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  • 151.
    Pacifico, Davide
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Pacifico, Matteo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Hjalmarsson, Håkan
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Improving TCP Performance During the Intra LTE Handover2009In: GLOBECOM 2009 - 2009 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE, VOLS 1-8, 2009, p. 5343-5350Conference paper (Refereed)
    Abstract [en]

    Ensuring a seamless connection when users are moving across radio cells is essential to guarantee a high communication quality. In this paper, performance of TCP during the handover in a Long Term Evolution (LTE) network is investigated. Specifically, mobile users with high bit rates TCP services are considered, and the impacts of the intra LTE handover over their perceived throughput are studied. Due to the mobility of the users across radio cells, the high bandwidth required, and possible network congestions, it is shown that the handover may cause sudden degradation of the quality of the communication if the process is not correctly controlled. To alleviate these problems, three solutions are proposed: fast path switch, handover prediction, and active queue management. The first two solutions avoids excessive delay in the packet delivery during the handover, whereas the second solution acts at the transport network with an active queue management. Simulation results, obtained by an extension of the ns-2 simulator, show that the proposed solutions present advantages, and that the handover prediction used with the active queue management increases TCP performance significantly.

  • 152. Park, P.
    et al.
    Ergen, S. C.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Sangiovanni-Vincentelli, A.
    Duty-cycle optimization for IEEE 802.15.4 wireless sensor networks2013In: ACM Transactions on Sensor Networks, ISSN 1550-4859, Vol. 10, no 1, p. 12-Article in journal (Refereed)
    Abstract [en]

    Most applications of wireless sensor networks require reliable and timely data communication with maximum possible network lifetime under low traffic regime. These requirements are very critical especially for the stability of wireless sensor and actuator networks. Designing a protocol that satisfies these requirements in a network consisting of sensor nodes with traffic pattern and location varying over time and space is a challenging task. We propose an adaptive optimal duty-cycle algorithm running on top of the IEEE 802.15.4 medium access control tominimize power consumption while meeting the reliability and delay requirements. Such a problem is complicated because simple and accurate models of the effects of the duty cycle on reliability, delay, and power consumption are not available. Moreover, the scarce computational resources of the devices and the lack of prior information about the topology make it impossible to compute the optimal parameters of the protocols. Based on an experimental implementation, we propose simple experimental models to expose the dependency of reliability, delay, and power consumption on the duty cycle at the node and validate it through extensive experiments. The coefficients of the experimental-based models can be easily computed on existing IEEE 802.15.4 hardware platforms by introducing a learning phase without any explicit information about data traffic, network topology, and medium access control parameters. The experimental-based model is then used to derive a distributed adaptive algorithm for minimizing the power consumption while meeting the reliability and delay requirements in the packet transmission. The algorithm is easily implementable on top of the IEEE 802.15.4 medium access control without any modifications of the protocol. An experimental implementation of the distributed adaptive algorithm on a test bed with off-the-shelf wireless sensor devices is presented. The experimental performance of the algorithms is compared to the existing solutions from the literature. The experimental results show that the experimentalbased model is accurate and that the proposed adaptive algorithm attains the optimal value of the duty cycle, maximizing the lifetime of the network while meeting the reliability and delay constraints under both stationary and transient conditions. Specifically, even if the number of devices and their traffic configuration change sharply, the proposed adaptive algorithm allows the network to operate close to its optimal value. Furthermore, for Poisson arrivals, the duty-cycle protocol is modeled as a finite capacity queuing system in a star network. This simple analytical model provides insights into the performance metrics, including the reliability, average delay, and average power consumption of the duty-cycle protocol.

  • 153.
    Park, Pan Gun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Di Marco, Piergiuseppe
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Soldati, Pablo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    A generalized Markov chain model for effective analysis of slotted IEEE 802.15.42009In: 2009 IEEE 6th International Conference on Mobile Adhoc and Sensor Systems, 2009, Vol. MASS '09, p. 130-139Conference paper (Refereed)
    Abstract [en]

    A generalized analysis of the IEEE 802.15.4 medium access control (MAC) protocol in terms of reliability, delay and energy consumption is presented. The IEEE 802.15.4 exponential backoff process is modeled through a Markov chain taking into account retry limits, acknowledgements, and unsaturated traffic. Simple and effective approximations of the reliability, delay and energy consumption under low traffic regime are proposed. It is demonstrated that the delay distribution of IEEE 802.15.4 depends mainly on MAC parameters and collision probability. In addition, the impact of MAC parameters on the performance metrics is analyzed. The analysis is more general and gives more accurate results than existing methods in the literature. Monte Carlo simulations confirm that the proposed approximations offer a satisfactory accuracy.

  • 154.
    Park, Pan Gun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Automatic Control.
    Bonivento, A.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Sangiovanni-Vincentelli, A.
    Breath: A self-adapting protocol for wireless sensor networks in control and automation2008In: 2008 5th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks, 2008, Vol. SECON, p. 323-331Conference paper (Refereed)
    Abstract [en]

    The novel cross-layer protocol Breath for wireless sensor networks is designed, implemented, and experimentally evaluated. The Breath protocol is based on randomized routing, MAC and duty-cycling, which allow it to minimize the energy consumption of the network while ensuring a desired packet delivery end-to-end reliability and delay. The system model includes a set of source nodes that transmit packets via multi-hop communication to the destination. A constrained optimization problem, for which the objective function is the network energy consumption and the constraints are the packet latency and reliability, is posed and solved. It is shown that the communication layers can be jointly optimized for energy efficiency. The optimal working point of the network is achieved with a simple algorithm, which adapts to traffic variations with negligible overhead. The protocol was implemented on a test-bed with off-the-shelf wireless sensor nodes. It is compared with a standard IEEE 802.15.4 solution. Experimental results show that Breath meets the latency and reliability requirements, and that it exhibits a good distribution of the working load, thus ensuring a long lifetime of the network.

  • 155.
    Park, Pan Gun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Adaptive IEEE 802.15.4 medium access control protocol for control and monitoring applications2011In: Wireless Networking Based Control / [ed] Sudip K. Mazumder, Springer Science+Business Media B.V., 2011, p. 271-300Chapter in book (Refereed)
    Abstract [en]

    The IEEE 802.15.4 standard for wireless sensor networks (WSNs) can support energy efficient, reliable, and timely packet transmission by tuning the medium access control (MAC) parameters macMinBE; macMaxCSMABackoffs, and macMaxFrameRetries. Such a tuning is difficult, because simple and accurate models of the influence of these parameters on the probability of successful packet transmission, packet delay, and energy consumption are not available. Moreover, it is not clear how to adapt the parameters to the changes of the network and traffic regimes by algorithms that can run on resource-constrained nodes. In this chapter, a generalizedMarkov chain is proposed to model these relations by simple expressions without giving up the accuracy. In contrast to previous work, the presence of limited number of retransmissions, acknowledgments, unsaturated traffic, and packet size is accounted for. The model is then used to derive an adaptive algorithm forminimizing the power consumptionwhile guaranteeing reliability and delay constraints in the packet transmission. The algorithm does not require any modification of the IEEE 802.15.4 standard and can be easily implemented on network nodes. Numerical results show that the analysis is accurate and that the proposed algorithm satisfies reliability and delay constraints, and ensures a longer lifetime of the network under both stationary and transient network conditions.

  • 156.
    Park, Pan Gun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    Berkeley, CA,USA.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Experimental evaluation of power control algorithms for wireless sensor networks2008In: Proceedings of the 17th World Congress The International Federation of Automatic Control Seoul, Korea, July 6-11, 2008, 2008Conference paper (Refereed)
    Abstract [en]

    The main contribution of this paper is the implementation and experimental evaluation of thee radio power control algorithms for wireless sensor networks. We illustrate the necessity of lightweight radio power control algorithms for the deployment of wireless sensor networks in realistic situations. Furthermore, based on a simple loss model, we develop an algorithm that optimizes the transmit power while guaranteeing a desired packet error probability. The simple power control strategy is also compared with two other strategies in experiments using Tmote Sky sensor nodes. A component-based software implementation in the Contiki operating system is used.

  • 157.
    Park, Pan Gun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Performance analysis of GTS allocation in Beacon Enabled IEEE 802.15.42009In: 2009 6TH ANNUAL IEEE COMMUNICATIONS SOCIETY CONFERENCE ON SENSOR, MESH AND AD HOC COMMUNICATIONS AND NETWORKS (SECON 2009), NEW YORK: IEEE , 2009, p. 431-439Conference paper (Refereed)
    Abstract [en]

    Time-critical applications for wireless sensor networks (WSNs) are an important class of services supported by the standard IEEE 802.15.4. Control, actuation, and monitoring are all examples of applications where information must be delivered within some deadline. Understanding the delay in the packet delivery is fundamental to assess performance limitation for the standard. In this paper we analyze the guaranteed time slot (GTS) allocation mechanism used in IEEE 802.15.4 networks for time-critical applications. Specifically, we propose a Markov chain to model the stability, delay, and throughput of GTS allocation. We analyze the impact of the protocol parameters on these performance indexes. Monte Carlo simulations show that the theoretical analysis is quite accurate. Thus, our analysis can be used to design efficient GTS allocation for IEEE 802.15.4.

  • 158.
    Park, Pangun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Di Marco, Piergiuseppe
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Delay distribution analysis of wireless personal area networks2012In: IEEE 51st Annual Conference on Decision and Control (CDC), 2012, IEEE conference proceedings, 2012, p. 5864-5869Conference paper (Refereed)
    Abstract [en]

    Characterizing the network delay distribution is a fundamental step to properly compensate the delay of Networked Control Systems (NCSs). Due to the random backoff mechanism employed by Wireless Personal Area Network (WPAN) protocols, it is difficult to derive such a distribution. In this paper, the probability distribution of the delay for successfully received packets in WPANs is characterized. The analysis uses a moment generating function method based on an extended Markov chain model. The model considers the exponential backoff process with retry limits, acknowledgements, unsaturated traffic, and variable packet size, and gives an accurate explicit expression of the probability distribution of the network delay. The probability distribution of the delay is a function of the traffic load, number of nodes, and parameters of the communication protocol. Monte Carlo simulations validate the analysis for different network and protocol parameters. We show that the probability distribution of the delay is significantly different from existing network models used for NCS design. Furthermore, the parameters of the communication protocol result to be critical to stabilize control systems.

  • 159.
    Park, Pangun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Di Marco, Piergiuseppe
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Modeling and optimization of the IEEE 802.15.4 protocol for reliable and timely communications2013In: IEEE Transactions on Parallel and Distributed Systems, ISSN 1045-9219, E-ISSN 1558-2183, Vol. 24, no 3, p. 550-564Article in journal (Refereed)
    Abstract [en]

    Distributed processing through ad hoc and sensor networks is having a major impact on scale and applications of computing. The creation of new cyber-physical services based on wireless sensor devices relies heavily on how well communication protocols can be adapted and optimized to meet quality constraints under limited energy resources. The IEEE 802.15.4 medium access control protocol for wireless sensor networks can support energy efficient, reliable, and timely packet transmission by a parallel and distributed tuning of the medium access control parameters. Such a tuning is difficult, because simple and accurate models of the influence of these parameters on the probability of successful packet transmission, packet delay, and energy consumption are not available. Moreover, it is not clear how to adapt the parameters to the changes of the network and traffic regimes by algorithms that can run on resource-constrained devices. In this paper, a Markov chain is proposed to model these relations by simple expressions without giving up the accuracy. In contrast to previous work, the presence of limited number of retransmissions, acknowledgments, unsaturated traffic, packet size, and packet copying delay due to hardware limitations is accounted for. The model is then used to derive a distributed adaptive algorithm for minimizing the power consumption while guaranteeing a given successful packet reception probability and delay constraints in the packet transmission. The algorithm does not require any modification of the IEEE 802.15.4 medium access control and can be easily implemented on network devices. The algorithm has been experimentally implemented and evaluated on a testbed with off-the-shelf wireless sensor devices. Experimental results show that the analysis is accurate, that the proposed algorithm satisfies reliability and delay constraints, and that the approach reduces the energy consumption of the network under both stationary and transient conditions. Specif- cally, even if the number of devices and traffic configuration change sharply, the proposed parallel and distributed algorithm allows the system to operate close to its optimal state by estimating the busy channel and channel access probabilities. Furthermore, results indicate that the protocol reacts promptly to errors in the estimation of the number of devices and in the traffic load that can appear due to device mobility. It is also shown that the effect of imperfect channel and carrier sensing on system performance heavily depends on the traffic load and limited range of the protocol parameters.

  • 160.
    Park, Pangun
    et al.
    Chungnam Natl Univ, Dept Radio & Informat Commun Engn, Daejeon 305764, South Korea..
    Ergen, Sinem Coleri
    Koc Univ, Dept Elect & Elect Engn, TR-34450 Istanbul, Turkey..
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Lu, Chenyang
    Washington Univ, Dept Comp Sci & Engn, St Louis, MO 63130 USA..
    Johansson, Karl H.
    KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Wireless Network Design for Control Systems: A Survey2018In: IEEE Communications Surveys and Tutorials, ISSN 1553-877X, E-ISSN 1553-877X, Vol. 20, no 2, p. 978-1013Article in journal (Refereed)
    Abstract [en]

    Wireless networked control systems (WNCSs) are composed of spatially distributed sensors, actuators, and controllers communicating through wireless networks instead of conventional point-to-point wired connections. Due to their main benefits in the reduction of deployment and maintenance costs, large flexibility and possible enhancement of safety, WNCS are becoming a fundamental infrastructure technology for critical control systems in automotive electrical systems, avionics control systems, building management systems, and industrial automation systems. The main challenge in WNCS is to jointly design the communication and control systems considering their tight interaction to improve the control performance and the network lifetime. In this survey, we make an exhaustive review of the literature on wireless network design and optimization for WNCS. First, we discuss what we call the critical interactive variables including sampling period, message delay, message dropout, and network energy consumption. The mutual effects of these communication and control variables motivate their joint tuning. We discuss the analysis and design of control systems taking into account the effect of the interactive variables on the control system performance. Moreover, we discuss the effect of controllable wireless network parameters at all layers of the communication protocols on the probability distribution of these interactive variables. We also review the current wireless network standardization for WNCS and their corresponding methodology for adapting the network parameters. Finally, we present the state-of-the-art wireless network design and optimization for WNCS, while highlighting the tradeoff between the achievable performance and complexity of various approaches. We conclude the survey by highlighting major research issues and identifying future research directions.

  • 161.
    Park, Pangun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Bonivento, Alvise
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Sangiovanni-Vincentelli, Alberto L.
    Breath: an Adaptive Protocol for Industrial Control Applications using Wireless Sensor Networks2011In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 10, no 6, p. 821-838Article in journal (Refereed)
    Abstract [en]

    An energy-efficient, reliable and timely data transmission is essential for Wireless Sensor Networks (WSNs) employed in scenarios where plant information must be available for control applications. To reach a maximum efficiency, cross-layer interaction is a major design paradigm to exploit the complex interaction among the layers of the protocol stack. This is challenging because latency, reliability, and energy are at odds, and resource-constrained nodes support only simple algorithms. In this paper, the novel protocol Breath is proposed for control applications. Breath is designed for WSNs where nodes attached to plants must transmit information via multihop routing to a sink. Breath ensures a desired packet delivery and delay probabilities while minimizing the energy consumption of the network. The protocol is based on randomized routing, medium access control, and duty-cycling jointly optimized for energy efficiency. The design approach relies on a constrained optimization problem, whereby the objective function is the energy consumption and the constraints are the packet reliability and delay. The challenging part is the modeling of the interactions among the layers by simple expressions of adequate accuracy, which are then used for the optimization by in-network processing. The optimal working point of the protocol is achieved by a simple algorithm, which adapts to traffic variations and channel conditions with negligible overhead. The protocol has been implemented and experimentally evaluated on a testbed with off-the-shelf wireless sensor nodes, and it has been compared with a standard IEEE 802.15.4 solution. Analytical and experimental results show that Breath is tunable and meets reliability and delay requirements. Breath exhibits a good distribution of the working load, thus ensuring a long lifetime of the network. Therefore, Breath is a good candidate for efficient, reliable, and timely data gathering for control applications.

  • 162.
    Park, Pangun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Adaptive IEEE 802.15.4 protocol for energy efficient, reliable and timely communications2010In: Proceedings of the 9th ACM/IEEE International Conference on Information Processing in Sensor Networks, New York: ACM , 2010, p. 327-338Conference paper (Refereed)
    Abstract [en]

    The IEEE 802.15.4 standard for wireless sensor networks can support energy efficient, reliable, and timely packet transmission by tuning the medium access control parameters macMinBE, macMax-CSMABackoffs, and macMaxFrameRetries. Such a tuning is difficult, because simple and accurate models of the influence of these parameters on the probability of successful packet transmission, packet delay and energy consumption are not available. Moreover, it is not clear how to adapt the parameters to the changes of the network and traffic regimes by algorithms that can run on resource-constrained nodes. In this paper, an effective analytical model is used to derive an adaptive algorithm at the medium access control layer for minimizing the power consumption while guaranteeing reliability and delay constraints in the packet transmission. The algorithm does not require any modifications of the IEEE 802.15.4 standard and can be easily implemented on existing network nodes. Numerical results show that the analysis is accurate, that the proposed algorithm satisfies reliability and delay constraints, and ensures a longer lifetime of the network under both stationary and transient network conditions.

  • 163.
    Park, Pangun
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Modeling and Stability Analysis of Hybrid Multiple Access in the IEEE 802.15.4 Protocol2013In: ACM Transactions on Sensor Networks, ISSN 1550-4859, Vol. 9, no 2, p. 13-Article in journal (Refereed)
    Abstract [en]

    To offer flexible quality of service to several classes of applications, the medium access control (MAC) protocol of IEEE 802.15.4 wireless sensor networks (WSNs) combines the advantages of a random access with contention with a time division multiple access (TDMA) without contention. Understanding reliability, delay, and throughput is essential to characterizing the fundamental limitations of the MAC and optimizing its parameters. Nevertheless, there is not yet a clear investigation of the achievable performance of hybrid MAC. In this article, an analytical framework for modeling the behavior of the hybrid MAC protocol of the IEEE 802.15.4 standard is proposed. The main challenge for an accurate analysis is the coexistence of the stochastic behavior of the random access and the deterministic behavior of the TDMA scheme. The analysis is done in three steps. First, the contention access scheme of the IEEE 802.15.4 exponential back-off process is modeled through an extended Markov chain that takes into account channel, retry limits, acknowledgements, unsaturated traffic, and superframe period. Second, the behavior of the TDMA access scheme is modeled by another Markov chain. Finally, the two chains are coupled to obtain a complete model of the hybrid MAC. By using this model, the network performance in terms of reliability, average packet delay, average queuing delay, and throughput is evaluated through both theoretical analysis and experiments. The protocol has been implemented and evaluated on a testbed with off-the-shelf wireless sensor devices to demonstrate the utility of the analysis in a practical setup. It is established that the probability density function of the number of received packets per superframe follows a Poisson distribution. It is determined under which conditions the guaranteed time slot allocation mechanism of IEEE 802.15.4 is stable. It is shown that the mutual effect between throughput of the random access and the TDMA scheme for a fixed superframe length is critical to maximizing the overall throughput of the hybrid MAC. In high traffic load, the throughput of the random access mechanism dominates over TDMA due to the constrained use of TDMA in the standard. Furthermore, it is shown that the effect of imperfect channels and carrier sensing on system performance heavily depends on the traffic load and limited range of the protocol parameters. Finally, it is argued that the traffic generation model established in this article may be used to design an activation timer mechanism in a modified version of the CSMA/CA algorithm that guarantees a stable network performance.

  • 164. Rinaldi, C.
    et al.
    Santucci, F.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Hybrid model of least squares handover algorithms in wireless networks2007In: IEEE Vehicular Technology Conference, 2007, p. 3106-3110Conference paper (Refereed)
    Abstract [en]

    An adaptive handover algorithm for wireless communication systems is addressed in this paper. Moving from the Generalized Extended Least Square handover algorithm proposed in [1], we model the handover mechanism as a hybrid system, and we include it in a dynamic optimization problem which is solved through the use of a trellis diagram. The objective function takes into account the parameters that influence the handover mechanism. The optimal solution of the program allows to evaluate performance of the handover in terms of the probability of handover and probability of outage.

  • 165.
    Rossitto, Chiara
    et al.
    Stockholm Univ, Dept Comp & Syst Sci, Stockholm, Sweden..
    Rostami, Asreen
    Stockholm Univ, Dept Comp & Syst Sci, Stockholm, Sweden..
    Tholander, Jakob
    Stockholm Univ, Dept Comp & Syst Sci, Stockholm, Sweden..
    McMillan, Donald
    Stockholm Univ, Dept Comp & Syst Sci, Stockholm, Sweden..
    Barkhuus, Louise
    IT Univ Copenhagen, Dept Digital Design, Copenhagen, Denmark..
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Turchet, Luca
    Queen Mary Univ London, Sch Elect Engn & Comp Sci, London, England.;MIND Mus Labs, Stockholm, Sweden..
    Musicians' Initial Encounters with a Smart Guitar2018In: NORDICHI'18: PROCEEDINGS OF THE 10TH NORDIC CONFERENCE ON HUMAN-COMPUTER INTERACTION, Association for Computing Machinery (ACM), 2018, p. 13-24Conference paper (Refereed)
    Abstract [en]

    This paper presents a case study of a fully working prototype of the Sensus smart guitar. Eleven professional guitar players were interviewed after a prototype test session. The smartness of the guitar was perceived as enabling the integration of a range of equipment into a single device, and the proactive exploration of novel expressions. The results draw attention to the musicians' sense-making of the smart qualities, and to the perceived impact on their artistic practices. The themes highlight how smartness was experienced in relation to the guitar's agency and the skills it requires, the tension between explicit (e.g. playing a string) and implicit (e.g. keeping rhythm) body movements, and to performing and producing music. Understanding this felt sense of smartness is relevant to how contemporary HCI research conceptualizes mundane artefacts enhanced with smart technologies, and to how such discourse can inform related design issues.

  • 166.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Boccardi, F.
    Erkip, E.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fodor, Gabor
    KTH, School of Electrical Engineering (EES), Automatic Control. Ericsson Research.
    Kountouris, Marios
    Popovski, Petar
    Zorzi, Michele
    The Impact of beamforming and coordination on spectrum pooling in mmWave Cellular networks2016In: Signals, Systems and Computers, 2016 50th Asilomar Conference on, Institute of Electrical and Electronics Engineers (IEEE), 2016, article id 7868986Conference paper (Refereed)
    Abstract [en]

    Spectrum pooling is not typically used in current cellular networks, because it only provides a slight performance improvement while requiring heavy coordination among different cellular operators. However, these problems can be potentially overcome in millimeter-wave (mmWave) networks, thanks to the use of beamforming both at base stations and at user equipments. In this paper, we develop a joint beamforming and cell association optimization problem to characterize the performance gain that can be obtained when spectrum pooling is used, as a function of the underlying beamforming and coordination strategies. Our performance analysis reveals that beamforming can substantially reduce the need for coordination and simplify the implementation of spectrum pooling. These benefits are more prominent at higher mmWave frequencies (for example, 73 GHz) due to the possibility of having antenna arrays with more elements within the radome. The results of this paper provides useful insights on the feasibility of spectrum pooling at mmWave networks.

  • 167.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Boccardi, Federico
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fodor, Gabor
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Zorzi, Michele
    Spectrum Sharing in mmWave Cellular Networks via Cell Association, Coordination, and Beamforming2016In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 34, no 11, p. 2902-2917Article in journal (Refereed)
    Abstract [en]

    This paper investigates the extent to which spectrum sharing in millimeter-wave (mmWave) networks with multiple cellular operators is a viable alternative to traditional dedicated spectrum allocation. Specifically, we develop a general mathematical framework to characterize the performance gain that can be obtained when spectrum sharing is used, as a function of the underlying beamforming, operator coordination, bandwidth, and infrastructure sharing scenarios. The framework is based on joint beamforming and cell association optimization, with the objective of maximizing the long-term throughput of the users. Our asymptotic and non-asymptotic performance analyses reveal five key points: 1) spectrum sharing with light on-demand intra-and inter-operator coordination is feasible, especially at higher mmWave frequencies (for example, 73 GHz); 2) directional communications at the user equipment substantially alleviate the potential disadvantages of spectrum sharing (such as higher multiuser interference); 3) large numbers of antenna elements can reduce the need for coordination and simplify the implementation of spectrum sharing; 4) while inter-operator coordination can be neglected in the large-antenna regime, intra-operator coordination can still bring gains by balancing the network load; and 5) critical control signals among base stations, operators, and user equipment should be protected from the adverse effects of spectrum sharing, for example by means of exclusive resource allocation. The results of this paper, and their extensions obtained by relaxing some ideal assumptions, can provide important insights for future standardization and spectrum policy.

  • 168.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Analysis and optimization of random sensing order in cognitive radio networks2014In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 33, no 5, p. 803-819Article in journal (Refereed)
    Abstract [en]

    Developing an efficient spectrum access policy enables cognitive radios to dramatically increase spectrum utilization while ensuring predetermined quality of service levels for primary users. In this paper, modeling, performance analysis, and optimization of a distributed secondary network with random sensing order policy are studied. Specifically, the secondary users create a random order of available channels upon primary users return, and then find optimal transmission and handoff opportunities in a distributed manner. By a Markov chain analysis, the average throughputs of the secondary users and average interference level among the secondary and primary users are investigated. A maximization of the secondary network performance in terms of the throughput while keeping under control the average interference is proposed. It is shown that despite of traditional view, non-zero false alarm in the channel sensing can increase channel utilization, especially in a dense secondary network where the contention is too high. Then, two simple and practical adaptive algorithms are established to optimize the network. The second algorithm follows the variations of the wireless channels in non-stationary conditions and outperforms even static brute force optimization, while demanding few computations. The convergence of the distributed algorithms are theoretically investigated based on the analytical performance indicators established by the Markov chain analysis. Finally, numerical results validate the analytical derivations and demonstrate the efficiency of the proposed schemes. It is concluded that fully distributed sensing order algorithms can lead to substantial performance improvements in cognitive radio networks without the need of centralized management or message passing among the users.

  • 169.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Analysis and Optimization of Random Sensing Order in Cognitive Radio Systems2013Conference paper (Other academic)
    Abstract [en]

    Developing an efficient spectrum access policy enables cognitive radios to dramatically increase spectrum utilization while assuring predetermined quality of service levels for the primary users. In this letter, modeling, performance analysis, and optimization of a distributed secondary network with random sensing order policy are studied. Specifically, the secondary users create a random order of the available channels to sense and find a transmission opportunity in a distributed manner. For this network, the average throughputs of the secondary users and average interference level between the secondary and primary users are evaluated by a new Markov model. Then, a maximization of the secondary network performance in terms of throughput while keeping under control the average interference is proposed. Then, a simple and practical adaptive algorithm is developed to optimize the network in a distributed manner. Interestingly, the proposed algorithm follows the variations of the wireless channels in non-stationary conditions and besides having substantially lower computational cost, it outperforms static brute force optimization. Finally, numerical results are provided to demonstrate the efficiencies of the proposed schemes. It is shown that fully distributed algorithms can achieve substantial performance improvements in cognitive radio networks without the need of centralized management or message passing among the users.

  • 170.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Distributed random sensing order analysis and optimization in cognitive radio systems2014In: 2014 IEEE International Conference on Communications, ICC 2014, IEEE Communications Society, 2014, p. 1543-1548Conference paper (Refereed)
    Abstract [en]

    Developing an efficient spectrum access policy enables cognitive radios to dramatically increase spectrum utilization while assuring predetermined quality of service levels for the primary users. In this paper, modeling, performance analysis, and optimization of a distributed secondary network with random sensing order policy are studied. Specifically, the secondary users create a random order of the available channels and then find a transmission opportunity in a distributed manner. By a Markov chain analysis, the average throughputs of the secondary users and average interference level between the secondary and primary users are evaluated. Then, a maximization of the performance of the secondary network in terms of throughput while keeping under control the average interference is proposed. A simple and practical adaptive algorithm is established to optimize the network. Finally, numerical results are provided to validate the analytical derivations and demonstrate the performance of the proposed schemes. It is shown that distributed algorithms can achieve substantial performance improvements in cognitive radio networks without the need of centralized operations or management. 

  • 171.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    Millimeter wave ad hoc networks: Noise-limited or interference-limited?2015Conference paper (Refereed)
    Abstract [en]

    In millimeter wave (mmWave) communication systems,narrow beam operations overcome severe channel attenuations,reduce multiuser interference, and thus introduce thenew concept of noise-limited mmWave wireless networks. Theregime of the network, whether noise-limited or interferencelimited,heavily reflects on the medium access control (MAC)layer throughput and on proper resource allocation and interferencemanagement strategies. Yet, alternating presence of theseregimes and, more importantly, their dependence on the mmWavedesign parameters are ignored in the current approaches tommWave MAC layer design, with the potential disastrous consequenceson the throughput/delay performance. In this paper,tractable closed-form expressions for collision probability andMAC layer throughput of mmWave networks, operating underslotted ALOHA and TDMA, are derived. The new analysis revealsthat mmWave networks may exhibit a non negligible transitionalbehavior from a noise-limited regime to an interference-limitedregime, depending on the density of the transmitters, densityand size of obstacles, transmission probability, beamwidth, andtransmit power. It is concluded that a new framework of adaptivehybrid resource allocation procedure, containing a proactivecontention-based phase followed by a reactive contention-free onewith dynamic phase duration, is necessary to cope with suchtransitional behavior.

  • 172.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Random Sensing Order in Cognitive Radio Systems: Performance Evaluation and Optimization2014In: Proc. IEEE Infocom Workshop, IEEE conference proceedings, 2014, p. 201-202Conference paper (Refereed)
    Abstract [en]

    Developing an efficient spectrum access policy enables cognitive radios to dramatically increase spectrum utilization while assuring predetermined quality of service levels for the primary users. In this abstract, modeling, performance evaluation, and optimization of a distributed secondary network with random sensing order policy are studied. Specifically, the secondary users create a random order of the available channels upon primary users return, and then find an optimal transmission opportunity in a distributed manner. After modeling the behavior of the SUs by a Markov chain, the average throughputs of the secondary users and interference level among the secondary and primary users are evaluated. Then, a maximization of the secondary network performance in terms of throughput while keeping under control the average interference is proposed. A simple and practical adaptive algorithm is developed to optimize the network. Interestingly, the proposed algorithm follows the variations of the wireless channels in non-stationary conditions and outperforms even static brute force optimization, while demanding few computations. Finally, numerical results are provided to demonstrate the efficiencies of the proposed schemes. It is shown that fully distributed algorithms can achieve substantial performance improvements in cognitive radio networks without the need of centralized management or message passing among the users.

  • 173.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    The Transitional Behavior of Interference in Millimeter Wave NetworksManuscript (preprint) (Other academic)
  • 174.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    The Transitional Behavior of Interference in Millimeter Wave Networks and Its Impact on Medium Access Control2015In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 64, no 2, p. 723-740Article in journal (Refereed)
    Abstract [en]

    Millimeter wave (mmWave) communication systems use large number of antenna elements that can potentially overcome severe channel attenuation by narrow beamforming. Narrow-beam operation in mmWave networks also reduces multiuser interference, introducing the concept of noise-limited wireless networks as opposed to interference-limited ones. The noise-limited or interference-limited regime heavily reflects on the medium access control (MAC) layer throughput and on proper resource allocation and interference management strategies. Yet, these regimes are ignored in current approaches to mmWave MAC layer design, with the potential disastrous consequences on the communication performance. In this paper, we investigate these regimes in terms of collision probability and throughput. We derive tractable closed-form expressions for the collision probability and MAC layer throughput of mmWave ad hoc networks, operating under slotted ALOHA. The new analysis reveals that mmWave networks may exhibit a non-negligible transitional behavior from a noise-limited regime to an interference-limited one, depending on the density of the transmitters, density and size of obstacles, transmission probability, operating beamwidth, and transmission power. Such transitional behavior necessitates a new framework of adaptive hybrid resource allocation procedure, containing both contention-based and contention-free phases with on-demand realization of the contention-free phase. Moreover, the conventional collision avoidance procedure in the contention-based phase should be revisited, due to the transitional behavior of interference, to maximize throughput/delay performance of mmWave networks. We conclude that, unless proper hybrid schemes are investigated, the severity of the transitional behavior may significantly reduce throughput/delay performance of mmWave networks.

  • 175.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fodor, Gabor
    KTH, School of Electrical Engineering (EES), Automatic Control. Ericsson Res, Sweden.
    Popovski, Petar
    Aalborg Univ, Denmark.
    Zorzi, Michele
    Univ Padua, Italy.
    Millimeter Wave Cellular Networks: A MAC Layer Perspective2015In: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 63, no 10, p. 3437-3458Article in journal (Refereed)
    Abstract [en]

    The millimeter wave (mmWave) frequency band is seen as a key enabler of multi-gigabit wireless access in future cellular networks. In order to overcome the propagation challenges, mmWave systems use a large number of antenna elements both at the base station and at the user equipment, which lead to high directivity gains, fully-directional communications, and possible noise-limited operations. The fundamental differences between mmWave networks and traditional ones challenge the classical design constraints, objectives, and available degrees of freedom. This paper addresses the implications that highly directional communication has on the design of an efficient medium access control (MAC) layer. The paper discusses key MAC layer issues, such as synchronization, random access, handover, channelization, interference management, scheduling, and association. The paper provides an integrated view on MAC layer issues for cellular networks, identifies new challenges and tradeoffs, and provides novel insights and solution approaches.

  • 176.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Modiano, Eytan
    Interference Model Similarity Index and Its Applications to Millimeter-Wave Networks2018In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 17, no 1, p. 71-85Article in journal (Refereed)
    Abstract [en]

    In wireless communication networks, interference models are routinely used for tasks, such as performance analysis, optimization, and protocol design. These tasks are heavily affected by the accuracy and tractability of the interference models. Yet, quantifying the accuracy of these models remains a major challenge. In this paper, we propose a new index for assessing the accuracy of any interference model under any network scenario. Specifically, it is based on a new index that quantifies the ability of any interference model in correctly predicting harmful interference events, that is, link outages. We consider specific wireless scenario of both conventional sub-6 GHz and millimeter-wave networks and demonstrate how our index yields insights into the possibility of simplifying the set of dominant interferers, replacing a Nakagami or Rayleigh random fading by an equivalent deterministic channel, and ignoring antenna sidelobes. Our analysis reveals that in highly directional antenna settings with obstructions, even simple interference models (such as the classical protocol model) are accurate, while with omnidirectional antennas, more sophisticated and complex interference models (such as the classical physical model) are necessary. Our new approach makes it possible to adopt the simplest interference model of adequate accuracy for every wireless network.

  • 177.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Modiano, Eytan
    On the Accuracy of Interference Models in Wireless Communications2016In: 2016 IEEE International Conference on Communications, ICC 2016, Institute of Electrical and Electronics Engineers (IEEE), 2016, article id 7510904Conference paper (Refereed)
    Abstract [en]

    We develop a new framework for measuring and comparing the accuracy of any wireless interference models used in the analysis and design of wireless networks. Our approach is based on a new index that assesses the ability of the interference model to correctly predict harmful interference events, i.e., link outages. We use this new index to quantify the accuracy of various interference models used in the literature, under various scenarios such as Rayleigh fading wireless channels, directional antennas, and blockage (impenetrable obstacles) in the network. Our analysis reveals that in highly directional antenna settings with obstructions, even simple interference models (e.g., the classical protocol model) are accurate, while with omnidirectional antennas, more sophisticated and complex interference models (e.g., the classical physical model) are necessary. Our new approach makes it possible to adopt the appropriate interference model of adequate accuracy and simplicity in different settings.

  • 178.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Popovski, Petar
    Aalborg University, Denmark.
    Zorzi, Michele
    Design aspects of short range millimeter wave networks: A MAC layer perspective2016In: IEEE Network, ISSN 0890-8044, E-ISSN 1558-156X, Vol. 30, no 3, p. 88-96Article in journal (Refereed)
    Abstract [en]

    Increased density of wireless devices, ever growing demands for extremely high data rate, and spectrum scarcity at microwave bands make the millimeter wave (mmWave) frequencies an important player in future wireless networks. However, mmWave communication systems exhibit severe attenuation, blockage, deafness, and may need microwave networks for coordination and fall-back support. To compensate for high attenuation, mmWave systems exploit highly directional operation, which in turn substantially reduces the interference footprint. The significant differences between mmWave networks and legacy communication technologies challenge the classical design approaches, especially at the medium access control (MAC) layer, which has received comparatively less attention than PHY and propagation issues in the literature so far. In this paper, the MAC layer design aspects of shortrange mmWave networks are discussed. In particular, we explain why current mmWave standards fail to fully exploitthe potential advantages of short range mmWave technology, and argue for the necessity of new collision-awarehybrid resource allocation frameworks with on-demand control messages, the advantages of a collision notification message, and the potential of multihop communication to provide reliable mmWave connections.

  • 179.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Ghauch, Hadi
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Learning-based tracking of AoAs and AoDs in mmWave networks2018In: Proceedings of the Annual International Conference on Mobile Computing and Networking, MOBICOM, Association for Computing Machinery , 2018, p. 45-50Conference paper (Refereed)
    Abstract [en]

    This paper considers a millimeter-wave communication system and proposes an efficient channel estimation scheme with a minimum number of pilots. We model the dynamics of the channel’s second-order statistics by a Markov process and develop a learning framework to obtain these dynamics from an unlabeled set of measured angles of arrival and departure. We then find the optimal precoding and combining vectors for pilot signals. Using these vectors, the transmitter and receiver will sequentially estimate the corresponding angles of departure and arrival, and then refine the pilot precoding and combining vectors to minimize the error of estimating the channel gains.

  • 180.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Ghauch, Hadi
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering. COMELEC Department, Telecom ParisTech, Paris, France.
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Skoglund, Mikael
    KTH, School of Electrical Engineering and Computer Science (EECS), Information Science and Engineering.
    Learning and Data Selection in Big Datasets2019In: Proceedings of the 36th International Conference on MachineLearning, Long Beach, California, PMLR 97, 2019., 2019Conference paper (Refereed)
    Abstract [en]

    Finding a dataset of minimal cardinality to characterize the optimal parameters of a model is of paramount importance in machine learning and distributed optimization over a network. This paper investigates the compressibility of large datasets. More specifically, we propose a framework that jointly learns the input-output mapping as well as the most representative samples of the dataset (sufficient dataset). Our analytical results show that the cardinality of the sufficient dataset increases sub-linearly with respect to the original dataset size. Numerical evaluations of real datasets reveal a large compressibility, up to 95%, without a noticeable drop in the learnability performance, measured by the generalization error.

  • 181.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Gkatzikis, Lazaros
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Beam-searching and Transmission Scheduling in Millimeter Wave Communications2015In: 2015 IEEE International Conference on Communications (ICC), IEEE conference proceedings, 2015, Vol. 2015, p. 1292-1297Conference paper (Refereed)
    Abstract [en]

    Millimeter wave (mmWave) wireless networks relyon narrow beams to support multi-gigabit data rates. Nevertheless, the alignment of transmitter and receiver beams is a time consuming operation, which introduces an alignment-throughput tradeoff. A wider beamwidth reduces the alignment overhead,but leads also to reduced directivity gains. Moreover, existing mmWave standards schedule a single transmission in eachtime slot, although directional communications facilitate multiple concurrent transmissions. In this paper, a joint consideration ofthe problems of beamwidth selection and scheduling is proposed to maximize effective network throughput. The resulting optimization problem requires exact knowledge of network topology,which may not be available in practice. Therefore, two standard compliant approximation algorithms are developed, which relyon underestimation and overestimation of interference. The first one aims to maximize the reuse of available spectrum, whereas the second one is a more conservative approach that schedules together only links that cause no interference. Extensive performance analysis provides useful insights on the directionality level and the number of concurrent transmissions that should bepursued. Interestingly, extremely narrow beams are in general not optimal.

  • 182.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Glaropoulos, Ioannis
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fodor, Viktoria
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Dimou, Konstantinos
    Ericsson Research.
    Energy efficient spectrum sensing and handoff strategies in cognitive radio networks2013In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896Article in journal (Refereed)
    Abstract [en]

    The limited spectrum resources and dramatic growth of high data rate communications have motivated opportunistic spectrum access using the promising concept of cognitive radio networks. Although this concept has emerged primarily to enhance spectrum utilization, the importance of energy consumption poses new challenges, because energy efficiency and communication performance can be at odds. In this paper, the existing approaches to energy efficiency spectrum sensing and handoff are classified. The tradeoff between energy consumption and throughput is established as function of the numerous design parameters of cognitive radio networks, both in the case of local and of cooperative spectrum sensing. It is argued that a number of important aspects still needs to be researched, such as fairness, dynamic behavior, reactive and proactive schemes for energy efficiency.

  • 183.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Glaropoulos,, Ioannis
    Fodor, Viktoria
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Ephremides, Antony
    Green Sensing and Access: Energy-Throughput Trade-offs in Cognitive Networking2015In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 53, no 11, p. 199-207Article, book review (Refereed)
    Abstract [en]

    Limited spectrum resources and the dramatic growth of high data rate applications have motivated opportunistic spectrum access exploiting the promising concept of cognitive networks. Although this concept has emerged primarily to enhance spectrum utilization and to allow the coexistence of heterogeneous network technologies, the importance of energy consumption imposes additional challenges, because energy consumption and communication performance can be at odds. In this article the approaches for energy efficient spectrum sensing and spectrum handoff, fundamental building blocks of cognitive networks, are investigated. The trade-offs between energy consumption and throughput, under local as well as under cooperative sensing, are characterized. We also discuss the additional factors that need to be investigated to achieve energy efficient cognitive operation under various application requirements.

  • 184.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Xu, Yuzhe
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Gkatzikis, Lazaros
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control.
    User association and the alignment-throughput tradeoff in millimeter wave networks2015In: Research and Technologies for Society and Industry Leveraging a better tomorrow (RTSI), 2015 IEEE 1st International Forum on, IEEE Communications Society, 2015, p. 100-105Conference paper (Refereed)
    Abstract [en]

    Millimeter wave (mmWave) communication is apromising candidate for future extremely high data rate, wirelessnetworks. The main challenges of mmWave communications aredeafness (misalignment between the beams of the transmitterand receiver) and blockage (severe attenuation due to obstacles).Due to deafness, prior to link establishment between a clientand its access point, a time consuming alignment/beam trainingprocedure is necessary, whose complexity depends on the operatingbeamwidth. Addressing blockage may require a reassociationto non-blocked access points, which in turn imposes additionalalignment overhead. This paper introduces a unifying frameworkto maximize network throughput considering both deafness andblockage. A distributed auction-based solution is proposed, wherethe clients and access points act asynchronously to achieveoptimal association along with the optimal operating beamwidth.It is shown that the proposed algorithm provably converges toa solution that maximizes the aggregate network utility withina desired bound. Convergence time and performance boundsare derived in closed-forms. Numerical results confirm superiorthroughput performance of the proposed solution compared toexisting approaches, and highlight the existence of a tradeoffbetween alignment overhead and achievable throughput thataffects the optimal association.

  • 185.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Yaghoubi, Forough
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Analysis and optimization of centralized sequential channel sensing in cognitive radio networks2014In: European Wireless 2014; 20th European Wireless Conference; Proceedings of, VDE Verlag GmbH, 2014, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Effective spectrum sensing strategies enable cognitiveradios to enhance the spectrum efficiency. In this paper,modeling, performance analysis, and optimization of spectrum handoff in a centralized cognitive radio network are studied.More specifically, for a given sensing order, the average throughput of secondary users and average interference level among the secondary and primary users are evaluated for a cognitive radio network with only one secondary user. By aMarkov chain analysis, a network with multiple secondary users performing cooperative spectrum sensing is modeled, and the above performance metrics are derived. Then, a maximization ofthe secondary network performance in terms of throughput while keeping under control the average interference is formulated.Finally, numerical results validate the analytical derivations andshow that optimally tuning sensing time significantly enhancesthe performance of the spectrum handoff. Also, we observe that exploiting OR rule for cooperative spectrum sensing provides a higher average throughput compared to AND rule.

  • 186.
    Shokri-Ghadikolaei, Hossein
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Yang, Yanpeng
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Petrova, Marina
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Sung, Ki Won
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Radio Systems Laboratory (RS Lab).
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems Engineering.
    Fast and Reliable Initial Cell-search for mmWave Networks2018Conference paper (Refereed)
    Abstract [en]

    In millimeter-wave wireless networks, the use of narrow beams, required to compensate for the severe path-loss, complicates the cell-discovery and initial access. In this paper, we investigate the feasibility of random beam forming and enhanced exhaustive search for cell-discovery by analyzing the latency and detection failure probability in the control-plane and the user throughput in the data-plane. We show that, under realistic propagation model and antenna patterns, both approaches are suitable for 3GPP New Radio cellular networks. The performance gain, compared to the heavily used exhaustive and iterative search schemes, is more prominent in dense networks and large antenna regimes and can be further improved by optimizing the beam forming code-books.

  • 187.
    Silva, Nishal
    et al.
    Sheffield Hallam Univ, Dept Engn & Math, Sheffield, S Yorkshire, England..
    Weeraddana, Pradeep Chathuranga
    Univ Moratuwa, Dept Elect & Telecomm Engn, Moratuwa, Sri Lanka..
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    On Musical Onset Detection via the S-Transform2018In: 2018 CONFERENCE RECORD OF 52ND ASILOMAR CONFERENCE ON SIGNALS, SYSTEMS, AND COMPUTERS / [ed] Matthews, M B, IEEE , 2018, p. 1080-1085Conference paper (Refereed)
    Abstract [en]

    Musical onset detection is a key component in any beat tracking system. Existing onset detection methods are based on temporal/spectral analysis, or methods that integrate temporal and spectral information together with statistical estimation and machine learning models. In this paper, we propose a method to localize onset components in music by using the S-transform, and thus, the method is purely based on temporal/spectral data. Unlike the other methods based on temporal/spectral data, which usually rely on the short time Fourier transform (STET), our method enables effective isolation of crucial frequency subbands due to the frequency dependent resolution of S-transform. Moreover, numerical results show, even with less computationally intensive steps, the proposed method can closely resemble the performance of more resource intensive statistical estimation based approaches.

  • 188. Speranzon, A.
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl H.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Sangiovanni-Vincentelli, A.
    A distributed minimum variance estimator for sensor networks2008In: IEEE Journal on Selected Areas in Communications, ISSN 0733-8716, E-ISSN 1558-0008, Vol. 26, no 4, p. 609-621Article in journal (Refereed)
    Abstract [en]

    A distributed estimation algorithm for sensor networks is proposed. A noisy time-varying signal is jointly tracked by a network of sensor nodes, in which each node computes its estimate as a weighted sum of its own and its neighbors' measurements and estimates. The weights are adaptively updated to minimize the variance of the estimation error. Both estimation and the parameter optimization is distributed; no central coordination of the nodes is required. An upper bound of the error variance in each node is derived. This bound decreases with the number of neighboring nodes. The estimation properties of the algorithm are illustrated via computer simulations, which are intended to compare our estimator performance with distributed schemes that were proposed previously in the literature. The results of the paper allow to trading-off communication constraints, computing efforts and estimation quality for a class of distributed filtering problems.

  • 189. Speranzon, Alberto
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Björn
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Adaptive distributed estimation over wireless sensor networks with packet losses2007In: Proceedings of the IEEE Conference on Decision and Control, 2007, p. 5472-5477Conference paper (Refereed)
    Abstract [en]

    A distributed adaptive algorithm to estimate a time-varying signal, measured by a wireless sensor network, is designed and analyzed. The presence of measurement noises and of packet losses is considered. Each node of the network locally computes adaptive weights that guarantee to minimize the estimation error variance. Decentralized conditions on the weights, which ensure the stability of the estimates throughout the overall network, are also considered. A theoretical performance analysis of the scheme is carried out both in the presence of perfect and lossy links. Numerical simulations illustrate performance for various network topologies and packet loss probabilities. © 2007 IEEE.

  • 190.
    Speranzon, Alberto
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    A distributed estimation algorithm for tracking over wireless sensor networks2007In: 2007 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, 2007, p. 3088-3093Conference paper (Refereed)
    Abstract [en]

    A new distributed estimation algorithm for tracking using a wireless sensor network is presented. We investigate how to track a time varying signal, noisily sensed by the nodes of the network. The algorithm is distributed, meaning that it does not require a central coordination among the nodes. Moreover, the proposed approach is scalable with respect to the network size, which means that its complexity does not grow with respect to the total number of nodes. The algorithm designed turns out to be composed by a cascade structure. Local constraints are determined to guarantee the global asymptotic stability of the estimation error. The algorithm can be applied e.g., for the position estimation, temporal synchronization, as well as tracking of signals. Performance is illustrated by simulations, where our filter is shown to behave better than other distributed schemes proposed in the literature.

  • 191. Speranzon, Alberto
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Distributed and collaborative estimation over wireless sensor networks2006In: PROCEEDINGS OF THE 45TH IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-14: IEEE Conference on Decision and Control, IEEE , 2006, p. 1025-1030Conference paper (Refereed)
    Abstract [en]

    A new distributed algorithm for cooperative estimation of a slowly time-varying signal using a wireless sensor network is presented. The estimate in each node is based on a so called consensus algorithm, which weights measurements and estimates of neighboring nodes. The algorithm is therefore scalable with the number of network nodes. It requires only limited information exchange between nodes and computations in each node. The weights are locally optimized based on a minimum variance criterion. Numerical results show that the proposed algorithm exhibits good performance compared to other distributed algorithms proposed in the literature.

  • 192. Speranzon, Alberto
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    On distributed estimation for sensor networks2007Conference paper (Refereed)
    Abstract [en]

    Distributed estimators for sensor networks are discussed. The considered problem is on how to track a noisy timevarying signal jointly with a network of sensor nodes. We present a recent scheme in which each node computes its estimate as a weighted sum of its own and its neighbors ’ measurements and estimates. The weights are adaptively updated to minimize the variance of the estimation error. Theoretical and practical properties of the algorithm are illustrated. The results provide a tool to trade-off communication constraints, computing efforts and estimation quality.

  • 193. Tiberi, U.
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Di Benedetto, M. D.
    Self-triggered control of multiple loops over IEEE 802.15.4 networks2011In: IFAC Proceedings Volumes: (IFAC-PapersOnline), 2011, no PART 1, p. 13893-13898Conference paper (Refereed)
    Abstract [en]

    Given the communication savings offered by self-triggered sampling, it is becoming an essential paradigm for closed-loop control over energy-constrained wireless sensor networks (WSNs). The understanding of the performance of self-triggered control systems when the feedback loops are closed over IEEE 802.15.4 WSNs is of major interest, since the communication standard IEEE 802.15.4 is the de-facto the reference protocol for energy-efficient WSNs. In this paper, a new approach to control several processes over a shared IEEE 802.15.4 network by self-triggered sampling is proposed. It is shown that the sampling time of the processes, the protocol parameters, and the scheduling of the transmissions must be jointly selected to ensure stability of the processes and energy efficiency of the network. The challenging part of the proposed analysis is ensuring stability and making an energy efficient scheduling of the state transmissions. These transmissions over IEEE 802.15.4 are allowed only at certain time slots, which are difficult to schedule when multiple control loops share the network. The approach establishes that the joint design of self-triggered samplers and the network protocol 1) ensures the stability of each loop, 2) increases the network capacity, 3) reduces the number of transmissions of the nodes, and 4) increases the sleep time of the nodes. A new dynamic scheduling problem is proposed to control each process, adapt the protocol parameters, and reduce the energy consumption. An algorithm is then derived, which adapts to any choice of the self-triggered samplers of every control loop. Numerical examples illustrate the analysis and show the benefits of the new approach.

  • 194.
    Tiberi, Ubaldo
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Domenica Di Benedetto, M.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    System level design of self-triggered IEEE 802.15.4 networked control loops increases the network capacity2011Conference paper (Refereed)
  • 195.
    Tiberi, Ubaldo
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Di Benedetto, M. D.
    Adaptive self-triggered control over IEEE 802.15.4 networks2010Conference paper (Refereed)
    Abstract [en]

    The communication protocol IEEE 802.15.4 is becoming pervasive for low power and low data rate wireless sensor networks (WSNs) applications, including control and automation. Nevertheless, there is not yet any adequate study about control systems networked by this protocol. In this paper, the stability of IEEE 802.15.4 networked control systems (NCSs) is addressed. While in recent works fundamental results are developed for networks that are abstracted only in terms of packet loss and time delays, here the constraints imposed by the protocol to the feedback channel and the network energy consumption are explicitly considered. A general analysis for linear systems with parameter uncertainty and external bounded disturbances with control loops closed over IEEE 802.15.4 networks is proposed. To reduce the number of transmissions and thus save energy, a self-triggered control strategy is used. A sufficient stability condition is given as function of both the protocol and control parameters. A decentralized algorithm to adapt jointly the self-triggered control and the protocol parameters is proposed. It is concluded that stability is not always guaranteed unless protocol parameters are appropriately tuned, and that event-triggered control strategies may be difficult to use with the current version of IEEE 802.15.4.

  • 196.
    Tiberi, Ubaldo
    et al.
    Volvo Group Trucks Technology, Göteborg, Sweden .
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Johansson, Karl Henrik
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Domenica Di Benedetto, M.
    Energy-efficient sampling of networked control systems over IEEE 802.15.4 wireless networks2013In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 49, no 3, p. 712-724Article in journal (Refereed)
    Abstract [en]

    Self-triggered sampling is an attractive paradigm for closed-loop control over energy-constrained wireless sensor networks (WSNs) because it may give substantial communication savings. The understanding of the performance of self-triggered control systems when the feedback loops are closed over IEEE 802.15.4 WSNs is of major interest, since the communication standard IEEE 802.15.4 is the de-facto reference protocol for energy-efficient WSNs. In this paper, a new approach to control several processes over a shared IEEE 802.15.4 network by self-triggered sampling is proposed. It is shown that the sampling time of the processes, the protocol parameters, and the scheduling of the transmissions must be jointly selected to achieve a good performance of the closed-loop system and an energy-efficient utilization of the network. The challenging part of the proposed analysis is ensuring globally uniformly ultimately boundedness of the controlled processes while providing efficient scheduling of the process state transmissions. Such a scheduling is difficult when asynchronous multiple control loops share the network, because transmissions over IEEE 802.15.4 are allowed only at certain time slots. The proposed approach establishes that the joint design of self-triggered samplers and the network protocol (1) ensures globally uniformly ultimately boundedness of each control loop, (2) reduces the number of sensor transmissions, and (3) increases the sleep time of the transmitting nodes. A new dynamic scheduling problem is proposed for the joint control of each process and network protocol adaptation. An algorithm is derived, which adapts the network parameters according to the self-triggered sampler of every control loop. Numerical examples illustrate the analysis and show the benefits of the approach. It is concluded that self-triggered control strategies over WSNs ensure desired control performance, reduce the network utilization, and reduce energy consumption only if the protocol parameters are appropriately regulated.

  • 197. Turchet, L.
    et al.
    Benincaso, M.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Network and Systems engineering.
    Examples of use cases with Smart Instruments2017In: AM '17 Proceedings of the 12th International Audio Mostly Conference on Augmented and Participatory Sound and Music Experiences, Association for Computing Machinery (ACM), 2017, Vol. Part F131930, article id a47Conference paper (Refereed)
    Abstract [en]

    This paper presents some of the possibilities for interaction between performers, audiences, and their smart devices, offered by the novel family of musical instruments, the Smart Instruments. For this purpose, some implemented use cases are described, which involved a preliminary prototype of MIND Music Labs' Sensus Smart Guitar, the first exemplar of Smart Instrument. Sensus consists of a guitar augmented with sensors, actuators, onboard processing, and wireless communication. Some of the novel interactions enabled by Sensus technology are presented, which are based on connectivity of the instrument to smart devices, virtual reality headsets, and the cloud.

  • 198.
    Turchet, Luca
    et al.
    Queen Mary Univ London, Ctr Digital Mus, London E1 4NS, England..
    Fischione, Carlo
    KTH, School of Electrical Engineering and Computer Science (EECS), Network and Systems engineering.
    Essl, Georg
    Univ Wisconsin, Coll Letters & Sci, Milwaukee, WI 53211 USA..
    Keller, Damian
    Univ Fed Acre, Amazon Ctr Mus Res NAP, BR-69920900 Rio Branco, Brazil..
    Barthet, Mathieu
    Queen Mary Univ London, Ctr Digital Mus, London E1 4NS, England..
    Internet of Musical things: Visit and Challenges2018In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 61994-62017Article in journal (Refereed)
    Abstract [en]

    The Internet of Musical Things (IoMusT) is an emerging research field positioned at the intersection of Internet of Things, new interfaces for musical expression, ubiquitous music, human-computer interaction, artificial intelligence, and participatory art. From a computer science perspective, IoMusT refers to the networks of computing devices embedded in physical objects (musical things) dedicated to the production and/or reception of musical content. Musical things, such as smart musical instruments or wearables, are connected by an infrastructure that enables multidirectional communication, both locally and remotely. We present a vision in which the IoMusT enables the connection of digital and physical domains by means of appropriate information and communication technologies, fostering novel musical applications and services. The ecosystems associated with the IoMusT include interoperable devices and services that connect musicians and audiences to support musician-musician, audience-musicians, and audience-audience interactions. In this paper, we first propose a vision for the IoMusT and its motivations. We then discuss five scenarios illustrating how the IoMusT could support: 1) augmented and immersive concert experiences; 2) audience participation; 3) remote rehearsals; 4) music e-learning; and 5) smart studio production. We identify key capabilities missing from today's systems and discuss the research needed to develop these capabilities across a set of interdisciplinary challenges. These encompass network communication (e.g., ultra-low latency and security), music information research (e.g., artificial intelligence for real-time audio content description and multimodal sensing), music interaction (e.g., distributed performance and music e-learning), as well as legal and responsible innovation aspects to ensure that future IoMusT services are socially desirable and undertaken in the public interest.

  • 199. Valentini, Roberto
    et al.
    Levorato, Marco
    Donald Bren School of Information and Computer Science.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Performance analysis of IEEE 802.15.3c-Based mmW wireless networks2015In: 2015 49th Annual Conference on Information Sciences and Systems, CISS 2015, Institute of Electrical and Electronics Engineers (IEEE), 2015, article id 7086886Conference paper (Refereed)
    Abstract [en]

    The IEEE 802.15.3c standard defines physical layer and Medium Access Control (MAC) specifications for millimeter-Wave Wireless Personal Area Networks. The MAC protocol implements a combination of random channel access and time division multiple access mechanisms to exploit the sectorization granted by the directional antennas. In this work, a novel two-level stochastic model is presented to capture the complex dynamics of channel access in this network environment. Different from prior work, the finite temporal horizon of the channel contention phase is accurately modeled, and the common assumption of saturated terminals is removed. Based on the proposed modeling framework, the allocation of time resource to each sector is optimized to improve the network performance.

  • 200. Weeraddana, P. C.
    et al.
    Fischione, Carlo
    KTH, School of Electrical Engineering (EES), Network and Systems engineering.
    On the Privacy of Optimization2017In: IFAC-PapersOnLine, ISSN 2405-8963, Vol. 50, no 1, p. 9502-9508Article in journal (Refereed)
    Abstract [en]

    In distributed or multiparty computations, optimization theory methods offer appealing privacy properties compared to cryptography and differential privacy methods. However, unlike cryptography and differential privacy, optimization methods currently lack a formal quantification of the privacy they can provide. The main contribution of this paper is to propose a quantification of the privacy of a broad class of optimization approaches. The optimization procedures generate a problem's data ambiguity for an adversarial observer, which thus observes the problem's data within an uncertainty set. We formally define a one-to-many relation between a given adversarial observed message and an uncertainty set of the problem's data. Based on the uncertainty set, a privacy measure is then formalized. The properties of the proposed privacy measure are analyzed. The key ideas are illustrated with examples, including localization and average consensus.

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