D. Starobinski

Boston University, Boston, Massachusetts, United States

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Publications (101)59.29 Total impact

  • Cankut Orakcal, David Starobinski
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    ABSTRACT: We introduce a theoretical framework to formally analyze the vulnerability of IEEE 802.11 rate adaptation algorithms (RAAs) to selective jamming attacks, and to develop countermeasures providing provable performance guarantees. Thus, we propose a new metric called Rate of Jamming (RoJRoJ), wherein a low RoJRoJ implies that an RAA is highly vulnerable to jamming attacks, while a high RoJRoJ implies that the RAA is resilient. We prove that several state-of-the-art RAAs, such as ARF and SampleRate, have a low RoJRoJ (i.e., 10%10% or lower). Next, we propose a robust RAA, called Randomized ARF (RARF). Using tools from renewal theory, we derive a closed-form lower bound on the RoJRoJ of RARF. We validate our theoretical analysis using ns-3 simulations and show that the minimum jamming rate required against RARF is about 33%33% (i.e., at least three times higher than the RoJRoJ of other RAAs).
    Performance Evaluation 05/2014; · 0.84 Impact Factor
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    ABSTRACT: We experimentally investigate the benefits of multihop networking for intra-car data aggregation under the current state-of-the-art Collection Tree Protocol (CTP). We show how this protocol actively adjusts collection routes according to channel dynamics in various practical car environments, resulting in performance gains over single-hop aggregation. Throughout our experiments, we target traditional performance metrics such as delivery rate, number of transmissions per packet, and delay, and our results confirm, both qualitatively and quantitatively, that multi-hop communication can provide a reliable and robust approach for data collection within a car.
    Vehicular Technology Conference (VTC Spring), 2013 IEEE 77th; 06/2013
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    ABSTRACT: Few technical details are available about the various sensors embedded in modern smartphones, and what details are available can be hard to assemble and interpret by the broader technical community that uses these devices. Since the physical and electromagnetic aspects of the sensors' operation can significantly affect the analysis and use of their data, it is essential for those who rely on these data to understand these details. As such, the authors provide a simplified and yet technically precise explanation of some of the sensors found on the Motorola Droid, which are representative of sensors found in most smartphones. The authors specifically explain its proximity sensor, Hall effect magnetometer, capacitive accelerometer, orientation sensor, and light sensor. Each sensor is described using illustrations and experiments that are provided to demonstrate some unexpected behaviors.
    International Journal of Handheld Computing Research. 04/2013; 4(2):69-80.
  • Ashraf Al Daoud, Murat Alanyali, David Starobinski
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    ABSTRACT: Ongoing regulatory reforms have led to several novel spectrum sharing models under the general umbrella of dynamic spectrum sharing. The private commons model introduced by FCC in 2004 allows spectrum licensees to provide secondary access to spectrum on an opportunistic basis while retaining ownership. Since wireless communication systems are typically overprovisioned in order to deliver service-level guarantees to (primary) users under short-term load variations, this model bears significant potential by facilitating utilization of temporal and spatial surplus of capacity through serving secondary users at possibly different service levels. A potential barrier to adoption of the private commons model is the uncertainty about secondary price–demand relationship which is difficult to predict in an emerging market: A selected price for secondary access may be profitable for some values of secondary demand but not for others, leading to a profound uncertainty about ultimate benefit of spectrum sharing. This paper aims to eliminate such an uncertainty by devising concrete guidelines and methods for profitability. The paper establishes that the price of secondary spectrum access can be chosen to guarantee profitability for any value of secondary demand: It is shown that for both the coordinated and uncoordinated commons regimes a profitable price should exceed a threshold value, which can be calculated. Hence profitability of private commons is insensitive to the demand function. This observation has two complementary interpretations: From a business perspective it provides a constructive approach to profitability; and from a regulatory perspective it provides reassurance that private commons is a healthy model. The paper also leverages the insensitivity property and outlines a technique to further enhance revenue via iterative spectrum offerings.
    Telecommunications Policy 01/2013; 37(s 2–3):231–240. · 1.59 Impact Factor
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    ABSTRACT: Several collection protocols have been developed to achieve efficient gathering of data in Wireless Sensor Networks (WSN) including intra-car WSN. Though there exist WSN tools capable of controlling, monitoring, and displaying sensor data, there is still a need for a general benchmarking tool capable of visualizing, evaluating, and comparing the network layer performance of these protocols. In an effort to fill this gap, we present TeaCP, a prototype Toolkit for the evaluation and analysis of Collection Protocols in both simulation and experimental environments. Through simulation of an intra-car WSN and real lab experiments, we demonstrate the functionality of TeaCP for comparing the performance of two prominent collection protocols, the Collection Tree Protocol (CTP) and the Backpressure Collection Protocol (BCP).
    COMCAS; 01/2013
  • Aylin Turhan, Murat Alanyali, David Starobinski
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    ABSTRACT: We study optimal admission control in a two-class preemptive loss system. A class-1 customer arrival aborts service of a class-2 customer if the system is full upon arrival. Each successfully serviced class-2 customer leads to a reward, whereas each aborted class-2 customer incurs a cost. Using dynamic programming, we characterize optimal admission control for class-2 customers that maximizes the long-run average profit. The optimal admission control policy depends only on the total occupancy and is of threshold type.
    Operations Research Letters 11/2012; 40(6):510–515. · 0.52 Impact Factor
  • E. Kavurmacioglu, M. Alanyali, D. Starobinski
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    ABSTRACT: Recent initiatives allow cellular providers to offer spot service of their licensed spectrum, paving the way to dynamic secondary spectrum markets. This paper characterizes market outcomes when multiple providers are drawn into competition for secondary demand. We study a game-theoretic model in which each provider aims to enhance its revenue by opportunistically serving secondary demand, while also serving dedicated primary demand. The secondary demand is a function of the price being charged. We consider two philosophies for sharing spectrum between primary and secondary demand: In coordinated access, spectrum providers have the option to decline a secondary access request if that helps enhance their revenue. We explicitly characterize a break-even price such that profitability of secondary access provision is guaranteed if secondary access is priced above the break-even price, regardless of the volume of secondary demand. Consequently, we establish that competition among providers that employ coordinated access leads to a price war. In particular market sharing above the break-even price is not an equilibrium outcome. This conclusion is valid for arbitrary secondary-demand functions. While the demand function does not play a part in determining the winner, it does affect the price of secondary access as exercised by the winning provider. In uncoordinated access, primary and secondary users share spectrum on equal basis, akin to the sharing modality of ISM bands. We demonstrate that market equilibrium in an uncoordinated access setting can be fundamentally different as it opens up the possibility of providers sharing the market at higher prices.
    Dynamic Spectrum Access Networks (DYSPAN), 2012 IEEE International Symposium on; 01/2012
  • A. Turhan, M. Alanyali, D. Starobinski
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    ABSTRACT: We consider a service provider that accommodates two classes of users: primary users (PUs) and secondary users (SUs). SU demand is elastic to price whereas PU demand is inelastic. When a PU arrives to the system and finds all channels busy, it preempts an SU unless there are no SUs in the system. Call durations are exponentially distributed and their means are identical. We study the optimal pricing policy of SUs by using dynamic programming to maximize the total expected discounted profit over finite and infinite horizons, and the average profit. Our main contribution is to show that although the system is modeled as a two-dimensional Markov chain, the optimal pricing policy depends only on the total number of users in the system (PUs and SUs), i.e. the total occupancy. We also demonstrate that optimal prices are increasing with the total occupancy. Finally, we describe applications of these results to the special case of admission control and show that the optimal pricing policy structure of the original system is not preserved for systems with elastic PUs.
    Decision and Control (CDC), 2012 IEEE 51st Annual Conference on; 01/2012
  • Aylin Turhan, M. Alanyali, D. Starobinski
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    ABSTRACT: We study optimal admission control of secondary users (SUs) in cognitive radio (CR) networks in presence of preemption. In this model, when a primary user (PU) arrives to the system and finds all the channels busy, it preempts an SU unless all the users in the system are PUs. We apply admission control on the SUs only. Using dynamic programming (DP), we find the optimal admission control policy that maximizes the long-run average profit. As our main contribution, we show that the optimal admission control of the SUs depends only on the total number of users in the system (i.e. it does not depend on the number of PUs and SUs in the system individually) and is of threshold type. Therefore, although the system is modeled as a two-dimensional Markov chain, our findings allow simple and efficient computation of the optimal control policy.
    Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), 2012 10th International Symposium on; 01/2012
  • C. Orakcal, D. Starobinski
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    ABSTRACT: Recent experimental studies reveal that several well-known and widely deployed rate adaptation algorithms (RAAs) in 802.11 WLANs are vulnerable to selective jamming attacks. However, previous work resorts to complex jamming strategies that are hard to implement and does not provide applicable solutions to this problem. In this work, we analyze the vulnerabilities of existing RAAs to simple jamming attacks and propose judicious use of randomization to address this problem. We introduce a theoretical framework based on a bursty periodic jamming model to analyze the vulnerabilities of popular RAAs, such as ARF and SampleRate. Our parameterized analysis shows that a jamming rate of 10% or below is sufficient to bring the throughput of these algorithms below the base rate of 1 Mb/s. Thereafter, we propose Randomized ARF (RARF), which has higher resistance to jamming attacks. We derive a closed-form lower bound on the minimum jamming rate required to keep the RARF throughput below the base rate. Finally, we conduct ns-3 simulations implementing various RAAs and jamming strategies for an IEEE 802.11g WLAN. Our simulations validate jamming strategies under different channel models and show that the minimum jamming rate required against RARF is about 33%.
    Global Communications Conference (GLOBECOM), 2012 IEEE; 01/2012
  • Jiaxi Jin, Wei Si, D. Starobinski, A. Trachtenberg
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    ABSTRACT: We consider the problem of synchronizing prioritized data on two distinct hosts in disruption-tolerant networks (DTNs). To this effect, we propose and analyze a new interactive protocol for priority-oriented synchronization, called P-CPI, that is especially efficient in terms of bandwidth usage. This middleware protocol has features that are particularly useful for DTN routing in constrained or tactical environments, including (i) communication and computational complexity primarily tied to the number of differences between the hosts rather than the amount of the data overall and (ii) a memoryless fast restart after interruption. We provide a novel analysis of this protocol, substantiating a high-probability performance bound and memoryless fast-restart in logarithmic time. As a proof of concept, we demonstrate improved delivery rate and reduced metadata and average delay in a DARPA-supported DTN routing application called RAPID.
  • Source
    Ashish Agarwal, David Starobinski, Thomas D. C. Little
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    ABSTRACT: Delay-tolerant network (DTN) architectures have recently been proposed as a means to enable efficient routing of messages in vehicular area networks (VANETs), which are characterized by alternating periods of connectivity and disconnection. Under such architectures, when multihop connectivity is available, messages propagate at the speed of radio over connected vehicles. On the other hand, when vehicles are disconnected, messages are carried by vehicles and propagate at vehicle speed. Our goal in this paper is to analytically determine what gains are achieved by DTN architectures and under which conditions, using the average message propagation speed as the primary metric of interest. We develop an analytical model for a bidirectional linear network of vehicles, as found on highways. We derive both upper and lower bounds on the average message propagation speed by exploiting a connection with the classical pattern-matching problem in probability theory. The bounds reveal an interesting phase transition behavior. Specifically, we find out that, below a certain critical threshold, which is a function of the traffic density in each direction, the average message speed is the same as the average vehicle speed, i.e., DTN architectures provide no gain. On the other hand, we determine another threshold above which the average message speed quickly increases as a function of traffic density and approaches radio speed. Based on the bounds, we also develop an approximation model for the average message propagation speed that we validate through numerical simulations.
    IEEE Transactions on Intelligent Transportation Systems 01/2012; 13:249-263. · 3.06 Impact Factor
  • Source
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    ABSTRACT: We consider the problem of generating a connected identifying code for an arbitrary graph. After a brief motivation, we show that the decision problem regarding the existence of such a code is NP-complete, and we propose a novel polynomial-time approximation ${\tt ConnectID}$ that transforms any identifying code into a connected version of at most twice the size, thus leading to an asymptotically optimal approximation bound. When the input identifying code to ${\tt ConnectID}$ is robust to graph distortions, we show that the size of the resulting connected code is related to the best error-correcting code of a given minimum distance, permitting the use of known coding bounds. In addition, we show that the size of the input and output codes converge for increasing robustness, meaning that highly robust identifying codes are almost connected. Finally, we evaluate the performance of ${\tt ConnectID}$ on various random graphs. Simulations for Erdős–Rényi random graphs show that the connected codes generated are actually at most 25% larger than their unconnected counterparts, while simulations with robust input identifying codes confirm that robustness often provides connectivity for free.
    IEEE Transactions on Information Theory 01/2012; 58(7):4814-4824. · 2.62 Impact Factor
  • Kan Lin, D. Starobinski, A. Trachtenberg, S. Agarwal
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    ABSTRACT: Many applications in wireless cellular networks rely on the ability of the network to reliably and efficiently disseminate data to a large client audience. The stochastic nature of packet loss across receivers and channel interference constraints between cells complicate this task, however. In this paper, we analyze the problem of minimizing the delay of data dissemination in dense multi-channel wireless cellular networks, using rateless coding transmission. We begin with an extreme value analysis of the delay in a single cell setting, and show that the growth rate of this random variable becomes deterministic as the client audience scales up. Next, we extend the analysis to multi-cell, multi-channel settings and derive tight performance bounds on the delay. Our analysis reveals that the availability of more channels does not always reduce delay proportionally. This sub-linear gain effect is guaranteed to occur if the difference between the chromatic number and the fractional chromatic number of the graph is greater than one.
    Information Sciences and Systems (CISS), 2012 46th Annual Conference on; 01/2012
  • H. Mutlu, M. Alanyali, D. Starobinski, A. Turhan
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    ABSTRACT: We consider a wireless provider who caters to two classes of customers, namely primary users (PUs) and secondary users (SUs). PUs have long term contracts while SUs are admitted and priced according to current availability of excess spectrum. The average rate at which SUs attempt to access the spectrum is a function on the currently advertised price, referred to as the demand function. We analyze the problem of maximizing the average profit gained by admissions of SUs, when the demand function is unknown. We introduce a new on-line algorithm, called Measurement-based Threshold Pricing (MTP), that requires the optimization of only two parameters, a price and a threshold, whereby SU calls are admitted and charged a fixed price when the channel occupancy is lower than the threshold and rejected otherwise. At each iteration, MTP measures the average arrival rate of SUs corresponding to a certain test price. We prove that these measurements of the secondary demand are sufficient for MTP to converge to a local optimal price and corresponding optimal threshold, within a number of measurements that is logarithmic in the total number of possible prices. We further provide an adaptive version of MTP that adjusts to time-varying demand and establish its convergence properties. We conduct numerical studies showing the convergence of MTP to near-optimal online profit and its superior performance over a traditional reinforcement learning approach.
    IEEE Journal on Selected Areas in Communications 01/2012; 30(11):2285-2294. · 3.12 Impact Factor
  • A. Al Daoud, M. Alanyali, D. Starobinski
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    ABSTRACT: We investigate profitability from secondary spectrum provision under unknown relationships between price charged for spectrum use and demand drawn at the given price. We show that profitability is governed by the applied admission policy and the price charged to secondary users. We explicitly identify a critical price (market entry price) such that if secondary demand is charged below that price, the licensee endures losses from spectrum provision, regardless of the applied admission policy. Furthermore, we show that an admission policy that admits secondary demand only when no channel is occupied is profitable for any price that exceeds the critical price. We prove that this policy is profit-robust to variations in secondary demand, i.e., if the policy is profitable for a certain price, it will be profitable for any secondary demand that the price generates, as long as the price generates demand. We also investigate profitability from a set of policies that allow more secondary users to access spectrum by defining the number of users that can be concurrently served. Our results demonstrate profit-robustness of these policies and explicitly characterize profitable prices. We provide a numerical study to verify our theoretical findings.
    Global Communications Conference (GLOBECOM), 2012 IEEE; 01/2012
  • C. Orakcal, D. Starobinski
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    ABSTRACT: Wireless communication protocols for unlicensed frequency bands support rate adaptation algorithms (RAAs) to cope with time-varying channel conditions. RAAs are not designed to operate against adversarial behavior, however. In this work, we analyze the vulnerabilities of two state-of-the-art RAAs, Minstrel and RARF, against a smart jamming model, whereby an adversary learns the current rate of transmission of each packet before deciding whether to jam the packet or not. Our parameterized analysis, validated by ns-3 simulations, shows that a jamming rate of only 10% is sufficient to bring the throughput of Minstrel below the base rate of 1 Mb/s, whereas RARF requires a jamming rate of 16:7%. These findings are notable since previous work showed that the randomized nature of RARF and Minstrel make them resilient to simpler jamming attacks. The paper concludes by sketching possible solutions to mitigate these sophisticated attacks.
    Cognitive Radio Oriented Wireless Networks and Communications (CROWNCOM), 2012 7th International ICST Conference on; 01/2012
  • Source
    R. Cohen, N. Fazlollahi, D. Starobinski
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    ABSTRACT: In response to the high throughput needs of grid and cloud computing applications, several production networks have recently started to support advance reservation of dedicated circuits. An important open problem within this context is to devise advance reservation algorithms that can provide provable throughput performance guarantees independently of the specific network topology and arrival pattern of reservation requests. In this paper, we first show that the throughput performance of greedy approaches, which return the earliest possible completion time for each incoming request, can be arbitrarily worse than optimal. Next, we introduce two new online, polynomial-time algorithms for advance reservation, called BatchAll and BatchLim. Both algorithms are shown to be throughput-optimal through the derivation of delay bounds for 1 + ε bandwidth augmented networks. The BatchLim algorithm has the advantage of returning the completion time of a connection immediately as a request is placed, but at the expense of looser delay performance than BatchAll. We then propose a simple approach that limits path dispersion, i.e., the number of parallel paths used by the algorithms, while provably bounding the maximum reduction factor in the transmission throughput. We prove that the number of paths needed to approximate any flow is quite small and never exceeds the total number of edges in the network. Through simulation for various topologies and traffic parameters, we show that the proposed algorithms achieve reasonable delay performance, even at request arrival rates close to capacity bounds, and that three to five parallel paths are sufficient to achieve near-optimal performance.
    IEEE/ACM Transactions on Networking 11/2011; · 2.01 Impact Factor
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    A. Aziz, D. Starobinski, P. Thiran
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    ABSTRACT: We investigate, both theoretically and experimentally, the stability of CSMA-based wireless mesh networks, where a network is said to be stable if and only if the queue of each relay node remains (almost surely) finite. We identify two key factors that impact stability: the network size and the so-called “stealing effect,” a consequence of the hidden-node problem and nonzero transmission delays. We consider the case of a greedy source and prove, by using Foster's theorem, that three-hop networks are stable, but only if the stealing effect is accounted for. We also prove that four-hop networks are, on the contrary, always unstable (even with the stealing effect) and show by simulations that instability extends to more complex linear and nonlinear topologies. To tackle this instability problem, we propose and evaluate a novel, distributed flow-control mechanism called EZ-flow. EZ-flow is fully compatible with the IEEE 802.11 standard (i.e., it does not modify headers in packets), can be implemented using off-the-shelf hardware, and does not entail any communication overhead. EZ-flow operates by adapting the minimum congestion window parameter at each relay node, based on an estimation of the buffer occupancy at its successor node in the mesh. We show how such an estimation can be conducted passively by taking advantage of the broadcast nature of the wireless channel. Real experiments, run on a nine-node test-bed deployed over four different buildings, show that EZ-flow effectively smooths traffic and improves delay, throughput, and fairness performance.
    IEEE/ACM Transactions on Networking 09/2011; · 2.01 Impact Factor
  • Source
    M. Alanyali, A. Al Daoud, D. Starobinski
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    ABSTRACT: We characterize policies and prices for secondary spectrum provision whose profitability is insensitive to the demand curve. In more explicit terms, the paper provides a critical price value such that if secondary access is priced above that value then allowing secondary access is profitable for the licensee as long as the price generates secondary demand. Conversely, if the price does not generate demand then the licensee does not incur any operational cost due to secondary service. Hence such characterization serves as a guarantee that a spectrum licensee can strictly avoid revenue loss due to participation in spectrum trading.
    New Frontiers in Dynamic Spectrum Access Networks (DySPAN), 2011 IEEE Symposium on; 06/2011

Publication Stats

1k Citations
59.29 Total Impact Points


  • 2001–2014
    • Boston University
      • Department of Electrical and Computer Engineering
      Boston, Massachusetts, United States
    • University of California, Berkeley
      • Department of Electrical Engineering and Computer Sciences
      Berkeley, California, United States
  • 2009–2011
    • Bar Ilan University
      • Department of Mathematics
      Ramat Gan, Tel Aviv, Israel
    • Nokia Research Center
      Palo Alto, California, United States
  • 2007
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 2006
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
  • 1996–2000
    • Technion - Israel Institute of Technology
      • Electrical Engineering Group
      Haifa, Haifa District, Israel