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  • 2951.
    Thi Nguyen, Ngoc-Hien
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Quantitative Analysis of Ambulance Location-allocation and Ambulance State Prediction2015Licentiate thesis, monograph (Other academic)
  • 2952.
    Thiessen, Christian
    KTH, School of Information and Communication Technology (ICT).
    Resilient routing and spectrum assignment in Elastic Optical Networks under Dynamic Traffic2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Transparent Elastic Optical Networks (EON) are seen as a promising solution for future optical transport networks to keep up with internet traffic growth, as they allow provisioning connections with different bandwidth requirements in an efficient way. To achieve high spectrum efficiency in these networks, making good Routing, Modulation and Spectrum Assignment (RMLSA) decisions is essential. Since fiber cuts are common, resiliency against single-link failures is another important topic. This can be provided efficiently through shared-path protection (SPP), which in turn complicates the RMLSA problem.

    Existing routing, modulation and spectrum assignment algorithms for SPP focus on the two-step approach, where primary paths are selected independently of their backup path options. However, selecting a different primary path can allow for a better backup path with higher shareability of backup resources if primary and backup path pairs are considered together. Previous studies on SPP in EONs mostly consider the static traffic scenario. Under a dynamic traffic scenario, where unpredictable connection re-quests arrive and terminate over time, fragmentation of spectral resources has a significant impact on the network performance.

    In this thesis, a new algorithm is proposed for SPP in EONs against single-link failures where primary and backup path pairs are selected jointly, thereby minimizing fragmentation and maximizing shareability which leads to better network performance in terms of blocking probability. Unlike existing algorithms, the primary and backup path and spectrum are decided simultaneously from a set of candidate path pairs and the spectrum assignment is done using a hybrid cost metric. The metric is a weighted combination of existing metrics that integrates fragmentation and shareability into a multi-objective function.

    Using network traffic simulations in two reference networks, the effect of the different cost functions on the algorithm’s behavior is explored and an optimal set of weights is determined. With this parameterization, traffic simulations in a scaled-down sample US network topology with load values of 190-240 Erlang, corresponding to blocking probabilities of 0.1% to 1%, show an average improvement over the reference algorithm of 79% in blocking probability, 6.9% in shareability and 5.9% in spectrum fragmentation. It is also shown that most of this improvement is caused by joint primary-backup path assignments. The hybrid cost function reduces blocking by a further 10%.

  • 2953.
    Thießen, Christian
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Cavdar, Cicek
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Fragmentation-aware survivable Routing and Spectrum Assignment in elastic optical networks2014In: Proceedings of 2014 6th International Workshop on Reliable Networks Design and Modeling, RNDM 2014, IEEE , 2014, p. 97-101Conference paper (Refereed)
    Abstract [en]

    Transparent elastic optical networks (EON) allow provisioning connections with different bandwidth requirements in an efficient way. To achieve the high spectrum efficiency under dynamic traffic scenario, fragmentation-aware Routing, Modulation and Spectrum Assignment (RMSA) decisions is essential. Since fiber cuts are common, resiliency against single-link failures is another important topic. This can be provided efficiently through shared-path protection, which in turn complicates the connection provisioning problem. Unlike existing algorithms that decide first the primary and then the backup path, we introduce an algorithm in this paper that considers pairs of primary and backup paths. To select a candidate pair, we use a hybrid cost function that combines three different objectives: (1) the separation of primary and backup connections to different ends of the spectrum; (2) fragmentation-awareness as a pro-active provisioning objective trying to avoid fragmentation especially among primary resources and (3) maximization of shareability of backup resources among primary paths of link-disjoint connections. Using network level simulations in a scaled-down sample US network with load values of 190-240 Erlang, and bandwidth requests corresponding to 1% blocking probability, an average improvement of 79% compared to a recently presented reference algorithm is shown.

  • 2954.
    Thorell, Per
    KTH, Superseded Departments, Teleinformatics.
    Time Warped PolynomialsApplied to Video Compression1996Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Time-warped polynomials provide a way of generating bases that is optimized to the characteristics of a particular signal. In this master thesis, the time-warped polynomial transform and its possible applications in the field of video compression is analyzed. It was found that the optimal warped transform suggested by W. Philips does not work well for image data, but that a modification gives much better results. The main weaknesses of the transform in the context of video compression is the need for computing power and the difficulties to apply the transform on two-dimensional data.

  • 2955.
    Thorslund, Birgitta
    et al.
    Linköping University, The Swedish Institute for Disability Research. Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Peters, Björn
    Linköping University, The Swedish Institute for Disability Research. VTI, Linköping.
    Jansson, Jonas
    VTI, Linköping.
    Principle Other Vehicle Warning - POVW: En simulatorstudie för utvärdering av automatiserad ljud- och ljusvarning från mötande fordon2012Conference paper (Other academic)
    Abstract [en]

    A simulator study of a critical frontal collision situation was conducted in order to examine usefulness of different warning modalities from a principal other vehicle (POV). In total, 48 participants drove 30 km while performing a secondary task, announced by a vibration in the seat, and experiencing light and/or sound warnings from oncoming traffic.

    For comparison field measurements of light and horn sound levels were collected. The measurements were used for the implementations in the simulators graphics- and sound system respectively.

    The study aims at providing basic understanding of driver responses to headlight and sound warning coming from another vehicle. A possible application is the implementation of systems for automatic activation of these warnings. Systems for automatic activation of brakes and steering are currently entering the market. These systems use proximity sensors to monitor the state of surrounding road users. Depending on the specific situation the effort/possibility to avoid or mitigate an accident may differ significantly between the principle road users of a pending collision, e.g. one road user (1) may easily avoid a collision while another (2) may not be able to do so. The only possibility for the second road user (2) to avoid a collision in such a situation is to issue a warning to the first (1), so that he/she may take evasive actions. Connecting the horn and the headlight to already existing sensor system, for automatic warning activation, is a cost effective means to provide such a warning. These types of warnings, could of course, also be triggered manually by the driver. The aim of this project is to evaluate the effectiveness of such a warning and also to validate if the warning between the road users is experienced as intended and whether the warning is an effective countermeasure for avoiding accidents.

    There is limited research on how to design warning signals to avoid collision. In a simulator study auditory collision warnings with increasing intensity have been shown more effective than other types of auditory warnings (Gray, 2011). According to research regarding warning signals in general, auditory warnings should, if possible impart the nature of the events to the user. (Edworthy, 1995a). Research have also shown that people can match the frequency with which they respond to alarms to the false alarm rate, that increasing the perceived urgency of an alarm decreases reaction time and that increasing the number of modalities in which a warning is presented decreases reaction time. (Edworthy, 1995b)

     

    Another objective of this study was to develop simulation technology for a realistic sensation of headlight glare and horn sound of an oncoming vehicle. The effect of using these signaling systems in a critical situation was then studied in the VTI simulator III (Nordmark, Jansson, Palmkvist, & Sehammar, 2004). The aim of the present study was to find a suitable warning signal, triggered by a first vehicle, which makes the driver of a second vehicle react fast enough to avoid a collision. It is important that the driver understands the message of the signal to be able to distinguish between “normal” horn and blink signals which are not time critical and this time critical warning. An additional cognitive task was used to distract the drivers to create a critical event.

    The driving scenario was a rural road (70 kph speed limit) where the driver of a vehicle was distracted by means of a visual distraction task (reading and recalling letters from a screen placed at a relative large down angle (40-45 degrees), and then “pushed” across the median towards an oncoming vehicle, by introducing a steering angle in the simulated vehicle without submitting that information to the motion platform. The oncoming vehicle detects that the situation is critical and attempts to use headlight glare and horn sound to warn the driver of the vehicle that is drifting into oncoming traffic.

    A within person design with four experimental warning conditions were used to evaluate the modality of the warning signals. Non critical noise and light signals from POV represented for example a greeting or a wish to make the driver aware of the headlight. The purpose of the non-critical signals was to evaluate if the driver understands the difference between the critical and non-critical signal. Measurements used to monitor driver behavior were lateral distance between the vehicles when passing, and driver reaction time (in term of steering wheel and brake pedal response). This was accompanied with subjective ratings during and after the test drive, both to evaluate the realism of the simulated event and the usefulness of the warning provided by the meeting vehicle.

    The participants drove the Subject Vehicle (SV) with the instruction to drive as he or she usually does. In total, the participant experienced the critical event 5 times during this trip. Three different warning signals were presented, one at each event. The warning coming from the encountering vehicle was given through an automatic system triggering the horn and/or the lights of the POV. There was also a baseline event when no warning was given. The warning signals was presented in balanced order to avoid effects of which signal is presented first etc. The signal presented at the first event was also presented at the fifth event. This was to be able to investigate the learning effect. The non-critical noise and light signals were presented in the gaps between two warning signals.

    The analysis is in process and will be completed in time for the full length paper submission. Preliminary results from the questionnaire show that participants have noticed the following warnings during the drive; sound (n=44), light (n=39), sound and light (n=32). Most participants think that the warnings were useful (n=31). Sound and vibration in the simulator is thought to be realistic. Participants are very positive to the announcement of the secondary task through a vibration in the seat. Most participants are positive to all three warning types; light (n=36), sound (n=31), light and sound (n=41).

  • 2956. Thrybom, Linus
    et al.
    Gidlund, Mikael
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Neander, Jonas
    Key Requirements for Successful Deployment of Positioning Applications in Industrial Automation2013Conference paper (Refereed)
  • 2957.
    THUMMALAPALLI, STALINBABU
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Wi-Fi Indoor Positioning2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Global Positioning System (GPS) is a space based satellite navigation system. It provides location and time information in all weather, anywhere on the earth. Unfortunately GPS fails to give position indoors, because it requires a direct line of sight to several satellites. Indoor locating systems can thus not use GPS, because signal strengths are weakened or cancelled by building structures. So we need another technology for positioning indoors. Wireless indoor positioning systems are very popular in recent years. These systems are successfully used to asset tracking. By using ultrasound or lasers we can find accurate positioning, but this involves larger costs and energy requirements.Indoor wireless positioning based on received RF signal strength has gained more popularity for researchers in recent years. Wireless communication is a rapidly growing technology used in both home and business networking. Currently wireless networks are set up in institutes, hospitals, shopping malls, and airports and so on. Wi-Fi location determination is a technology; it utilizes existing Wi-Fi equipment such as those installed in personal computers, PDAs and mobile phones. The technology uses modulated Wi-Fi transmission signals to detect the presence of a device, which does not necessarily have to be connected to the network. The system is able to triangulate the position of the device based on the signals received from several access points. Some researchers implemented positioning algorithms to find the position indoors. In those algorithms some popular algorithms are signal strength mean value algorithm, K nearest neighbor’s algorithm, and Bayesian positioning algorithm. Before positioning, we can also measure the signal strength values in a reference point inside the building and use those values to build a database. The database contains coordinates of reference points, orientation and set of signal strength measurements linked to the access points. In positioning phase we can then measure the signal strength and compare those signals with an already built database for finding the position. This type of position finding is known as finger printing method.This paper provides an overview of the existing positioning techniques. The main aim of this thesis is to find the accurate position indoors. For finding the accurate position we are using the finger print database model. In addition to the finger print database model we are considering the walking speed of the user and the history of previous signal strength values. In this thesis we proposed a User Prediction Algorithm, using this algorithm we can find the position of object or user with less error and also we can solve the ambiguity problem to some extent.

  • 2958.
    Thylén, Lars
    et al.
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Berglind, Eilert
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Plasmonics, coherent light matter interactions and photonic crystals: Shaping the future of photonics?2006In: ICTON 2006: 8th International Conference on Transparent Optical Networks, Vol 1, Proceedings: ICTON, MPM, INDUSTRIAL, PICAW, GOWN / [ed] Marciniak, M, 2006, p. 1-5Conference paper (Refereed)
    Abstract [en]

    Photonics is far behind electronics in maturity. There are no large RAM type memories, the circuits are orders of magnitude larger than electronics IC circuits, the functionality is comparatively low. But it appears that few or none of these factors are fundamentally impossible to overcome, and perceiving the enormous potential in photonics, the field continues to be an area of dynamic rapid development. In this paper some of the emerging possibilities that exist are explored, and the possibilities to utilize these comparatively new phenomena to widen the application envelope of photonics technology and generate functions not normally associated with photonics are briefly discussed. These developments could lead to quantum leaps in photonics devices, to complement the forceful engineering improvements.

  • 2959.
    Thylén, Lars
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Holmström, Petter
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Wosinski, Lech
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Jaskorzynska, Bozena
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Naruse, Makoto
    National Institute of Information and Communications Technology, , 4-2-1 Nukui-kita, Koganei, Tokyo, Japan 184-8795.
    Kawazoe, Tadashi
    School of Engineering, The University of Tokyo.
    Yan, Min
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Fiorentino, M.
    Westergren, Urban
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Optics and Photonics, OFO.
    Nanophotonics for Low-Power Switches2013In: Optical FiberTelecommunications VIA: Components and Subsystems / [ed] Ivan Kaminow, Tingye Li and Alan Willner, Elsevier, 2013, p. 205-241Chapter in book (Other academic)
    Abstract [en]

    This chapter treats several approaches for employing nanophotonics or near-nanophotonics concepts to create low-power switches. The partly interrelated issues of low power dissipation and small device footprint are elucidated and figures of merit for switches formulated. Both optically and electronically controlled optical switches are treated and the crucial role of material development emphasized, illustrated by several examples, including both theoretical analysis of switch concepts and experimentally realized switches. Thus, electronically controlled switches based on hybrid, metamaterial and nanoparticle plasmonics, electrooptic polymers as well as switches based on silicon and photonic crystals are discussed. The all-optical switches focus on third-order nonlinear effects and carrier-induced refractive-index changes in III-V materials, as well as on emerging concepts of near-field-coupled quantum-dot switches. A brief comparison to electronic switches is done.

  • 2960.
    Tiainen, Arttu
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Inter-Satellite Link Antennas: Review and The Near Future2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The emerging trend in distributed spacecraft systems of using multiple spacecraft which share functions as opposed to independent spacecraft has given opportunities for missions previously infeasible. Inter-satellite link (ISL) communications provide a direct link within the space segment without need of an intermediate ground segment to relay the data. As the distributed spacecraft systems (DSS) have become less exotic and more complex, the need and demand for inter-satellite antenna systems has increased and the requirements for the antenna systems more diverse and become more demanding. This document is a research of the antennas currently used for ISL, already flown or will be launched in the near future. While the emphasis is strongly in the antennas, the other parts of the ISL communications sub-systems are observed. To limit the scope of the work, optical cross links are not observed in this document. ISL used only for very close proximity, such as several kilometres, are given only limited scope as the main challenges on those do not involve antennas. Furthermore, the major emphasis is given to systems which can be seen as commercially important. This document is divided in five main sections and the conclusions. In the first section the features and the challenges of ISLs are described. In the second section a parametrisation system for antennas is defined and this system is used in following sections to describe the ISL sub-systems and antenna used in them. The third part is a survey of recently flown space missions with ISLs. The fourth section is a survey on the missions which are scheduled to fly in near future and a brief survey of the solutions offered by satellite service providers and manufacturers. Due to the limited technical data available, the fourth section contains far more reverse engineering and assumptions than the survey on legacy missions. The fifth section describes the several families of ISL suitable antennas under development and discusses about several topics which relate to the ISL antenna development. In this part also are defined several example antenna specifications and the applications of those. The study concludes that antennas suitable for inter-satellite links are not inherently different from ground segment communication antennas of the S/C. The major difference is the need for greater coverage, which can be attained by multiple antenna elements, beam steering or antenna pointing. Specific considerations are needed to be taken into account and often the use of ISLs will increase the technical challenges, but it can provide solutions for problems which cannot be solved otherwise.

  • 2961.
    Tian, Ye
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    A Web Server for Sensors2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis describes the project “A new Web Server for sensors”. The project has created a demonstration web service that can receive data from sensors ( both fixed sensors and movable sensors) and distribute the received information in the form of web pages. These web pages can provide forms that enable the user to enter commands which are to be given to sensors. The aim of this thesis project was to design and evaluate web-based application which could utilize sensor data. In this project, we focused on two aspects: (1) web access to sensors and (2) the potentialmobility of sensors. The web server provides web server mediated access to the sensors. Additionally, this project examined how to integrate a sensor with a mobile device, such as a personal data appliance. The web server provides an easy acces smechanism to users who want to use and control sensors. Those users can flexibly us etheir web browser to access to sensors through our web server. Moreover, a sensor could move, for example because it is integrated with a personal data appliance. The mobility of sensors increases the sensing scope of sensors because the sensors are notfixed in position. Such sensors can sense the environment along the path that they are moved.

    To achieve the goals of this thesis project, we analyzed what are the basic parts and functions that should exist for sensors in the web server. Furthermore, the thesis analyzed how a sensor can be integrated with a personal data appliance, for instance,how to supply the power to sensor; and how to synchronize data between the sensor and personal data appliance. As a result of this project, a web server with some of the necessary functions was developed. An approach of how to integrate a sensor with a personal data appliance is specified in this thesis.

    The thesis begins with an analysis of some existing solutions. Their advantages were used to specify the requirements for our own solution. The thesis describes the design and implementation of this proposed solution. Next the thesis describes the testing and evaluation of this solution in the context of this project. The thesis ends with some conclusions and suggests future work.

  • 2962. Tian, Ye
    et al.
    Li, Xiong
    Sangaiah, Arun Kumar
    Ngai, Edith
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Song, Zheng
    Zhang, Lanshan
    Wang, Wendong
    Privacy-preserving scheme in social participatory sensing based on Secure Multi-party Cooperation2018In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 119, p. 167-178Article in journal (Refereed)
    Abstract [en]

    Social participant sensing has been widely used to collect location related sensory data for various applications. In order to improve the Quality of Information (QoI) of the collected data with constrained budget, the application server needs to coordinate participants with different data collection capabilities and various incentive requirements. However, existing participant coordination methods either require participants to reveal their trajectories to the server which causes privacy leakage, or tradeoff the location accuracy of participants for privacy, thereby leading to lower QoI. In this paper, we propose a privacy-preserving scheme, which allows application server to provide quasi-optimal QoI for social sensing tasks without knowing participants’ trajectories and identity. More specifically, we first suggest a Secure Multi-party Cooperation (SMC) based approach to evaluate participant’s contribution in terms of QoI without disclosing each individual’s trajectory. Second, a fuzzy decision based approach which aims to finely balance data utility gain, incentive budget and inferable privacy protection ability is adopted to coordinate participant in an incremental way. Third, sensory data and incentive are encrypted and then transferred along with participant-chain in perturbed way to protect user privacy throughout the data uploading and incentive distribution procedure. Simulation results show that our proposed method can efficiently select appropriate participants to achieve better QoI than other methods, and can protect each participant’s privacy effectively.

  • 2963. Tian, Ye
    et al.
    Wang, Wendong
    Wu, Jie
    Kou, Qinli
    Song, Zheng
    Ngai, Edith C.-H.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Privacy-preserving social tie discovery based on cloaked human trajectories2017In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 66, no 2, p. 1619-1630Article in journal (Refereed)
  • 2964.
    Tiloca, Marco
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    De Guglielmo, Domenico
    University of Pisa, Italy.
    Dini, Gianluca
    University of Pisa, Italy.
    Anastasi, Giuseppe
    University of Pisa, Italy.
    Das, Sajal K.
    Missouri University of Science and Technology, US.
    DISH: DIstributed SHuffling against selective jamming attack in IEEE 802.15.4e TSCH networks2018In: ACM transactions on sensor networks, ISSN 1550-4867, E-ISSN 1550-4859Article in journal (Refereed)
    Abstract [en]

    The MAC standard amendment IEEE 802.15.4e is designed to meet the requirements of industrial and critical applications. In particular, the Time Slotted Channel Hopping (TSCH) mode divides time into periodic, equally-sized, slotframes composed of transmission timeslots. Then, it combines timeslotted access with multi-channel and channel hopping capabilities, providing large network capacity, high reliability and predictable latency, while ensuring energy efficiency. Since every network node considers the same timeslots at each sloframe and selects physical channels according to a periodic function, TSCH produces a steady channel utilization pattern. This can be exploited by a selective jammer to entirely thwart communications of a victim node, in a way that is stealthy, effective and extremely energy efficient. This paper shows how a selective jamming attack can be successfully performed even though TSCH uses the IEEE 802.15.4e security services. Furthermore, we propose DISH, a countermeasure which randomly permutes the timeslot and channel utilization patterns at every slotframe in a consistent and completely distributed way, without requiring any additional message exchange. We have implemented DISH for the Contiki OS and tested its effectiveness onTelosB sensor nodes. Quantitative analysis for different network configurations shows that DISH effectively contrasts selective jamming with negligible performance penalty.

  • 2965. Timo, R.
    et al.
    Oechtering, Tobias J.
    KTH, School of Electrical Engineering (EES), Communication Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Wigger, M.
    Successive refinement with conditionally less noisy side information2013In: IEEE International Symposium on Information Theory: Proceedings, 2013, p. 2985-2989Conference paper (Refereed)
    Abstract [en]

    We consider the successive refinement of information problem with decoder side information. The rate-distortion region is unknown in general; Steinberg & Merhav and Tian & Diggavi solved it in the special case of degraded side information. We extend this special case to a new setup, conditionally less noisy side information, and we give a single-letter solution when one distortion function is deterministic.

  • 2966.
    Tirkkonen, Olav
    et al.
    Aalto University, Helsinki, Finland & Cornell University, New York, NY, USA.
    Li, Zexian
    Nokia Bell Labs, Espoo, Finland.
    Wei, Lu
    University of Michigan, Dearborn, MI, USA.
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    On-Off Necklace Codes for Asynchronous Mutual Discovery2017In: 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017Conference paper (Refereed)
    Abstract [en]

    We consider mutual discovery of asynchronous wireless transceivers with a fixed activity ratio. On-off activity patterns are slotted, and repeat in discovery frames. For discovery it has to be guaranteed that the activity patterns of two transceivers are not overlapping. We design necklace codes determining activity patterns to guarantee discovery within a discovery frame, so that two asynchronous transceivers always have non-overlapping activity patterns. The number of distinct patterns is analyzed as a function of discovery frame length, and on-off activity ratio. As an application example, we consider the discovery problem for vehicle-to-vehicle communication. To guarantee discovery of far-away vehicles, discovery sequences providing processing gain, and necklace coded activity patterns are needed. We find that billions of discovery code identities can be provided with a repetition frequency that is high enough to guarantee a missed discovery probability less than 10−6.

  • 2967.
    Tisma, Eddie
    et al.
    Jönköping University, School of Engineering, JTH, Computer and Electrical Engineering.
    Nilsson, Johan
    Jönköping University, School of Engineering, JTH, Computer and Electrical Engineering.
    Development of Web portal for health centre Aroma in Vetlanda2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This exam paper has been made with the health care center Aroma in Vetlanda. The work was to deliver a complete web portal with an integrated booking system. The objectives were to provide a complete informative website for Aromas users with the option to make an appointment for a vaccination or health certificate, order prescriptions and get update information directly published by Aromas staff. And to give the staff of Aroma a graphical Web interface to manage the content and the booking system.The report goes through the basic language used and why. Further it takes up it how works and how the final product looks and behaves.

  • 2968.
    Tobias, Eklund
    et al.
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Social Sciences, Department of Informatics and Media.
    Spehar, Joakim
    CPlanner: Kursplaneringsprototyp med Design Science och Scrum2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Development of planning system is a complex design problem that requires both a high degree of flexibility but also structure. In the context of planning, there are several actors, activities and resources that must be considered. Expertise in planning is often concentrated in a few key individuals. It is therefore no coincidence that many businesses, organizations and even universities currently conducts its planning in proven single-user system like Excel even though there is a strong need for standardized multi-user system. Uppsala University is no exception, despite its size, with over 40,000 students, 6,200 employees, 130 programs and 2000 courses. Course planning is conducted using single-user system and which is dependent on a number of key individuals to plan to work. The essay aims to investigate and illustrate the problems that are associated with the development of the planning system by developing a prototype of a course scheduling system. The research strategy used is Design Science and the development methodology that is used is Scrum. The prototype has been evaluated regularly during development through formative evaluation. The essays knowledge contribution is methodological knowledge that shows both how Scrum and Design Science can be combined and model knowledge, which shows the basic structure of a course scheduling system.

  • 2969.
    Toczé, Klervie
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    A Taxonomy for Management and Optimization of Multiple Resources in Edge Computing2018In: Wireless Communications & Mobile Computing, ISSN 1530-8669, E-ISSN 1530-8677, article id 7476201Article, review/survey (Refereed)
    Abstract [en]

    Edge computing is promoted to meet increasing performance needs of data-driven services using computational and storage resources close to the end devices at the edge of the current network. To achieve higher performance in this new paradigm, one has to consider how to combine the efficiency of resource usage at all three layers of architecture: end devices, edge devices, and the cloud. While cloud capacity is elastically extendable, end devices and edge devices are to various degrees resource-constrained. Hence, an efficient resource management is essential to make edge computing a reality. In this work, we first present terminology and architectures to characterize current works within the field of edge computing. Then, we review a wide range of recent articles and categorize relevant aspects in terms of 4 perspectives: resource type, resource management objective, resource location, and resource use. This taxonomy and the ensuing analysis are used to identify some gaps in the existing research. Among several research gaps, we found that research is less prevalent on data, storage, and energy as a resource and less extensive towards the estimation, discovery, and sharing objectives. As for resource types, the most well-studied resources are computation and communication resources. Our analysis shows that resource management at the edge requires a deeper understanding of how methods applied at different levels and geared towards different resource types interact. Specifically, the impact of mobility and collaboration schemes requiring incentives are expected to be different in edge architectures compared to the classic cloud solutions. Finally, we find that fewer works are dedicated to the study of nonfunctional properties or to quantifying the footprint of resource management techniques, including edge-specific means of migrating data and services.

  • 2970.
    Toczé, Klervie
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Where Resources meet at the Edge2017In: 2017 IEEE INTERNATIONAL CONFERENCE ON COMPUTER AND INFORMATION TECHNOLOGY (CIT), IEEE , 2017, p. 302-307Conference paper (Refereed)
    Abstract [en]

    Edge computing is a recent paradigm where network nodes are placed close to the end users, at the edge of the network. Efficient management of resources within this configuration is crucial due to scarcity and geographical spreading of edge resources. We begin by a brief description of the edge paradigm, the most generic edge architecture, and the terminology associated to it. Then, we propose and elaborate on a preliminary taxonomy for edge resource management, together with a substantial review of works in the area. Finally, we identify some research challenges.

  • 2971.
    Tollmar, Konrad
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Lungaro, Pietro
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Valero, Alfredo Fanghella
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Mittal, Ashutosh
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Mobile Service Laboratory (MS Lab).
    Beyond foveal rendering: Smart eye-tracking enabled networking (SEEN)2017In: ACM SIGGRAPH 2017 Talks, SIGGRAPH 2017, Association for Computing Machinery (ACM), 2017, article id 3085163Conference paper (Refereed)
    Abstract [en]

    Smart Eye-tracking Enabled Networking (SEEN) is a novel end-to-end framework using real-time eye-gaze information beyond state-of-the-art solutions. Our approach can effectively combine the computational savings of foveal rendering with the bandwidth savings required to enable future mobile VR content provision.

  • 2972.
    Tomar, Abhineet Singh
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Modern Electrical/Electronic Infrastructure for Commercial Trucks: Generic Input/Output nodes for sensors and actuators in Commercial Trucks2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The presence of electrical and electronic circuits in commercial trucks has increased at a very fast rate during recent decades. With advancements in embedded systems and the introduction of electric controls in the automotive industry, the design of complex electric systems for the vehicles has become one of the major design challenges. In the commercial truck industry, the development cycles are almost a decade long. Therefore, it is a big challenge to introduce a new architecture to accommodate the modern automotive technologies in the upcoming generation of trucks.

    Currently, the commercial truck industry relies highly on a federated electrical/electronic (E/E) architecture. In this architecture, Electronic Control Units (ECU) are responsible for computation and Input/Output operations. These ECUs are clustered into different domains based on their respective functions. However, these domains are not isolated from each other. These modules communicate with each other using a vehicular network, which is typically a controller area network in the current trucks.

    In the automotive industry, automation is increasing at a fast pace. As the level of automation increases, the need for high computation also increases, which increases the overall costs. This study aims to address this problem by introducing an integrated E/E architecture where all the computational power is concentrated at one place (or perhaps two or three places to allow for redundancy). This study proposes to introduce a lowcost replacement for the current ECUs with more limited computational power but with generic input/output interfaces.

    This thesis provides the reader with some background of the current E/E architecture of commercial trucks and introduces the reader to ECUs. Additionally, the relevant network architectures and protocols are explained. A potential solution, based upon the centralized computation based E/E architecture and its implementation are discussed followed by a detailed analysis of the replacements for ECUs. The result of this analysis, if adopted, should result in a reduction of manufacturing and design costs, as well as make the production and maintenance process easier. Moreover, this should also have environmental benefits by reducing fuel consumption.

  • 2973.
    Tombaz, Sibel
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    On the Design of Energy Efficient Wireless Access Networks2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for new services and ubiqutious connectivity, will further increase the energy consumption. This situation imposes a big challenge for mobile operators not only due to soaring cost of energy, but also increasing concern for global warming and sustainable development.

    This thesis focuses on the energy efficiency issue at the system level and studies how to incorporate energy-awareness into the design of future wireless access networks. The main contributions have been given in the areas of energy efficiency assessment, architectural and operational solutions, and total cost of investment analysis.

    The precise evaluation of energy efficiency is the first essential step to determine optimized solutions where metrics and models constitute the two key elements.We show that maximizing energy efficiency is not always equivalent to minimizing energy consumption which is one of the main reasons behind the presented contradictory and disputable conclusions in the literature. Further we indicate that in order to avoid the debatable directions, energy efficient network design problems should be formulated with well defined coverage and capacity requirements. Moreover, we propose novel backhaul power consumption models considering various technology and architectural options relevant for urban and rural environments and show that backhaul will potentially become a bottleneck in future ultra-high capacity wireless access networks.

    Second, we focus on clean-slate network deployment solutions satisfying different quality of service requirements in a more energy efficient manner. We identify that the ratio between idle- and transmit power dependent power consumption of a base station as well as the network capacity requirement are the two key parameters that affect the energy-optimum design.While results show that macro cellular systems are the most energy efficient solution for moderate average traffic density, Hetnet solutions prevail homogeneous deployment due to their ability to increase the capacity with a relatively lower energy consumption and thus enable significant energy savings in medium and high capacity demand regions.

    Moreover, we investigate the energy saving potential of short-term energy aware management approach, i.e., cell DTX, taking advantage of low resource utilization in the current networks arising from strict QoS requirements. With the help of developed novel quantitative method, we show that Cell DTX brings striking reduction in energy consumption and further savings are achievable if the networks are designed taking into account the fact that network deployment and operation are closely related.

    Finally, we develop a general framework for investigating the main cost elements and for evaluating the viability of energy efficient solutions.We first reveal the strong positive impact of spectrum on both energy and infrastructure cost and further indicate that applying sustainable solutions might also bring total cost reduction, but the viability highly depends on unit cost values as well as the indirect cost benefits of energy efficiency.

    Results obtained in this dissertation might provide guidelines for the network designers to achieve future high-capacity and sustainable wireless access networks.

  • 2974.
    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.
    Towards Green Wireless Access Networks: Main Tradeoffs, Deployment Strategies and Measurement Methodologies2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for capacity will further increase the energy consumption. Thus, improving energy efficiency has a great importance not only for environmental awareness but also to lower the operational cost of network operators. However, current networks which are optimized based on non-energy related objectives introduce challenges towards green wireless access networks. In this thesis we investigate the solutions at the deployment level and handle energy efficiency assessment issues in wireless access networks.

    The precise characterization of the power consumption of the whole network has a crucial importance in order to obtain consistent conclusions from any proposed solution at the network level. For this purpose, we propose a novel power consumption model  considering  the impact of backhaul for two established technologies, i.e., fiber and microwave, which is often ignored in the literature. We show that there is a tradeoff between the power saved by using low power base stations and the excess power that has to be spent for backhauling their traffic which therefore needs to carefully be included into energy efficiency analysis. Furthermore, among the solutions that are analyzed, fiber-based backhaul solution is identified to outperform microwave regardless of the considered topology. The proposed model is then used to gain a general insight regarding the important design parameters and their possible impact on energy- and cost oriented network design. To this end, we present a  high-level framework to see the main tradeoffs between energy, infrastructure cost, spectrum and show that future high-capacity systems are increasingly limited by infrastructure and energy costs where spectrum has a strong positive impact on both.

    We then investigate different network deployment strategies to improve the energy efficiency where we focus on the impact of various base station types, cell size, power consumption parameters and the capacity demand. We propose a refined power consumption model where the parameters are determined in accordance with cell size. We show that network densification can only be justified when capacity expansion is anticipated and over-provisioning of the network is not plausible for greener network. The improvement through heterogeneous networks is indicated to be highly related to the traffic demand where up to 30% improvement is feasible for high area throughput targets.

    Furthermore, we consider the problem of energy efficiency assessment at the network level in order to allow operators to know their current status and quantify the potential energy savings of different solutions to establish future strategies. We propose elaborate metric forms that can characterize the efficiency and a methodology that indicate how to perform a reliable and accurate measurement considering the complexity of wireless networks. We show the weakness of the current metrics reporting the "effectiveness" and how these might indicate disputable improvement directions unless they are properly revised. This illustrates the need for a standardized network level energy efficiency evaluation methodology towards green wireless access.

  • 2975.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Han, San-wook
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Sung, Ki Won
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    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.
    Energy Efficient Network Deployment with Cell DTX2014In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 18, no 6, p. 977-980Article in journal (Refereed)
    Abstract [en]

    Cell discontinuous transmission (DTX) is a newfeature that enables sleep mode operations at base station (BS)side during the transmission time intervals (TTIs) when thereis no traffic. In this letter, we analyze the maximum achievableenergy saving of the cell DTX. We incorporate the cell DTXwith a clean-slate network deployment, and obtain optimal BSdensity for lowest energy consumption satisfying a certain qualityof service (QoS) requirement considering daily traffic variation.The numerical result indicates that the fast traffic adaptationcapability of cell DTX favors dense network deployment withlightly loaded cells, which brings about considerable improvementin energy saving.

  • 2976.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Farias, Fabricio
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. Federal University of Para.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Is backhaul becoming a bottleneck for green wireless access networks?2014In: 2014 IEEE International Conference on Communications, ICC 2014, IEEE , 2014, p. 4029-4035Conference paper (Refereed)
    Abstract [en]

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

  • 2977.
    Tombaz, Sibel
    et al.
    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.
    Sung, Ki Won
    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.
    Friman, Erik
    Miao, Guowang
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    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.
    Energy Efficiency in Network Level: Definition, Measurement and PredictionManuscript (preprint) (Other academic)
    Abstract [en]

    In this paper, network level energy efficiency assessment issues are described in wireless access networks. High level definitions of energy efficiency are introduced and existing heterogeneous metrics proposed in the literature in order to quantify the energy savings are overviewed. The weaknesses of the current metrics in order to evaluate NLEE have been discussed in detail and more elaborate metric forms have been suggested. Then, a NLEE evaluation methodology is proposed to calculate the suggested indicator, and unlike GSMA method it is based on network segmentation, direct measuring in both network and terminal side, and prediction. We believe that network modularization and frequent observation are the only ways in order to understand the reasoning behind the obtained NLEE metric and propose solutions for the improvement. However, it comes with the increased complexity and challenges to be resolved. We present a summary of the most important difficulties, our suggestions and open questions in order to answer “How to accurately assess the NLEE in wireless access network”.

  • 2978.
    Tombaz, Sibel
    et al.
    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.
    Sung, Ki Won
    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.
    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.
    Impact of Densification on Energy Efficiency in Wireless Access Networks2012In: Globecom Workshops (GC Wkshps), 2012 IEEE, IEEE , 2012, p. 57-62Conference paper (Refereed)
    Abstract [en]

    Mobile communication networks alone consume 0.5 percent of the global energy today. Rapidly growing demand for capacity will further increase the energy consumption. Thus, improving energy efficiency has recently gained great interest within the research community not only for environmental awareness but also to lower the operational cost of network operators. Base station deployment strategy is one of the key challenges to be addressed for fulfilling the future capacity demand in an energy efficient manner. In this paper, we investigate the relationship between energy efficiency and densification with regard to network capacity requirement. To this end, we refine the base station power consumption model such that the parameters are determined by the maximum transmit power and develop a simple analytical framework to derive the optimum transmit power that maximizes energy efficiency for a certain capacity target. Our framework takes into account interference, noise and backhaul power consumption. Numerical results show that deployment of smaller cells significantly reduces the base station transmit power, and thus shifts the key elements of energy consumption to idling and backhauling power. Network densification can only be justified when capacity expansion is anticipated.

  • 2979.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Sung, Ki Won
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    On metrics and models for energy-efficient design of wireless access networks2014In: IEEE Wireless Communications Letters, ISSN 2162-2337, E-ISSN 2162-2345, Vol. 3, no 6, p. 649-652, article id 6877636Article in journal (Refereed)
    Abstract [en]

    The energy efficiency of wireless access networks has attracted significant interest, due to escalating energy cost and environmental concerns. How energy efficiency should be measured is, however, still disputed in the literature. In this letter, we discuss the impact of performance metrics and energy consumption models in network dimensioning. We argue that, using a popular metric, the number of bits/Joule may give misleading results, unless the capacity and coverage requirements of the system are carefully defined. We also claim that the energy consumption in the backhaul and the idle power of the base stations have to be taken into account. To support our claims, we demonstrate in a simple example how misleading results can be obtained by using flawed performance metrics.

  • 2980.
    Tombaz, Sibel
    et al.
    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.
    Vastberg, Anders
    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.
    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.
    Energy- and cost-efficient ultra-high-capacity wireless access2011In: IEEE wireless communications, ISSN 1536-1284, E-ISSN 1558-0687, Vol. 18, no 5, p. 18-24Article in journal (Refereed)
    Abstract [en]

    Mobile communication networks alone today consume 0.5 percent of the global energy supply. Meeting the rapidly increasing demand for more capacity in wireless broadband access will further increase the energy consumption. Operators are now facing both investing in denser and denser networks as well as increased energy cost. Traditional design paradigms, based on assumptions of spectrum shortage and high cost base station sites, have produced current cellular systems based on 3G and 4G (LTE) standards. The latter ones are characterized by very high spectrum efficiency, but low energy efficiency. Deployment has favored strategies with few high-power bases stations with complex antenna systems. The key method for indoor coverage has so far been to literally "blast signals through walls" - a solution that is neither energy-efficient nor very sound from a radiation perspective. As environmental aspects may be perceived as important from a societal perspective, the cost remains the short-to medium-term concern for operators of future mobile broadband systems. What becomes evident now is that the so far mostly neglected energy cost will be a major concern. Future system deployment has to balance infrastructure deployment, spectrum, and energy cost components. Ongoing incremental improvements in electronics and signal processing are bringing down the power consumption in the base station. However, these improvements are not enough to match the orders-of-magnitude increase in energy consumption cause by demands for more capacity. It is clear that solutions to this problem have to be found at the architectural level, not just by increasing the efficiency of individual components. In this article we propose a framework for a total cost analysis and survey some recent, more radical, "clean slate" approaches exploiting combinations of new spectrum opportunities, energy-efficient PHY layers, and novel deployment and backhauling strategies that target minimizing overall system cost. The latter involve network deployment tightly tailored to traffic requirements, using low-power micro base stations tailored specifically to decrease the power consumption compared to today's high-power macro base station schemes. To illustrate our findings, a power consumption model for mobile broadband access networks taking backhaul into account is presented, and the main trade-offs between infrastructure, energy, and spectrum costs are analyzed. We demonstrate optimal deployment strategies in some simple scenarios where a certain capacity has to be provided in a dense interference-limited scenario.

  • 2981.
    Tombaz, Sibel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zheng, Zhihao
    KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Zander, Jens
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab). KTH, School of Information and Communication Technology (ICT), Centres, Center for Wireless Systems, Wireless@kth.
    Energy Efficiency Assessment of Wireless AccessNetworks Utilizing Indoor Base Stations2013In: 2013 IEEE 24th International Symposium on Personal Indoor and Mobile Radio Communications (PIMRC), IEEE conference proceedings, 2013, p. 3105-3110Conference paper (Refereed)
    Abstract [en]

    Energy efficiency in mobile radio networks has recently gained great interest due to escalating energy cost and environmental concerns. Rapidly growing demand for capacity will require denser and denser networks which further increase the energy consumption. In this regard, the deployment of small cells under macro-cellular umbrella coverage appears a promising solution to cope with the explosive demand in an energy efficient manner. In this paper, we investigate the impact of joint macro-and femtocell deployment on energy efficiency of wireless access networks, based on varying area throughput requirements. We take into account the the co-channel interference, fraction of indoor users, femto base station density and backhaul power consumption. It is shown that utilizing indoor base stations provide significant energy savings compared to traditional macro only network in urban areas with medium and high user demand where the gain increases up to 75 percent as more data traffic is offloaded to femtocells.

  • 2982. Tomás, L.
    et al.
    Östberg, Per-Olov
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Caminero, B.
    Carrión, C.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Addressing QoS in grids through a fairshare meta-scheduling in-advance architecture2012Conference paper (Refereed)
    Abstract [en]

    Federated Grid resources typically span multiple administrative domains and utilize heterogeneous schedulers. This complexity complicates not only provisioning of quality of service but also management and enforcement of end-user resource utilization allocations. to overcome these problems, we propose to combine high-level meta-scheduling techniques with lower-level fairs hare prioritization mechanisms to create a framework that improves end-user quality of service in heterogeneous distributed computing environments. to illustrate the approach we present a prototype architecture based on two existing systems, the meta-scheduling framework SA-Layer and the distributed fairs hare prioritization system Aequus. the proposed architecture constitutes a predictive meta-scheduling architecture that performs fair user-level scheduling prioritization and enacts resource utilization quotas, whilst also providing synergetic effects that improve the performance of the individual system components. to characterize the contribution, the proposed system is evaluated on a test bed consisting of geographically dispersed, heterogeneous computing resources spanning multiple administration domains.

  • 2983. Tong, Xiaoyu
    et al.
    Ngai, Edith C.-H.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A ubiquitous publish/subscribe platform for wireless sensor networks with mobile mules2012In: Proc. 8th International Conference on Distributed Computing in Sensor Systems, IEEE Computer Society, 2012, p. 99-108Conference paper (Refereed)
  • 2984. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Monti, P.
    Minimum Cost Deployment of Radio and Transport Resources in Centralized Radio Architectures2016In: 2016 INTERNATIONAL CONFERENCE ON COMPUTING, NETWORKING AND COMMUNICATIONS (ICNC), IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

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

  • 2985. Tonini, F.
    et al.
    Fiorani, Matteo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Raffaelli, C.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Benefits of joint planning of small cells and fiber backhaul in 5G dense cellular networks2017In: 2017 IEEE International Conference on Communications, ICC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 7997216Conference paper (Refereed)
    Abstract [en]

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

  • 2986.
    Topal, Baran
    KTH, School of Information and Communication Technology (ICT).
    Comparison of Methods of Single Sign-On: Post authentication methods in single sign on2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Single sign-on (SSO) is a session verification mechanism that allows a client to use a single password and name combination to be able to access multiple applications. The mechanism validates the client for all the applications and eliminates the need for authentication prompts when a user switches between applications within a session.

    SSO mechanisms can be classified as software versus hardware or customer-requirements oriented versus server-side arrangements. The five commonly used mechanisms of Single Sign-On currently are: Web Single Sign-On, Enterprise Single Sign-On, Kerberos (or Ticket/Token Authentication), Open ID, and Federation or Federated Identity.

    SSO has the main benefit of allowing a user to access many different systems without having to log on to each and every one of them separately. However, SSO introduces a security risk as once an attacker gains access to a single system, then the attacker has access to all of the systems.

    This thesis describes SSO technology, the Security Assertion Markup Language, and the advantages and risks involved in using SSO. It examines authentication mechanisms and their suitability for SSO integration. The main emphasis is a description of a mechanism that ameliorates some of the disadvantages of SSO by monitoring the user behavior with respect to a template. If a user performs actions that fit the defined template behavior, then the post authentication mechanism will not get activated. If, on the other hand, a user does something unforeseen, the mechanism will not perform authentication for this user, but rather trigger manual authentication. If this manual authentication succeeds, then the user will continue to interact with the system, otherwise user session will be ended.

    This behavior extension authentication mechanism is a method that eases the authentication process in which users are not expected to remember any username and password that can be forgotten easily or have a biometric attribute that can change over time. This method can be integrated to existing web application without a major risk and increase in cost.

  • 2987.
    Torabian Esfahani, Tahmineh
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Stefanidis, Stefanos
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    High Performance Reference Crystal Oscillator for 5G mmW Communications2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Future wireless communications (often referred to as 5G) are expected to operate at much higher frequencies compared to today’s wireless systems. During this thesis, we have investigated the option to use high frequency crystal oscillators, which along with a PLL, will generate the RF LO signal in the mmW range. Different topologies that consume low power and deliver low phase noise for better channel capacity have been studied and presented.

    In this report we provide a detailed analysis of crystal oscillator theory and designand we discuss techniques that we have used to simulate our models. During this project we have encountered various challenges such as parasitic oscillation, start-up behaviour and effects from package modeling. All these issues are discussed in detail while solutions, examples and results are demonstrated. Finally, along with the crystal oscillator we have also proceeded in the design of a buffer for a better input/output isolation. A squarer has been implemented for greater power savings.

  • 2988.
    Tormo Peiró, Julia Alba
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Spectrum sensing based on specialized microcontroller based white space sensors: Measuring spectrum occupancy using a distributed sensor grid2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The continuing increase in the adoption and use of wireless technology aggravates the problem of spectrum scarcity due to the way we utilize the spectrum. The radio spectrum is a limited resource regulated by governmental agencies according to a fixed spectrum assignment policy. However, many studies show that this fixed radio frequency allocation leads to significant underutilization of the radio spectrum creating artificial scarcity, as most of the allocated spectrum is not used all of the time in every location. To meet services growing demands, efficient use of the spectrum is essential. Therefore, there is a need to estimate the radio spectrum utilization in several locations and during different periods of time in order to opportunistically exploit the existing wireless spectrum. Cognitive radio technology aims to search for those portions of the radio spectrum that are assigned to a specific service, but are unused during a specific time and at specific location in order to share these white spaces and thus to reduce the radio spectrum inefficiency.

    In this thesis, we study spectrum utilization in the frequency range from 790MHz to 925MHz. The spectrum sensing has been realized using a number of specialized microcontroller based white space sensors which utilize energy detection, situated in different locations of a building in Kista, Sweden. The occupancy of the frequency bands in this chunk of the spectrum is quantified as the fraction of samples with a power level greater than a threshold. The results from these spectrum measurements show that a significant amount of spectrum in this scanned range around the building is inefficiently used all the time.

  • 2989.
    Tosteberg, Joakim
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    Axelsson, Thomas
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    Development of a Wireless Video Transfer System for Remote Control of a Lightweight UAV2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A team of developers from Epsilon AB has developed a lightweight remote controlledquadcopter named Crazyflie. The team wants to allow a pilot to navigate thequadcopter using video from an on-board camera as the only guidance. The masterthesis evaluates the feasibility of mounting a camera module on the quadcopter andstreaming images from the camera to a computer, using the existing quadcopterradio link. Using theoretical calculations and measurements, a set of requirementsthat must be fulfilled for such a system are identified. Using the requirementsas a basis, various camera products are investigated and the findings presented.A design to fulfill the requirements, using the found products, is proposed. Theproposed design is then implemented and evaluated.

    It is found that the Crazyflie system has the resources necessary to transferan image stream with the quality required for navigation. Furthermore, theimplementation is found to provide the required functionality. From the evaluationseveral key factors of the design that can be changed to further improve theperformance of an implementation are identified. Ideas for future work andimprovements are proposed and possible alternative approaches are presented.

  • 2990.
    Toufanpanah, Monir
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    Decision Support framework: Reliable Federated Single Sign-on2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Identity management is a critical concept for enterprises, and it has turned to more challenging issue since businesses are significantly moving towards service oriented architecture (SOA) with the aim to provide seamless service delivery to their customers, partners and employees. The organizational domains are expanded to blur the virtual borders, simplify the business collaboration and maximize opportunities in the competitive market place, which explicitly shows the essentiality for federating the identities. Real-world identity comprises of different dimensions such as Law, Business, Policy, Technology and Society, therefore reliable digital identity management and successful federation are required to take these dimensions and complexity into consideration.

    Considering variety of academic and industrial researches that report on remarkable demands for identity federation adoption by enterprises, this study has approached federated Identity Management from technological point of view. Technologies provide tools and mechanisms to satisfy the business requirements and enable single sign-on capability in reliable federated platform.

    Different authentication technologies and standards have emerged to enable federated single sign-on (FSSO) implementation as a core service of the FIdM, each with different features and capabilities. This brings more complexity and confusion for experts and decision makers for FIdM adoption and development. To overcome this obstacle and accelerate the data collection and analysis process for decision makers, this research contributes to the filed by providing a conceptual framework to simplify the analysis of underlying technology for decision making process. In this framework 1) a list of state-of-the-art requirements and mechanisms for successful identity federation and reliable SSO is elaborated, 2) Six most prevalent standard authentication technologies along with latest specifications are analysed, explained and assessed against the defined criteria, and 3) several security and privacy consideration are gathered. The usage of framework is monitored and the efficiency of it is evaluated in 2 real business case scenarios by five IT experts and the result is reported.

  • 2991. Tourancheau, S
    et al.
    Brunnström, K
    Netlab: IPTV, Video and Display Quality - Acreo AB .
    Andrén, B
    Le Callet, P
    LCD motion-blur estimation using different measurement methods2009In: Journal of the Society for Information Display, ISSN 1071-0922, E-ISSN 1938-3657, Vol. 17, no 3, p. 239-249Article in journal (Refereed)
    Abstract [en]

    The primary goal of this study was to find a measurement method for motion blur whichis easy to carry out and gives results that can be reproduced from one lab to another. This methodshould be able to also take into account methods for reduction of motion blur such as backlight flash-ing. Two methods have been compared. The first method uses a high-speed camera that permits us todirectly picture the blurred-edge profile. The second one exploits the mathematical analysis of themotion-blur formation to construct the blurred-edge profile from the temporal step response. Meas-urement results and method proposals are given and discussed.

  • 2992.
    Tran, Hung
    et al.
    Malardalen Univ, S-72123 Vasteras, Sweden..
    Zepernick, Hans-Juergen
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems. Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems. Blekinge Institute of Technology, School of Engineering, Department of Signal Processing. Blekinge Institute of Technology, School of Computing. Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Phan, Hoc
    Univ Reading, Reading RG6 6AY, Berks, England..
    On Throughput and Quality of Experience in Cognitive Radio Networks2016In: 2016 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, IEEE , 2016Conference paper (Refereed)
    Abstract [en]

    In this paper, a performance analysis for cognitive radio networks (CRNs) under the outage probability constraint of the primary user and peak transmit power constraint of the secondary user is conducted. Given an automatic repeat request protocol, analytical expressions for the packet delay and throughput of the CRN are derived. Most importantly, these expressions can be used to understand the quality of experience on web services which are assumed to be offered by the considered CRN.

  • 2993.
    Tran, Hung
    et al.
    Malardalen Univ, SWE.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Proactive Attack: A Strategy for Legitimate Eavesdropping2016In: 2016 IEEE Sixth International Conference on Communications and Electronics (ICCE), IEEE, 2016, p. 457-461Conference paper (Refereed)
  • 2994.
    Tran, Hung
    et al.
    Mälardalen University, SWE.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Sibomana, Louis
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Performance of cognitive radio networks under interference constraints of multiple primary users2016In: 2016, 10th International Conference on Signal Processing and Communication Systems, ICSPCS 2016 - Proceedings, IEEE, 2016Conference paper (Refereed)
    Abstract [en]

    In this paper, we study the performance of point-to-point communication in spectrum sharing systems under the peak interference power constraint of multiple primary users. In particular, we assume that the channels undergo independent but not necessarily identically distributed Nakagami-m fading with integer values of fading severity parameter m. The cumulative distribution function and probability density function for the signal-to-noise ratio are derived. Based on these formulas, we obtain analytical expressions for the outage probability, the ergodic capacity, and the symbol error probability. Numerical results are also provided to investigate the impact of the peak interference power-to-noise ratio, the number of primary users, and fading parameters on the performance of the secondary network. © 2016 IEEE.

  • 2995.
    Tran, Le-Nam
    et al.
    University of Oulu.
    Juntti, Markku
    University of Oulu.
    Bengtsson, Mats
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Ottersten, Björn
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Beamformer designs for zero-forcing dirty paper coding2011In: 2011 International Conference on Wireless Communications and Signal Processing, WCSP 2011, IEEE conference proceedings, 2011Conference paper (Refereed)
    Abstract [en]

    We consider the beamformer design for zero-forcing dirty paper coding (ZF-DPC), a suboptimal transmission technique for MISO broadcast channels (MISO BCs). For the sum rate maximization problem under a total power constraint, the existing beamformer designs in the literature are based on the QR decomposition (QRD), which is used to satisfy the ZF constraints. However, the optimality of the QRD-based design has been unknown previously. In this paper, we prove that the QRD-based design is optimal for ZF-DPC for any performance measure under a sum power constraint. For the per-antenna power constraints, the QRD-based designs become suboptimal, and we propose an optimal design, using a convex optimization framework. Low-complexity suboptimal designs are also presented, and numerically shown to achieve a significant fraction of the sum rate provided by the optimal design.

  • 2996.
    Trella, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Lokalisering av skidor i lössnö: Självständigt arbete i Teknisk Fysik2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report studies the possibility of using some sort of radio sender and transmitter in order to position skis lost in powder snow. It is concluded that a RF-solution on the 433 MHz frequency should be the most efficient. Different forms of directional antennas are examined and studies show that in theory the best suited is the so called “Yagi-Uda antenna”. A solution based on using a Receive Signal Strength Indicator value together with the above mentioned directional antenna is developed. To control these different components microprocessors from Atmel is used. These are programmed in C and compiled with Atmel’s own compiler AVR Studio. Despite all efforts it is proven that the prototype does not perform in an adequate way. An alternative solution based on “byte-loss-rate” is then developed and the results are slightly improved. Nevertheless, the directional properties of the antenna are still too poor why other alternatives are discussed. No fully functioning prototype is achieved but good grounds for further development of the prototype into something that fulfills the specifications are produced.

  • 2997. Tremblay, C.
    et al.
    Archambault, E.
    Be´langer, M. P.
    Littlewood, P.
    Clelland, W.
    Furdek, Marija
    KTH.
    Wosinska, Lena
    KTH.
    Agile optical networking: Beyond filtered solutions2018In: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Conference paper (Refereed)
    Abstract [en]

    Filterless optical networks based on broadcast-and-select nodes and coherent transceivers are attractive cost-effective and flexible solutions in core networks. In this paper, we explore the suitability of filterless architectures in metropolitan core and aggregation networks.

  • 2998.
    Tremblay, Christine
    et al.
    Ecole Technol Super, Network Technol Lab, Montreal, PQ, Canada..
    Archambault, Emile
    Ecole Technol Super, Network Technol Lab, Montreal, PQ, Canada..
    Belanger, Michel P.
    Ciena Corp, Ottawa, ON, Canada..
    Littlewood, Paul
    Ciena Corp, Ottawa, ON, Canada..
    Clelland, William
    Ciena Corp, Ottawa, ON, Canada..
    Furdek, Marija
    KTH.
    Wosinska, Lena
    KTH. KTH Royal Inst Technol, Stockholm, Sweden..
    Agile Optical Networking: Beyond Filtered Solutions2018In: 2018 Optical Fiber Communications Conference and Exposition, OFC 2018 - Proceedings, IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    Filterless optical networks based on broadcast-and-select nodes and coherent transceivers are attractive cost-effective and flexible solutions in core networks. In this paper, we explore the suitability of filterless architectures in metropolitan core and aggregation networks.

  • 2999. Tremblay, Christine
    et al.
    Littlewood, Paul
    Belanger, Michel P.
    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).
    Agile Filterless Optical Networking2017In: 2017 21st International Conference on Optical Network Design and Modeling, ONDM 2017 - Conference Proceedings, IEEE, 2017, article id 7958526Conference paper (Refereed)
    Abstract [en]

    Filterless optical networks based on broadcast-and-select nodes equipped with coherent transceivers can be considered as very attractive solutions for cost-effective and flexible capacity allocation in terrestrial and submarine applications. In this paper, we present an overview of the research on filterless optical networking in the last 10 years.

  • 3000. Tremblay, Christine
    et al.
    Xu, Zhenyu
    Archambault, Emile
    Mantelet, Guillaume
    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).
    Belanger, Michel P.
    Littlewood, Paul
    Proposed filterless architecture and control plane for emerging flexible coherent networks2013In: ICTON 2013: 15th International Conference on Transparent Optical Networks, 2013, p. 1-1Conference paper (Refereed)
    Abstract [en]

    Recent developments in coherent modem performance and digital signal processing (DSP) technologies have opened the opportunity for new agile network architectures [1, 2]. The filterless network concept has been proposed in [3] and it is shown that they are more cost-effective and reliable compared to active optical switching networks. Filterless optical networks use broadcast-and-select techniques in which passive non-filtered optical splitters and combiners are used for channel add-drop and fiber link interconnection. Furthermore, DSP-based coherent modems are complementary foundational technologies for flexible optical networking owing to their properties of dynamic impairment compensation, performance monitoring and tuneability. The resulting network architecture makes an attractive candidate solution for flexible optical networking [4]. In this talk, we review the recent progress in filterless optical network design and control [5]ᅵ[7]. In the first part, filterless architectural solutions are proposed for different network topologies and compared to active photonic switching solutions. A cost and performance analysis of filterless network solutions with 1 + 1 optical layer protection is also presented. In the second part, we present a control plane for filterless optical networks and describe its main characteristics through a performance study. Our results show that passive filterless networks can be considered as a cost effective and simpler alternative to active optical switching networks whenever traffic loading is not approaching full network capacity.

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