeyaert, Veronique
    Megret, Patrice
    Wuilpart, Marc
    Full monitoring for long-reach TWDM passive optical networks2016In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 24, no 14, p. 15782-15797Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel and simple fiber monitoring system based on multi-wavelength transmission-reflection analysis for long-reach time and wavelength division multiplexing passive optical networks. For the first time, the full localization functionality of long-reach passive optical networks is possible with the proposed monitoring scheme, including supporting fault detection, identification, and localization in both feeder and distribution fiber segments. By measuring the transmitted and reflected/backscattered optical powers launched by an unmodulated continuous-wave optical source, the proposed solution is able to supervise the network with good spatial accuracy, a high detection speed and a low impact on data traffic. Both the theoretical analysis and experimental validation show that the proposed scheme is capable of providing an accurate fault monitoring functionality for long-reach time and wavelength division multiplexing passive optical networks.

  • 14. Cen, Min
    et al.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Moeyaert, Veronique
    Megret, Patrice
    Wuilpart, Marc
    Multi-wavelength transmission-reflection analysis for fiber monitoring2014In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 22, no 25, p. 31248-31262Article in journal (Refereed)
    Abstract [en]

    We propose and implement a novel approach based on multi-wavelength Transmission-Reflection Analysis (MW-TRA) technique for monitoring lossy events (e.g. disconnected connectors, fiber breaks and fiber bendings) along an optical fiber link. By launching un-modulated continuous-wave lights carried by different wavelengths into the fiber and measuring their transmitted and reflected/backscattered optical powers, our proposed MW-TRA scheme is able to localize any lossy event (including both reflective and non-reflective) and to quantify the corresponding insertion and return losses with high accuracy.

  • 15.
    Chen, Biao
    et al.
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications, Zhejiang University, Hangzhou 310027, China.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Efficient and fine scheduling algorithm for bandwidth allocation in Ethernet passive optical networks2006In: IEEE Journal of Selected Topics in Quantum Electronics, ISSN 1077-260X, E-ISSN 1558-4542, Vol. 12, no 4, p. 653-660Article in journal (Refereed)
    Abstract [en]

    A novel fine scheduling algorithm is introduced for upstream bandwidth allocation in an Ethernet-based passive optical network. This scheduling algorithm consists of an inter optical network unit (ONU) scheduler at the optical line terminal (OLT) and an intra-ONU scheduler at each ONU. In the inter-ONU scheduling, a novel GATE/REPORT approach is introduced to eliminate the unused remainders without transmission delay and maximize the utilization of bandwidth. Our novel intra-ONU scheduler gives fair bandwidth allocation to the queues of different priorities for each user in a hierarchical and decentralized way. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user..

  • 16. Chen, Biao
    et al.
    Guo, Changjian
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Zhang, Linjian
    Jiang, Qiong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Add/drop multiplexing and TDM signal transmission in an optical CDMA ring network2007In: Journal of Optical Networking, ISSN 1536-5379, Vol. 6, no 8, p. 969-974Article in journal (Refereed)
  • 17.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Design, analysis and simultion for optical access and wide-area networks.2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to the tremendous growth of traffic volume caused by both exponential increase of number of Internet users and continual emergence of new bandwidth demanding applications, high capacity networks are required in order to satisfactorily handle the extremely large amount of traffic. Hence, optical fiber communication is the key technology for the network infrastructure. This thesis addresses design, analysis and simulation of access and core networks targeting important research problems, which need to be tackled for the effective realization of next generation optical networks.

    Among different fiber access architectures, passive optical network (PON) is considered as the most promising alternative for the last mile connection due to its relatively low cost and resource efficiency. The inherent bursty nature of the user generated traffic results in dynamically changing bandwidth demand on per subscriber basis. In addition, access networks are required to support differentiated quality of service and accommodate multiple service providers. To address these problems we proposed three novel scheduling algorithms to efficiently realize dynamic bandwidth allocation in PON, along with guaranteeing both the priority and fairness of the differentiated services among multiple users and/or service providers. Meanwhile, because of the increasing significance of reliable access to network services, an efficient fault management mechanism needs to be provided in PON. In addition, access networks are very cost sensitive and the cost of protection should be kept as low as possible. Therefore, we proposed three novel cost-effective protection architectures keeping in mind that reliability requirement in access networks should be satisfied at the minimal cost.

    Regarding the optical core networks, replacing electronic routers with all-optical switching nodes can offer significant advantages in realizing high capacity networks. Because of the technological limitations for realizing all-optical nodes, the focus is put on the ingenious architecture design. Therefore, we contributed on novel switching node architectures for optical circuit and packet switching networks. Furthermore, we addressed different aspects of routing and wavelength assignment (RWA) problem, which is an important and hard task to be solved in wavelength routed networks. First, we proposed an approach based on the information summary protocol to reduce the large amount of control overhead needed for dissemination of the link state information in the case of adaptive routing. In addition, transparency in optical networks may cause vulnerability to physical layer attacks. To target this critical security related issue, we proposed an RWA solution to minimize the possible reachability of a jamming attack.

    Finally, in order to evaluate our ideas we developed two tailor-made simulators based on discrete event driven system for the detailed studies of PON and switched optical networks. Moreover, the proposed tabu search heuristic for our RWA solution was implemented in C++.

  • 18.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Efficient resiliency mechanisms for next generation passive optical networks2013In: ICICS 2013 - Conference Guide of the 9th International Conference on Information, Communications and Signal Processing, IEEE Computer Society, 2013, p. 6782903-Conference paper (Refereed)
    Abstract [en]

    Future broadband access networks are expected to cover large service areas while fulfilling high bandwidth request on a per-user basis. The rapidly increasing traffic demand is also driven by the growing popularity of mobile data services, which is placing high-capacity requirement on the backhaul. Due to advances in wavelength division multiplexing (WDM) technology, WDM based architectures have been considered as promising candidates for next generation optical access, such as WDM passive optical network (PON), and hybrid WDM/time division multiplexing (TDM) PON. Meanwhile, resilience technique will play a more prominent role in emerging access networks due to their significantly increased capacity and coverage compared to the current deployments. Therefore, efficient resiliency mechanisms are highly required to enable uninterrupted network operation where a certain level of reliability performance can be guaranteed. In this work, we first evaluate reliability performance of each segment of next generation optical access networks and then identify the most important part for protection. A particular attention is paid to the reduction of failure impact.

  • 19.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Chen, Bao
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    A Novel Joint Scheduling Algorithm for Multiple Services in 10G EPON2008In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 7137Article in journal (Other academic)
    Abstract [en]

    In this paper, we propose and evaluate a novel joint scheduling algorithm for multiple services which can support differentiated services and bandwidth allocation with global priority of different traffic such as Triple-play: voice, video and Internet services. Simulation results show that for the higher priority traffic better delay and jitter performance can be achieved compared with the lower priority traffic.

  • 20.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Biao
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    A novel algorithm for intra-ONU bandwidth allocation in ethernet passive optical networks2005In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 9, no 9, p. 850-852Article in journal (Refereed)
    Abstract [en]

    A novel decentralized algorithm is introduced for the intra-ONU bandwidth allocation in an Ethernet Passive Optical Network (EPON). The algorithm is of low computational complexity, and can guarantee both the priority and fairness of the differentiated services. Simulation results are presented and compared with those of two existing bandwidth allocation algorithms.

  • 21.
    Chen, Jiajia
    et al.
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications of Zhejiang University, Zhejiang University.
    Chen, Biao
    Centre for Optical and Electromagnetic Research, Joint Laboratory of Optical Communications of Zhejiang University, Zhejiang University.
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Optics.
    A novel hierarchical algorithm for intra-ONU scheduling in an ethernet passive optical network2005In: Network Architectures, Management, and Applications III, 2005, Vol. 6022, p. W220-W220Conference paper (Refereed)
    Abstract [en]

    The quality of service (QoS) requirements of end users and services are totally different, and thus the multi-oriented (user-oriented and service-oriented) scheduling for access networks based on a remote scheduling system especially for EPONs is desired to replace the single-oriented (user-oriented or service-oriented) scheduling. In this paper we introduce a novel hierarchical algorithm of intra-ONU scheduling for multi-oriented QoS, which can guarantee both the priority of the differentiated services and the fairness of the different users. Numerical results have shown that our overall scheduling algorithm can fulfill various requirements of delay and throughput for the transmission of multimedia traffic for each end user.

  • 22.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Biao
    Centre for Optical Electromagnetic Research, Joint Laboratory of Optical Communications, Zhejiang University, Hangzhou 310027, China.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
    Self-protection scheme against failures of distributed fiber links in an Ethernet passive optical network2006In: Journal of Optical Networking, ISSN 1536-5379, Vol. 5, no 9, p. 662-666Article in journal (Refereed)
    Abstract [en]

    A novel self-protection scheme for an Ethernet passive optical network is introduced and studied at both the physical and the media access control layers. The scheme is simple and fast and can provide 1: 1 protection and automatic traffic restoration against the fiber link failure between a remote node ( RN) and any optical network unit (ONU). Simulation results show that fiber failure does not degrade the transmission performance, and the restoration time depends mainly on the switch time of the physical layer. Our protection scheme saves many long fibers, does not influence other normal ONUs, and requires no active device in the RN.

  • 23.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Biao
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Joint Bandwidth Scheduling to Support Differentiated Services and Multiple Service Providers in 1G and 10G EPONs2009In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, ISSN 1943-0620, Vol. 1, no 4, p. 343-351Article in journal (Refereed)
    Abstract [en]

    Dynamic bandwidth allocation (DBA) is one of the key issues for the current (1G) and next-generation (10G) Ethernet-based passive optical network (EPON) systems. We present a novel bandwidth scheduling scheme that integrates specific scheduling implementations in the optical line terminal and optical network units. This scheduling enables multiservice access with scalable quality of service support for the triple-play (video, voice, and data) services and open access. Our simulation results show that the proposed scheduling algorithm performs very well in supporting service differentiation and fair allocation of bandwidth to different service providers. A performance comparison between 1G and 10G systems is also presented. To the best of our knowledge, no detailed study of DBA in a 10G EPON can be found in the literature so far.

  • 24.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    De Andrade, M.
    Skubic, Björn
    Ericsson Research.
    Ahmed, Jawwad
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Enhancing IPACT with limited service for multi-thread DBA in long-reach EPON2010In: Communications and Photonics Conference and Exhibition (ACP), 2010 Asia, 2010, p. 629-630Conference paper (Refereed)
    Abstract [en]

    In this paper we propose an enhanced IPACT with limited service for multi-thread DBA in long-reach EPON. We evaluate our scheme by simulations in single-thread and double-thread cases and show that the DBA performance in terms of average delay and jitter can be significantly improved by the proposed algorithm.

  • 25.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Gong, Yu
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    High Capacity and Energy Efficient Optical Interconnects at Top of the Rack in Datacentres2014Conference paper (Refereed)
  • 26.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Gong, Yu
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Aleksic, Slavisa
    Optical Interconnects at the Top of the Rack for Energy-Efficient Data Centers2015In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 53, no 8, p. 140-148Article in journal (Refereed)
    Abstract [en]

    The growing popularity of cloud and multimedia services is dramatically increasing the traffic volume that each data center needs to handle. This is driving the demand for highly scalable, flexible, and energy-efficient networks inside data centers, in particular for the edge tier, which requires a large number of interconnects and consumes the dominant part of the overall power. Optical fiber communication is widely recognized as the highest energy-and cost-efficient technique to offer ultra-large capacity for telecommunication networks. It has also been considered as a promising transmission technology for future data center applications. Taking into account the characteristics of the traffic generated by the servers, such as locality, multi-cast, dynamicity, and burstiness, the emphasis of the research on data center networks has to be put on architectures that leverage optical transport to the greatest possible extent. However, no feasible solution based on optical switching is available so far for handling the data center traffic at the edge tier. Therefore, apart from conventional optical switching, we investigate a completely different paradigm, passive optical interconnects, and aim to explore the possibility for optical interconnects at the top of the rack. In this article, we present three major types of passive optical interconnects and carry out a performance assessment with respect to the ability to host data center traffic, scalability, optical power budget, complexity of the required interface, cost, and energy consumption. Our results have verified that the investigated passive optical interconnects can achieve a significant reduction of power consumption and maintain cost at a similar level compared to its electronic counterpart. Furthermore, several research directions on passive optical interconnects have been pointed out for future green data centers.

  • 27.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Novel Node Architectures for Wavelength-Routed WDM Networks with Wavelength Conversion Capability2008In: 34th European Conference and Exhibition on Optical Communication ECOC’08, 2008, 2008Conference paper (Other academic)
    Abstract [en]

    We present and evaluate two novel node architectures based on optical switch matrices and wavelength converters (WCs). Relatively small and cheap switches are required while WCs efficiently improve blocking probability

  • 28.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Kantor, Miroslaw
    Wajda, Krzysztof
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Network Protection2008In: Next-Generation FTTH Passive Optical Networks: Research towards unlimited bandwidth access / [ed] Josep Prat, Springer, 2008, p. 111-124Chapter in book (Refereed)
    Abstract [en]

    The significance of broadband and multimedia telecommunications is still increasing and the use of fibre-optic technology in the access network is growing very fast in order to meet customers demand. Along with the higher bandwidth demand, increasing number of subscribers, and advances in the Wavelength Division Multiplexing (WDM) device technology, the WDM Passive Optical Network (PON) and hybrid WDM/TDM (Time Division Multiplexed) PON has been considered as a next generation solution for the broadband access. Meanwhile, in order to meet Service Level Agreement (SLA) and guarantee the appropriate level of connection availability, fault management within any type of the PONs becomes more significant for the reliable service delivery and business continuance. Connection availability is an issue of deep concern to network operators since failure of any access network component, and thus interruption of their services, could result in significant losses of revenue. This chapter reviews some protection schemes in PONs and provides reliability performance evaluation for the considered architectures. A customer typically expects the end-to-end service availability at least at the same level as that provided by the traditional copper based systems. Thus, before investing in a new technology network operators need to make sure that it will not degrade the service quality perceived by the customers. To avoid misunderstanding we provide the set of definitions used in this chapter. Next, we review the protection schemes in PONs and follow with the reliability analysis and performance evaluation. Finally, we draw some conclusions.

  • 29.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Khanmohamadi, Sahar
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Abtahi, Farzad
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Xu, Zhenyu
    Cassidy, Andrew
    Tremblay, Christine
    Littlewood, Paul
    Asselin, Serge
    Belanger, Michel P.
    Passive wide area network solutions: Filterless and semi-filterless optical networks2011In: 13th International Conference on Transparent Optical Networks (ICTON) / [ed] Jaworski, M; Marciniak, M, 2011Conference paper (Refereed)
    Abstract [en]

    Advances in optical coherent transmission and electrical compensation technologies (such as coherent receiver and forward error correction FEC) have stimulated ideas for novel optical network architectures. Recently proposed passive wide area network solution, referred to as filterless optical network [1 #x2013;2] eliminates or minimizes the usage of active photonic reconfigurable network elements. In this approach, only the passive splitters and combiners for interconnecting the fiber links are utilized, which makes this network architecture more cost- and energy-effective as well as more reliable compared with networks based on active optical switching. However, the filterless optical network architecture implies some constraints on fiber interconnection design, maximum fiber-tree length and wavelength reuse due to its broadcast nature. Consequently, filterless solution always requires more resources (i.e. number of wavelengths) compared with the active switched optical networks which are allowed to utilize reconfigurable and coloured components. In order to improve the wavelength utilization while maintaining flexibility of resource allocation, this work extends the idea of filterless optical network by introducing some passive coloured components (e.g., fiber Bragg grating FBG, red/blue filters, etc) to drop local signals at some determined nodes. This approach is referred to as semi-filterless optical network. Furthermore, the semi-filterless solution maintains the passive feature, enabling high reliability and efficiency of cost and energy. Meanwhile, its non-broadcast property at some determined nodes has potential to decrease the transmission impairments and hence relax the constraints on fiber interconnection design and the maximal transparent length, which are strict in the filterless optical network. Our preliminary results confirm the advantages of semi-filterless solution.

  • 30.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Li, Jun
    KTH.
    Efficient Mobile Backhaul Architecture Offering Ultra-Short Latency for Handovers2016In: 2016 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), IEEE, 2016Conference paper (Refereed)
  • 31.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Lu, Xiang
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Analytical Formulas for Calculating the Blocking Probability of a Dynamic Star Network2005In: Chinese Optics Letters, ISSN 1671-7694, Vol. 3, no 10, p. 579-582Article in journal (Refereed)
    Abstract [en]

    For a dynamic routing and wavelength assignment (RWA) a star topology is shown to be more efficient in comparison with a ring topology. Analytical formulas for a dynamic RWA in a star network are presented and verified with virtual simulation.

  • 32.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Mahloo, Mozhgan
    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).
    Reducing the Impact of Failures in Next Generation Optical Access Networks2012In: 2012 Asia Communications And Photonics Conference (ACP), 2012, p. AS1D.2-Conference paper (Refereed)
    Abstract [en]

    Reliability performance of next generation optical access (NGOA) networks offering high bandwidth and large service coverage is evaluated. A particular attention is paid to the reduction of the impact of failures in NGOA.

  • 33.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Poudel, Sunil
    KTH, School of Information and Communication Technology (ICT).
    Urban, Patryk
    Fault monitoring for multi-operator and multi-service WDM PON2013In: Asia Communications and Photonics Conference, ACP 2013, Optical Society of America, 2013Conference paper (Refereed)
    Abstract [en]

    We propose fault supervision mechanisms for open WDM PON, where multiple operators could co-exist and deliver different services on a common fibre plant. The feasibility of such schemes has been validated by evaluating transmission performance.

  • 34.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Urban, P.
    Garcia, J. M.
    Cost-efficient fault supervision schemes for next generation optical access networks (invited)2014In: Asia Communications and Photonics Conference, ACP, 2014Conference paper (Refereed)
    Abstract [en]

    This paper presents different ways to implement fault monitoring technique for next generation optical access networks. A performance comparison is carried out to identify the most cost-efficient fault supervision schemes.

  • 35.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Urban, Patryk J.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Fast fault monitoring technique for reliable WDM PON: Achieving significant operational saving2013In: 2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013, IEEE , 2013, p. 6532499-Conference paper (Refereed)
    Abstract [en]

    We propose a fast fault supervision technique compatible with an efficient resilience scheme for WDM PON. Several drop fibres can be monitored simultaneously so that a significant reduction of operational cost can be achieved.

  • 36.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Advances in Fiber Access Networks Development: Efficient Resource Allocation and Cost Effective Protection2011In: BROADBAND ACCESS COMMUNICATION TECHNOLOGIES V / [ed] Dingel, B; Jain, R; Tsukamoto, K, 2011, Vol. 7958, p. 795808-1-795808-10Conference paper (Refereed)
    Abstract [en]

    Access networks based on optical fiber can easily fulfill high bandwidth demand and cover large service areas. Fiber access networks are also scalable to meet the future capacity request. Among several alternatives, passive optical network (PON)is considered as the most promising one, because its passive point-to-multipoint architecture is characterized by relatively low deployment and operational cost. On the other hand, the passive point-to-multipoint feature in PONs also creates a number of challenges, such as efficient resource allocation and cost-effective protection. This paper provides an overview of the advances related to these two issues and points out the research topics that are still open and need to be investigated.

  • 37.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Analysis of protection schemes in PON compatible with smooth migration from TDM-PON to hybrid WDM/TDM-PON2007In: Journal of Optical Networking, ISSN 1536-5379, Vol. 6, no 5, p. 514-526Article in journal (Refereed)
    Abstract [en]

    We propose what we believe to be a novel protection scheme compatible with smooth migration from a time-division multiplexing (TDM) passive optical network (PON) to a WDM/TDM-PON. We show that our scheme is very cost effective while keeping connection availability, recovery time, and power budget at an acceptable level. We focus on the protection schemes, overview the existing methods, and introduce a link protection scheme compatible with smooth migration from TDM-PON to hybrid WDM/ TDM-PON. Furthermore, we analyze the cost, connection availability, recovery time, and optical link budget for different protection schemes in order to find the cost-effective solution both for the TDM-PON and hybrid WDM/ TDM- PON. (c) 2007 Optical Society of America.

  • 38.
    Chen, Jiajia
    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.
    Efficient Next-Generation Optical Networks: Design and Analysis of Fiber Access and Core Networks2010Book (Refereed)
    Abstract [en]

    Due to the tremendous growth of traffic volume caused by both exponential increase of number of Internet users and continual emergence of new bandwidth demanding applications, high capacity networks are required in order to satisfactorily handle the extremely large amount of traffic. Hence, optical fiber communication is the key technology for the network infrastructure. This book addresses design and analysis of access and core networks targeting important research problems, which need to be tackled for the effective realization of next-generation optical networks. We hope that this book will give the researchers and engineers who work on optical networks an overview of the current trends and contribute to a deeper understanding of problems related to next-generation optical access and wide-area networks, which have tremendous potential to increase network capacity and support the rapidly growing bandwidth demand.

  • 39.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Communication Systems, CoS (closed 2012-01-01).
    Improvements in optical communications networks2009Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    An optical communications network ( 10) comprising an optical line termination ( 12), and a first optical multiplexer/demultiplexer (MUX/DEMUX) ( 14), comprising N input ports and N output ports. The network (10) further comprises a plurality of wavelength division multiplexed passive optical network (WDM PON) distribution networks (22) coupled to a respective one of the MUX/DEMUX output ports and comprising optical network units (20). Feeder fibres ( 16) are coupled between the optical line termination and a respective one of the MUX/DEMUX input ports. Interconnection fibres ( 18) are coupled between respective pairs of the optical network units.

  • 40.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Performance Analysis of Protection Schemes Compatible with Smooth Migration from TDM-PON to Hybrid WDM/TDM-PON2007In: OFC/NFOEC 2007 - Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007, 2007Conference paper (Refereed)
    Abstract [en]

    We propose a novel protection scheme compatible with smooth migration from TDM-PON to WDM/TDM-PON. We show that our scheme is very cost-effective while keeping connection availability, recovery time and power budget at the acceptable level.

  • 41.
    Chen, Jiajia
    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.
    Reliable overlaid PON architecture using WDM with shared protection2010In: Optical Communication (ECOC), 2010 36th European Conference and Exhibition on, 2010, p. 1-3Conference paper (Refereed)
    Abstract [en]

    A novel shared protection scheme using WDM in overlaid PONs is presented and evaluated. A large number of users can be supported and connection availability higher than 99.999% can be offered at a minimum cost.

  • 42.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chughtai, Mohsan Niaz
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Forzati, Marco
    Scalable Passive Optical Network Architecture for Reliable Service Delivery2011In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 3, no 9, p. 667-673Article in journal (Refereed)
    Abstract [en]

    A scalable and reliable architecture for both a wavelength division multiplexing passive optical network and a hybrid wavelength and time division multiplexing passive optical network with self-healing capability is presented and evaluated. Our protection scheme is compatible with a cascaded arrayed waveguide grating that can accommodate an ultra-large number of end users. A simple interconnection pattern between two adjacent optical network units (ONUs) is applied in order to provide protection for distributed fibers between a remote node and the ONUs. Therefore, the investment cost on a per-user basis can be significantly reduced. Meanwhile, the performance evaluation shows that our approach can achieve high connection availability while maintaining the support of long reach and high splitting ratio.

  • 43.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    A novel protection scheme for a hybrid WDM/TDM PON2007In: NETWORK ARCHITECTURES, MANAGEMENT, AND APPLICATIONS V, 2007, Vol. 6784, p. F7840-F7840Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel protection scheme based on the cyclic property of an array waveguide grating (AWG) and neighboring connection pattern between two adjacent optical network units (ONUs) for the hybrid WDM/TDM passive optical networks (PONs). Our scheme uses 50% fewer wavelengths while offering one order of magnitude better connection availability than the existing scheme.

  • 44.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    High utilization of wavelengths and simple interconnection between users in a protection scheme for passive optical networks2008In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 20, no 5-8, p. 389-391Article in journal (Refereed)
    Abstract [en]

    A novel protection architecture for passive optical networks (PONs) is presented and evaluated. It is based on the cyclic property of arrayed waveguide gratings (AWGs) and the interconnection between two adjacent optical network units. The proposed scheme is compatible with both wavelength-division-multiplexing (WDM) PONs and hybrid WDM/time-division-multiplexing PONs. It is compared with two existing schemes and shown to have several advantages: 1) 50% less wavelengths is needed; 2) the fiber interconnections are simplified; 3) the connection availability is improved by one order of magnitude.

  • 45.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    He, Sailing
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Novel Architectures of Asynchronous Optical Packet Switch2007In: 33rd European Conference and Exhibition on Optical Communication ECOC’07, 2007, IEEE conference proceedings, 2007Conference paper (Other academic)
    Abstract [en]

    We propose two asynchronous optical packet switch architectures, with efficient contention resolution based on controllable optical buffers and tunable wavelength converters TWCs. Providing a few shared optical buffers significantly boosts the performance obtained by TWCs.

  • 46.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Kantor, M.
    Thylén, Lars
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Comparison of hybrid WDM/TDM passive optical networks (PONs) with protection2008In: 34th European Conference on Optical Communication, 2008, ECOC 2008, 2008Conference paper (Refereed)
    Abstract [en]

    We present the evolution of PON protection and compare reliability performance related to investment and management cost for some representative cases. Our results can indicate the most cost efficient architectures.

  • 47.
    Chen, Jiajia
    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.
    Machuca, C.
    Jaeger, M.
    Cost vs. reliability performance study of fiber access network architectures2010In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 48, no 2, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Fiber to the home is the future-proof technology for broadband access networks. Several fiber access network architectures have been developed (e.g., point-to-point, active optical network, and passive optical network). PON is considered the most promising solution due to the relatively low deployment cost and high resource efficiency. Meanwhile, because of the growing demand for reliable service delivery, fault management is becoming more significant in all parts of communications networks. However, there is a trade-off between the cost of protection and the level of service reliability. Since economical aspects are most critical in the access part of networks, improving reliability performance by duplication of network resources (and capital expenditures) could be too expensive. Therefore, recent work has focused on PON protection schemes with reduced CAPEX. The future trend will probably migrate toward minimizing operational expenditures during the access network lifetime. The main contributions of this article include providing a general method for CAPEX and OPEX analysis that can be applied to any type of fiber access network with consideration of changed component cost in time and variable take rates, and comparing the total cost (i.e., sum of CAPEX and OPEX) for the selected representative architectures with and without protection for business and residential users in relation to reliability performance. The aim is to give a guideline for the design of the most cost-effective protection schemes, while maintaining acceptable service reliability.

  • 48.
    Chen, Jiajia
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Tacca, Marco
    Fumagalli, Andrea
    Dynamic routing based on information summary-LSA in WDM networks with wavelength conversion2008In: Proceedings of 2008 10th Anniversary International Conference on Transparent Optical Networks, ICTON, NEW YORK: IEEE , 2008, p. 50-54Chapter in book (Other academic)
    Abstract [en]

    This Study investigates the use of information Summary (IS) applied to the advertised available resources to reduce the amount of link state advertisement (LSA) overhead, which is necessary to achieve distributed dynamic routing in WDM networks,. As illustrated in the Study, if carefully designed, the resulting IS-LSA protocol can significantly contain the size of the advertised data set without excessively affecting the network performance, i.e., the blocking probability caused by routing decisions based on incomplete link state information.

  • 49.
    Chen, Qiman
    et al.
    South China Normal Univ, ZJU SCNU Joint Res Ctr Photon, Guangzhou, Guangdong, Peoples R China..
    Yang, Bing
    South China Normal Univ, ZJU SCNU Joint Res Ctr Photon, Guangzhou, Guangdong, Peoples R China..
    Zhang, Dan
    South China Normal Univ, ZJU SCNU Joint Res Ctr Photon, Guangzhou, Guangdong, Peoples R China..
    Zhang, Qiong
    Fujitsu Labs Amer Inc, Richardson, TX USA..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Flexible Service Chain Mapping in Server-Centric Optical Datacenter Networks2018In: 2018 ASIA COMMUNICATIONS AND PHOTONICS CONFERENCE (ACP), IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    We investigate flexible service chain mapping in server-centric optical terconnects, handling virtual network function (VNF) dependency operly. Blocking probability decreases by a factor of 10 when signing multiple VNFs in the same server is allowed.

  • 50. Chen, X.
    et al.
    Lin, R.
    Cui, J.
    Gan, L.
    Pang, Xiaodan
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Ozolins, O.
    Udalcovs, A.
    Jiang, T.
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Popov, Sergei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Photonics.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Tang, M.
    Fu, S.
    Liu, D.
    TDHQ Enabling Fine-Granularity Adaptive Loading for SSB-DMT Systems2018In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 30, no 19, p. 1687-1690, article id 8443443Article in journal (Refereed)
    Abstract [en]

    In this letter, we introduce time domain hybrid quadrature amplitude modulation (TDHQ) for the single sideband discrete multi-tone systems. The experimental results reveal that with a single precoding set and the proposed adaptive loading algorithm, the TDHQ scheme can achieve finer granularity and therefore smoother continuous growth of data rate than that with the conventional quadrature amplitude modulation. Besides, thanks to the frame construction and the tailored mapping rule, the scheme with TDHQ has an obviously better peak to an average power ratio. 

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