2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
ABSTRACT This work address the channel capacity problem which is the key issue in the new generat... more ABSTRACT This work address the channel capacity problem which is the key issue in the new generation mobile broadband network. The simulation framework for analysis of channel capacity solution based on usage of the heterogeneous networks in complex urban and indoor environment is introduced in this work. The impact of heterogeneous network on channel capacity is analyzed based on proposed simulation framework. The multi-parametric statistical channel model is used for simulation of the propagation conditions. The advantages and drawbacks for various deployment strategies of femtocells in presence of macro coverage are investigated. It is shown that shared frequency assignment with open access gives better overall channel capacity for majority of the mobile outdoor and indoor users.
IEEE Transactions on Aerospace and Electronic Systems, 2021
Fast Fourier transform (FFT) is one of the fundamental signal processing algorithms widely used i... more Fast Fourier transform (FFT) is one of the fundamental signal processing algorithms widely used in radar applications. The Radon–Fourier transform (RFT) can be seen as an FFT generalization that can overcome some of its limitations. This work derives three spectral RFT (SRFT) based approaches to address major challenges of the multiple-input multiple-output automotive radars. First, two SRFT-based approaches are derived to increase maximal target detection range by mitigation of target migration in range and direction of arrival, jointly, and by multidwell integration processing, which increases the radar coherent integration time without compromising its detection update rate. Next, SRFT-based approach is proposed to address the cluster-to-track association problem that arises in multiple distributed target tracking scenarios that characterize automotive radar operation in dense urban environments.
2021 29th European Signal Processing Conference (EUSIPCO), 2021
Implementation of the intra-coding code-division multiple access (CDMA) multiple-input multiple-o... more Implementation of the intra-coding code-division multiple access (CDMA) multiple-input multiple-output (MIMO) radars requires orthogonality between the transmitted codewords. The lack of complete orthogonality between practical codewords induces sidelobes in the received signal which mask weak targets and increase probability of false alarm (PFA). This work proposes a novel and efficient CLEAN CDMA-MIMO approach, which considers all the transmitted codewords and the receiver noise coloring. The performance of the proposed approach is evaluated via simulations of a practical automotive scenario.
The high-resolution automotive radar is a key component in autonomous driving sensing suite. Vibr... more The high-resolution automotive radar is a key component in autonomous driving sensing suite. Vibration of the host vehicle degrades the automotive radar performance in terms of the maximal detection range and probability of false alarm. This work analyzes the effect of the vehicle vibration on the automotive radar and proposes a method for its mitigation. The performance of the proposed approach is evaluated using collected radar measurements and measured vibration. It is shown that the proposed approach succeeds in vibration effect mitigation even with vibration model mismatch.
IEEE Transactions on Aerospace and Electronic Systems, 2021
This work addresses code division multiple access (CDMA) implementation of automotive multiple-in... more This work addresses code division multiple access (CDMA) implementation of automotive multiple-input multiple-output (MIMO) radars. The tansec frequency modulation (TSFM) is proposed as a single intracoding scheme for CDMA-MIMO radars. The properties of the TSFM coding family are analyzed and two novel codeword selection algorithms are proposed. The TSFM is compared to a variety of coding families by evaluating their autocorrelation and cross-correlation properties. The considered coding families are based on phase coding: Hadamard, Gold, optimal peak to sidelobe; and frequency coding: piecewise linear frequency modulated. Properties of the coding families are analyzed with a variety of novel criteria, which are especially useful for CDMA-MIMO radars. The performance of the CDMA-MIMO radar with different coding families is evaluated via simulations of practical multitarget automotive scenarios. It is shown that the frequency-based TSFM coding family outperforms the other considered coding families in terms of their cross-correlation properties.
2010 IEEE Sensor Array and Multichannel Signal Processing Workshop, 2010
The FCC E-911 Phase-2 requirements have motivated increased interest in the challenge of localizi... more The FCC E-911 Phase-2 requirements have motivated increased interest in the challenge of localizing mobile sources in a dense urban environment. E-911 Phase-2 requires wireless carriers to provide the location of a 911 caller with accuracy of 100 meters in 67% of cases and 300 meters in 95% of cases. This paper proposes information theoretic bounds on source localization performance in a dense urban environment based on the distribution of received energy as a function of time and angle of arrival from the multipath propagation. The surveillance area is discretized into a grid of partitions where the partition size can be interpreted as a source localization accuracy. The proposed lower bound provides a limit on the achievable source localization accuracy for a given SNR. The bound is evaluated for several urban propagation scenarios.
This work addresses the probability of detection problem and false alarm performance degradation ... more This work addresses the probability of detection problem and false alarm performance degradation in automotive radar scenarios with multipath induced ghost targets. A novel multipath mitigation method which evaluates correlation between the target and its hypothesized ghost tracks, is proposed. The performance of the proposed method is evaluated with simulations and by using collected radar measurements, in practical scenes of moving target vehicles in adjacency to flat reflective surface.
The Journal of the Acoustical Society of America, 2012
The big brown bat (Eptesicus fuscus) uses frequency modulated (FM) echolocation calls to accurate... more The big brown bat (Eptesicus fuscus) uses frequency modulated (FM) echolocation calls to accurately estimate range and resolve closely spaced objects in clutter and noise. They resolve glints spaced down to 2 μs in time delay which surpasses what traditional signal processing techniques can achieve using the same echolocation call. The Matched Filter (MF) attains 10-12 μs resolution while the Inverse Filter (IF) achieves higher resolution at the cost of significantly degraded detection performance. Recent work by Fontaine and Peremans [J. Acoustic. Soc. Am. 125, 3052-3059 (2009)] demonstrated that a sparse representation of bat echolocation calls coupled with a decimating sensing method facilitates distinguishing closely spaced objects over realistic SNRs. Their work raises the intriguing question of whether sensing approaches structured more like a mammalian auditory system contains the necessary information for the hyper-resolution observed in behavioral tests. This research estimates sparse echo signatures using a gammatone filterbank decimation sensing method which loosely models the processing of the bat's auditory system. The decimated filterbank outputs are processed with [script-l](1) minimization. Simulations demonstrate that this model maintains higher resolution than the MF and significantly better detection performance than the IF for SNRs of 5-45 dB while undersampling the return signal by a factor of six.
IEEE Transactions on Aerospace and Electronic Systems, 2010
ABSTRACT The problem of sequential Bayesian estimation in linear non-Gaussian problems is address... more ABSTRACT The problem of sequential Bayesian estimation in linear non-Gaussian problems is addressed. In the Gaussian sum filter (GSF), the non-Gaussian system noise, the measurement noise, and the posterior state densities are modeled by the Gaussian mixture model (GMM). The GSF is optimal under the minimum-mean-square error (MMSE) criterion, however it is impractical due to the exponential model order growth of the system probability density function (pdf). The proposed recursive estimator, named the Gaussian mixture Kalman filter (GMKF), combines the GSF and the model order reduction procedure. The posterior state density at each iteration is approximated by a lower order density. This model order reduction procedure minimizes the estimated Kullback-Leibler divergence (KLD) of the reduced order density from the original density at each step. The estimation performance of the proposed GMKF is compared with the interactive multiple modeling (IMM), particle filter (PF), Gaussian sum PF (GSPF), and the GSF with mixture reduction (MR) method via simulations. It is shown in several examples that the proposed GMKF outperforms the other tested algorithms in terms of estimation accuracy. The superior estimation performance of the GMKF is obtained at the expense of its computational complexity, which is higher than the IMM and the MR algorithms.
Page 1. .:. TECHNICAL PAPER REVIEW COMMITTEE The Technical Program Committee Chairs wish to thank... more Page 1. .:. TECHNICAL PAPER REVIEW COMMITTEE The Technical Program Committee Chairs wish to thank all of the Review Committee Members for their support Raviraj Adve Maria Greco Eric Mokole Fauzia Ahmad Marshall Greenspan Alberto Moreira Geoffrey Akers Hugh Griffiths Anders Nelander Chris Allen Joseph Guerci Xavier Neyt Richard Bamler Svein-Erik Hamran Trung Nguyen Jamie Bergin Ryan Hersey Yoann Paichard Igal Bilik Thomas Higgins James Palmer William Blair Braham Himed Jason Parker ...
ABSTRACT The Federal Communications Commission (FCC) Phase II enhanced 911 (E-911) requirements h... more ABSTRACT The Federal Communications Commission (FCC) Phase II enhanced 911 (E-911) requirements have motivated increased interest in the challenge of localizing mobile sources in urban environments. The FCC E-911 Phase-II requires wireless carriers to provide the location of a 911 caller with accuracy of 100 meters in 67% of cases and 300 meters in 95% of cases. This work proposes an information theoretic bound on mobile station (MS) localization performance in urban environments that provides an alternative criterion for the MS localization performance evaluation. The proposed lower bound provides necessary, but not sufficient conditions for achieving arbitrary small probability of the localization error. The MS localization problem is modeled in the framework of communication via channels where the source location is modeled as a transmitted message which is encoded by the propagation conditions. The bound is evaluated for variety of propagation conditions predicted by a recently proposed statistical model of urban propagation conditions. The bound is demonstrated to apply to urban scenes of interest, and the sensitivity of the bound to changes in propagation conditions is discussed.
IEEE Journal of Selected Topics in Signal Processing, 2021
Automotive imaging radars require high angular resolution which can be achieved by a large antenn... more Automotive imaging radars require high angular resolution which can be achieved by a large antenna aperture. In order to obey Nyquist spatial sampling rate, a large number of array elements and receive channels is required. In practice, this solution results in a prohibitively high cost and complexity. This work proposes a new cognitive receiver configuration, in which a large number of sensor array elements is connected to a small number of receive channels via a switching matrix. The state of the switching matrix is sequentially updated using information from previous observations and prior information. According to the proposed scheme, denoted as cognitive antenna selection (CASE), the state of the switching matrix is obtained by the minimization of conditional Bayesian bounds on the mean-squared-error of the direction-of-arrival estimate. We show that the Bayesian Cramér-Rao bound (BCRB) is an inappropriate optimization criterion since it ignores the effect of ambiguity. This wo...
2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), 2018
This paper describes optically semi-transparent and flexible microstrip interconnects and patch a... more This paper describes optically semi-transparent and flexible microstrip interconnects and patch antennas at millimeter wave frequencies. They are realized on a 5-mil thick transparent PET film by patterning honeycomb shape metal grids using a standard lithographic process. Dimensions of the employed metal grids were optimized for low insertion loss and >70% optical transmission at 77 GHz to enable integration into non-conventional surfaces for potential automotive radar applications. The fabricated microstrip lines demonstrate low-loss interconnects with <0.35dB/mm loss at 77 GHz and ~73% optical transmission from 390 nm to 700 nm. The fabricated semi-transparent microstrip patch antennas show radiation characteristics comparable to that made of standard solid metal.
2020 IEEE International Radar Conference (RADAR), 2020
A phased array antenna controls its beam steering direction by phase differences between signals ... more A phased array antenna controls its beam steering direction by phase differences between signals transmitted from multiple antenna elements. These phase differences are determined by antenna geometry and carrier frequency. Radars with phased array antennas, operating with frequency-modulated waveforms, suffer from beam steering direction errors, denoted as squint. This phenomenon and the resulting squint errors are especially significant in wide-band radars. This work proposes to utilize the nonlinear frequency-modulated Tansec waveform to compensate for the carrier frequency variation and thus, to mitigate beam squint. A method for Tansec waveforms selection is derived and its ability to mitigate beam squint is demonstrated via simulations.
2020 IEEE 11th Sensor Array and Multichannel Signal Processing Workshop (SAM), 2020
The emerging problem of automotive radars congestion is addressed in this work. Modern automotive... more The emerging problem of automotive radars congestion is addressed in this work. Modern automotive radars handle this problem via randomization of the transmit signal parameters. Alternatively, frequency allocation methods lead to narrow-band radar operation and as a result, reduced range resolution. This work proposes to mitigate the mutual interference between radars, while optimizing the localization performance by collaborative spectrum allocation and waveform design. According to the proposed approach, the transmit energy is allocated across the entire available spectrum by minimization of the Weiss-Weinstein bound. The proposed spectrum allocation approach allows to avoid frequencies occupied by interfering radars and the use of the entire spectrum allows to achieve the maximal possible resolution.
2012 6th European Conference on Antennas and Propagation (EUCAP), 2012
ABSTRACT This work address the channel capacity problem which is the key issue in the new generat... more ABSTRACT This work address the channel capacity problem which is the key issue in the new generation mobile broadband network. The simulation framework for analysis of channel capacity solution based on usage of the heterogeneous networks in complex urban and indoor environment is introduced in this work. The impact of heterogeneous network on channel capacity is analyzed based on proposed simulation framework. The multi-parametric statistical channel model is used for simulation of the propagation conditions. The advantages and drawbacks for various deployment strategies of femtocells in presence of macro coverage are investigated. It is shown that shared frequency assignment with open access gives better overall channel capacity for majority of the mobile outdoor and indoor users.
IEEE Transactions on Aerospace and Electronic Systems, 2021
Fast Fourier transform (FFT) is one of the fundamental signal processing algorithms widely used i... more Fast Fourier transform (FFT) is one of the fundamental signal processing algorithms widely used in radar applications. The Radon–Fourier transform (RFT) can be seen as an FFT generalization that can overcome some of its limitations. This work derives three spectral RFT (SRFT) based approaches to address major challenges of the multiple-input multiple-output automotive radars. First, two SRFT-based approaches are derived to increase maximal target detection range by mitigation of target migration in range and direction of arrival, jointly, and by multidwell integration processing, which increases the radar coherent integration time without compromising its detection update rate. Next, SRFT-based approach is proposed to address the cluster-to-track association problem that arises in multiple distributed target tracking scenarios that characterize automotive radar operation in dense urban environments.
2021 29th European Signal Processing Conference (EUSIPCO), 2021
Implementation of the intra-coding code-division multiple access (CDMA) multiple-input multiple-o... more Implementation of the intra-coding code-division multiple access (CDMA) multiple-input multiple-output (MIMO) radars requires orthogonality between the transmitted codewords. The lack of complete orthogonality between practical codewords induces sidelobes in the received signal which mask weak targets and increase probability of false alarm (PFA). This work proposes a novel and efficient CLEAN CDMA-MIMO approach, which considers all the transmitted codewords and the receiver noise coloring. The performance of the proposed approach is evaluated via simulations of a practical automotive scenario.
The high-resolution automotive radar is a key component in autonomous driving sensing suite. Vibr... more The high-resolution automotive radar is a key component in autonomous driving sensing suite. Vibration of the host vehicle degrades the automotive radar performance in terms of the maximal detection range and probability of false alarm. This work analyzes the effect of the vehicle vibration on the automotive radar and proposes a method for its mitigation. The performance of the proposed approach is evaluated using collected radar measurements and measured vibration. It is shown that the proposed approach succeeds in vibration effect mitigation even with vibration model mismatch.
IEEE Transactions on Aerospace and Electronic Systems, 2021
This work addresses code division multiple access (CDMA) implementation of automotive multiple-in... more This work addresses code division multiple access (CDMA) implementation of automotive multiple-input multiple-output (MIMO) radars. The tansec frequency modulation (TSFM) is proposed as a single intracoding scheme for CDMA-MIMO radars. The properties of the TSFM coding family are analyzed and two novel codeword selection algorithms are proposed. The TSFM is compared to a variety of coding families by evaluating their autocorrelation and cross-correlation properties. The considered coding families are based on phase coding: Hadamard, Gold, optimal peak to sidelobe; and frequency coding: piecewise linear frequency modulated. Properties of the coding families are analyzed with a variety of novel criteria, which are especially useful for CDMA-MIMO radars. The performance of the CDMA-MIMO radar with different coding families is evaluated via simulations of practical multitarget automotive scenarios. It is shown that the frequency-based TSFM coding family outperforms the other considered coding families in terms of their cross-correlation properties.
2010 IEEE Sensor Array and Multichannel Signal Processing Workshop, 2010
The FCC E-911 Phase-2 requirements have motivated increased interest in the challenge of localizi... more The FCC E-911 Phase-2 requirements have motivated increased interest in the challenge of localizing mobile sources in a dense urban environment. E-911 Phase-2 requires wireless carriers to provide the location of a 911 caller with accuracy of 100 meters in 67% of cases and 300 meters in 95% of cases. This paper proposes information theoretic bounds on source localization performance in a dense urban environment based on the distribution of received energy as a function of time and angle of arrival from the multipath propagation. The surveillance area is discretized into a grid of partitions where the partition size can be interpreted as a source localization accuracy. The proposed lower bound provides a limit on the achievable source localization accuracy for a given SNR. The bound is evaluated for several urban propagation scenarios.
This work addresses the probability of detection problem and false alarm performance degradation ... more This work addresses the probability of detection problem and false alarm performance degradation in automotive radar scenarios with multipath induced ghost targets. A novel multipath mitigation method which evaluates correlation between the target and its hypothesized ghost tracks, is proposed. The performance of the proposed method is evaluated with simulations and by using collected radar measurements, in practical scenes of moving target vehicles in adjacency to flat reflective surface.
The Journal of the Acoustical Society of America, 2012
The big brown bat (Eptesicus fuscus) uses frequency modulated (FM) echolocation calls to accurate... more The big brown bat (Eptesicus fuscus) uses frequency modulated (FM) echolocation calls to accurately estimate range and resolve closely spaced objects in clutter and noise. They resolve glints spaced down to 2 μs in time delay which surpasses what traditional signal processing techniques can achieve using the same echolocation call. The Matched Filter (MF) attains 10-12 μs resolution while the Inverse Filter (IF) achieves higher resolution at the cost of significantly degraded detection performance. Recent work by Fontaine and Peremans [J. Acoustic. Soc. Am. 125, 3052-3059 (2009)] demonstrated that a sparse representation of bat echolocation calls coupled with a decimating sensing method facilitates distinguishing closely spaced objects over realistic SNRs. Their work raises the intriguing question of whether sensing approaches structured more like a mammalian auditory system contains the necessary information for the hyper-resolution observed in behavioral tests. This research estimates sparse echo signatures using a gammatone filterbank decimation sensing method which loosely models the processing of the bat&amp;amp;amp;amp;amp;amp;amp;amp;#39;s auditory system. The decimated filterbank outputs are processed with [script-l](1) minimization. Simulations demonstrate that this model maintains higher resolution than the MF and significantly better detection performance than the IF for SNRs of 5-45 dB while undersampling the return signal by a factor of six.
IEEE Transactions on Aerospace and Electronic Systems, 2010
ABSTRACT The problem of sequential Bayesian estimation in linear non-Gaussian problems is address... more ABSTRACT The problem of sequential Bayesian estimation in linear non-Gaussian problems is addressed. In the Gaussian sum filter (GSF), the non-Gaussian system noise, the measurement noise, and the posterior state densities are modeled by the Gaussian mixture model (GMM). The GSF is optimal under the minimum-mean-square error (MMSE) criterion, however it is impractical due to the exponential model order growth of the system probability density function (pdf). The proposed recursive estimator, named the Gaussian mixture Kalman filter (GMKF), combines the GSF and the model order reduction procedure. The posterior state density at each iteration is approximated by a lower order density. This model order reduction procedure minimizes the estimated Kullback-Leibler divergence (KLD) of the reduced order density from the original density at each step. The estimation performance of the proposed GMKF is compared with the interactive multiple modeling (IMM), particle filter (PF), Gaussian sum PF (GSPF), and the GSF with mixture reduction (MR) method via simulations. It is shown in several examples that the proposed GMKF outperforms the other tested algorithms in terms of estimation accuracy. The superior estimation performance of the GMKF is obtained at the expense of its computational complexity, which is higher than the IMM and the MR algorithms.
Page 1. .:. TECHNICAL PAPER REVIEW COMMITTEE The Technical Program Committee Chairs wish to thank... more Page 1. .:. TECHNICAL PAPER REVIEW COMMITTEE The Technical Program Committee Chairs wish to thank all of the Review Committee Members for their support Raviraj Adve Maria Greco Eric Mokole Fauzia Ahmad Marshall Greenspan Alberto Moreira Geoffrey Akers Hugh Griffiths Anders Nelander Chris Allen Joseph Guerci Xavier Neyt Richard Bamler Svein-Erik Hamran Trung Nguyen Jamie Bergin Ryan Hersey Yoann Paichard Igal Bilik Thomas Higgins James Palmer William Blair Braham Himed Jason Parker ...
ABSTRACT The Federal Communications Commission (FCC) Phase II enhanced 911 (E-911) requirements h... more ABSTRACT The Federal Communications Commission (FCC) Phase II enhanced 911 (E-911) requirements have motivated increased interest in the challenge of localizing mobile sources in urban environments. The FCC E-911 Phase-II requires wireless carriers to provide the location of a 911 caller with accuracy of 100 meters in 67% of cases and 300 meters in 95% of cases. This work proposes an information theoretic bound on mobile station (MS) localization performance in urban environments that provides an alternative criterion for the MS localization performance evaluation. The proposed lower bound provides necessary, but not sufficient conditions for achieving arbitrary small probability of the localization error. The MS localization problem is modeled in the framework of communication via channels where the source location is modeled as a transmitted message which is encoded by the propagation conditions. The bound is evaluated for variety of propagation conditions predicted by a recently proposed statistical model of urban propagation conditions. The bound is demonstrated to apply to urban scenes of interest, and the sensitivity of the bound to changes in propagation conditions is discussed.
IEEE Journal of Selected Topics in Signal Processing, 2021
Automotive imaging radars require high angular resolution which can be achieved by a large antenn... more Automotive imaging radars require high angular resolution which can be achieved by a large antenna aperture. In order to obey Nyquist spatial sampling rate, a large number of array elements and receive channels is required. In practice, this solution results in a prohibitively high cost and complexity. This work proposes a new cognitive receiver configuration, in which a large number of sensor array elements is connected to a small number of receive channels via a switching matrix. The state of the switching matrix is sequentially updated using information from previous observations and prior information. According to the proposed scheme, denoted as cognitive antenna selection (CASE), the state of the switching matrix is obtained by the minimization of conditional Bayesian bounds on the mean-squared-error of the direction-of-arrival estimate. We show that the Bayesian Cramér-Rao bound (BCRB) is an inappropriate optimization criterion since it ignores the effect of ambiguity. This wo...
2018 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM), 2018
This paper describes optically semi-transparent and flexible microstrip interconnects and patch a... more This paper describes optically semi-transparent and flexible microstrip interconnects and patch antennas at millimeter wave frequencies. They are realized on a 5-mil thick transparent PET film by patterning honeycomb shape metal grids using a standard lithographic process. Dimensions of the employed metal grids were optimized for low insertion loss and >70% optical transmission at 77 GHz to enable integration into non-conventional surfaces for potential automotive radar applications. The fabricated microstrip lines demonstrate low-loss interconnects with <0.35dB/mm loss at 77 GHz and ~73% optical transmission from 390 nm to 700 nm. The fabricated semi-transparent microstrip patch antennas show radiation characteristics comparable to that made of standard solid metal.
2020 IEEE International Radar Conference (RADAR), 2020
A phased array antenna controls its beam steering direction by phase differences between signals ... more A phased array antenna controls its beam steering direction by phase differences between signals transmitted from multiple antenna elements. These phase differences are determined by antenna geometry and carrier frequency. Radars with phased array antennas, operating with frequency-modulated waveforms, suffer from beam steering direction errors, denoted as squint. This phenomenon and the resulting squint errors are especially significant in wide-band radars. This work proposes to utilize the nonlinear frequency-modulated Tansec waveform to compensate for the carrier frequency variation and thus, to mitigate beam squint. A method for Tansec waveforms selection is derived and its ability to mitigate beam squint is demonstrated via simulations.
2020 IEEE 11th Sensor Array and Multichannel Signal Processing Workshop (SAM), 2020
The emerging problem of automotive radars congestion is addressed in this work. Modern automotive... more The emerging problem of automotive radars congestion is addressed in this work. Modern automotive radars handle this problem via randomization of the transmit signal parameters. Alternatively, frequency allocation methods lead to narrow-band radar operation and as a result, reduced range resolution. This work proposes to mitigate the mutual interference between radars, while optimizing the localization performance by collaborative spectrum allocation and waveform design. According to the proposed approach, the transmit energy is allocated across the entire available spectrum by minimization of the Weiss-Weinstein bound. The proposed spectrum allocation approach allows to avoid frequencies occupied by interfering radars and the use of the entire spectrum allows to achieve the maximal possible resolution.
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Papers by Igal Bilik