Results 1  10
of
36
Stochastic Sampling Algorithms for State Estimation of Jump Markov Linear Systems
 IEEE Transactions on Automatic Control
, 2000
"... Jump Markov linear systems are linear systems whose parameters evolve with time according to a finitestate Markov chain. Given a set of observations, our aim is to estimate the states of the finitestate Markov chain and the continuous (in space) states of the linear system. The computational cost ..."
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Cited by 22 (2 self)
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Jump Markov linear systems are linear systems whose parameters evolve with time according to a finitestate Markov chain. Given a set of observations, our aim is to estimate the states of the finitestate Markov chain and the continuous (in space) states of the linear system. The computational cost in computing conditional mean or maximum a posteriori (MAP) state estimates of the Markov chain or the state of the jump Markov linear system grows exponentially in the number of observations.
JAMRESISTANT COMMUNICATION WITHOUT SHARED SECRETS THROUGH THE USE OF CONCURRENT CODES
, 2007
"... We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop an ..."
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Cited by 16 (9 self)
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We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.
Keyless jam resistance
 in Proc. 8th Annual IEEE SMC Information Assurance Workshop (IAW
, 2007
"... Traditionally, omnidirectional, radio frequency (RF) communication has been made resistant to jamming by the use of a secret key that is shared by the sender and receiver. There are no known methods for achieving jam resistance without that shared key. Unfortunately, wireless communication is now re ..."
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Cited by 15 (5 self)
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Traditionally, omnidirectional, radio frequency (RF) communication has been made resistant to jamming by the use of a secret key that is shared by the sender and receiver. There are no known methods for achieving jam resistance without that shared key. Unfortunately, wireless communication is now reaching a scale and a level of importance where such secretkey systems are becoming impractical. For example, the civilian side of the Global Positioning System (GPS) cannot use a shared secret, since that secret would have to be given to all 6.5 billion potential users, and so would no longer be secret. So civilian GPS cannot currently be protected from jamming. But the FAA has stated that the civilian airline industry will transition to using GPS for all navigational aids, even during landings. A terrorist with a simple jamming system could wreak havoc at a major airport. No existing system can solve this problem, and the problem itself has not even been widely discussed. The problem of keyless jam resistance is important. There is a great need for a system that can broadcast messages without any prior secret shared between the sender and receiver. We propose the first system for keyless jam resistance: the BBC algorithm. We describe the encoding, decoding, and broadcast algorithms. We then analyze it for expected resistance to jamming and error rates. We show that BBC can achieve the same level of jam resistance as traditional spread spectrum systems, at just under half the bit rate, and with no shared secret. Furthermore, a hybrid system can achieve the same average bit rate as traditional systems. I.
NarrowBand Interference Suppression in TimeHopping ImpulseRadio Systems
 In Proceedings of the Conference on Ultra Wideband Systems and Technologies
, 2002
"... UltraWide band (UWB) radio systems have drawn a lot of attention during the last few years. These systems use very low transmission power, spreaded over a bandwidth of several gigahertz. The very low transmission power and the large bandwidth used, enable UWB radio systems to coexist with other na ..."
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Cited by 13 (0 self)
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UltraWide band (UWB) radio systems have drawn a lot of attention during the last few years. These systems use very low transmission power, spreaded over a bandwidth of several gigahertz. The very low transmission power and the large bandwidth used, enable UWB radio systems to coexist with other narrow band systems over the same frequency band without interfering the narrow band systems. Nevertheless, these narrow band systems may cause interference which may jam the UWB receiver completely. Since standard narrow band interference suppression techniques are not applicable, techniques for interference suppression have to be developed. This paper presents novel narrow band interference suppression algorithms for UWB radio systems. Theoretical analysis of these algorithms reveal that they can eliminate the narrow band interference almost completely. 1.
Jam resistant communications without shared secrets
 in Proceedings of the 3 rd International Conference on Information Warfare and Security
, 2008
"... Distribution A, Approved for public release, distribution unlimited Abstract. We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this prob ..."
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Cited by 10 (1 self)
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Distribution A, Approved for public release, distribution unlimited Abstract. We consider the problem of establishing jamresistant, wireless, omnidirectional communication channels when there is no initial shared secret. No existing system achieves this. We propose a general algorithm for this problem, the BBC algorithm, and give several instantiations of it. We develop and analyze this algorithm within the framework of a new type of code, concurrent codes, which are those superimposed codes that allow efficient decoding. Finally, we propose the Universal Concurrent Code algorithm, and prove that it covers all possible concurrent codes, and give connections between its theory and that of monotone Boolean functions.
Ultrawideband small scale channel modeling and its application to receiver design
, 2003
"... and its Application to Receiver Design ..."
Adaptive TimeVarying Cancellation of Wideband Interferences in SpreadSpectrum Communications Based on TimeFrequency Distributions
 IEEE Trans. Signal Processing
, 1999
"... The aim of this paper is to propose an adaptive method for suppressing wideband interferences in spread spectrum (SS) communications. The proposed method is based on the timefrequency representation of the received signal from which the parameters of an adaptive timevarying interference excision ..."
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Cited by 6 (0 self)
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The aim of this paper is to propose an adaptive method for suppressing wideband interferences in spread spectrum (SS) communications. The proposed method is based on the timefrequency representation of the received signal from which the parameters of an adaptive timevarying interference excision filter are estimated. The approach is based on the generalized WignerHough transform as an effective way to estimate the instantaneous frequency of parametric signals embedded in noise. The performance of the proposed approach is evaluated in the presence of linear and sinusoidal FM interferences plus white Gaussian noise in terms of SNR improvement factor and bit error rate (BER).
Performance Evaluation of 2D Adaptive Prediction Filters for Detection of Small Objects in Image Data
 IEEE Trans. Image Processing
, 1993
"... This paper studies the performance of two dimensional least mean square(TDLMS) adaptive filters as prewhitening filters for the detection of small objects in image data. The object of interest is assumed to have a very small spatial spread and is obscured by correlated clutter of much larger spatial ..."
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Cited by 6 (1 self)
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This paper studies the performance of two dimensional least mean square(TDLMS) adaptive filters as prewhitening filters for the detection of small objects in image data. The object of interest is assumed to have a very small spatial spread and is obscured by correlated clutter of much larger spatial extent. The correlated clutter is predicted and subtracted from the input signal, leaving components of the spatially small signal in the residual output. The receiver operating characteristics of a detection system augmented by a TDLMS prewhitening filter are plotted using MonteCarlo techniques. It is shown that such a detector has better operating characteristics than a conventional matched filter in the presence of correlated clutter. For very low signal to background ratios, TDLMS based detection systems show a considerable reduction in the number of false alarms. The output energy in both the residual and prediction channels of such filters is shown to be dependent on the correlation ...
Robust GMSK Demodulation Using Demodulator Diversity and Demodulator Diversity and BER Estimation
, 1997
"... This research investigates robust demodulation of Gaussian Minimum Shift Keying (GMSK) signals, using demodulator diversity and realtime biterrorrate (BER) estimation. GMSK is particularly important because of its use in prominent wireless standards around the world (GSM, DECT, CDPD, DCS1800, ..."
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Cited by 5 (0 self)
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This research investigates robust demodulation of Gaussian Minimum Shift Keying (GMSK) signals, using demodulator diversity and realtime biterrorrate (BER) estimation. GMSK is particularly important because of its use in prominent wireless standards around the world (GSM, DECT, CDPD, DCS1800, and PCS1900). The dissertation begins with a literature review of GMSK demodulation techniques (coherent and noncoherent) and includes an overview of singlechannel interference rejection techniques in digital wireless communications. Various forms of GMSK demodulation are simulated, including the limiter discriminator and di#erential demodulator (i.e., twentyfive variations in all). Ten represent new structures and variations. The demodulator performances are evaluated in realistic wireless environments, such as additive white Gaussian noise, cochannel interference, and multipath environments modeled by COST207 and SMRCIM. Certain
Suppression of Multiple Narrowband Interferers in a Spreadspectrum Communication System
 IEEE J. Select. Areas Commun
, 2000
"... We consider the problem of estimating and suppressing many unknown independent and timevarying interferers in a spreadspectrum communication system. The interferers are assumed to be present in a wide frequency range. In order to detect, estimate and track the interference, we use a bank of hidden ..."
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Cited by 3 (0 self)
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We consider the problem of estimating and suppressing many unknown independent and timevarying interferers in a spreadspectrum communication system. The interferers are assumed to be present in a wide frequency range. In order to detect, estimate and track the interference, we use a bank of hidden Markov model lters operating in the frequency domain. The hidden Markov model lters' outputs are then used to suppress the existing interference. The computational complexity of our scheme is only linear in the number of interferers. The simulation studies show that our proposed novel schemes adapt quickly in tracking the timevarying nature of the interference. 1 Introduction In this paper, we consider the problem of detecting, tracking and suppressing interference in a spreadspectrum communication system. The interference is assumed to consist of many unknown, independent and timevarying narrowband interferers. There are several advantages with spreading the spectrum of the signal th...