The Experts below are selected from a list of 4704 Experts worldwide ranked by ideXlab platform
Braham Himed - One of the best experts on this subject based on the ideXlab platform.
-
a dual function MIMO Radar communications system using frequency hopping waveforms
IEEE Radar Conference, 2017Co-Authors: Aboulnasr Hassanien, Braham Himed, Brian D RiglingAbstract:The dual use of radio signals for simultaneous operation of Radar and communications has recently attracted significant interest. In this paper, we develop a method for information embedding into the emission of multiple-input multiple-output (MIMO) Radar using frequency-hopping (FH) waveforms. The set of orthogonal waveforms used to implement the primary MIMO Radar operation is generated using FH codes. The secondary communication function is implemented by embedding one phase-shift keying (PSK) communication symbol in each frequency hop, i.e., the number of embedded communication symbols during each Radar pulse equals the number of transmit antennas times the length of the FH code. We show that the communication operation is transparent to the MIMO Radar function of the dual-function system. Standard ratio testing is used to detect the embedded PSK symbols at the communication receiver. The achievable data rate is proportional to the pulse repetition frequency, the number of transmit elements, the length of the FH code, and the size of the PSK constellation. The performance of the proposed technique is investigated in terms of the symbol error rate.
-
waveform optimization for transmit beamforming with MIMO Radar antenna arrays
IEEE Transactions on Antennas and Propagation, 2015Co-Authors: Lilin Guo, Hai Deng, Braham Himed, Zhe GengAbstract:For coherent MIMO Radar the optimal target signal processing can be achieved for any transmitted waveforms or radiation beam pattern, making transmit beamforming through waveform design possible without degrading target detection performance. In this work, an innovative waveform optimization approach termed phase-only variable metric method (POVMM) is proposed for coherent MIMO Radar waveform design to form a desired transmit beam pattern such as one with radiation nulls in certain directions. The waveform design is carried out by minimizing the radiation powers of the MIMO Radar antenna in the selected directions with optimization variables constrained to the waveform phases only. The gradient function of the cost function with regard to waveform phases is analytically derived for the optimization and the POVMM is developed based on the variable metric methods with a flexible search step sizing strategy for improving optimization efficiency. The proposed approach is validated with various designs and simulations.
-
detection in passive MIMO Radar networks
IEEE Transactions on Signal Processing, 2014Co-Authors: Daniel E Hack, Lee K. Patton, Braham Himed, Michael A SavilleAbstract:This paper addresses target detection in passive multiple-input multiple-output (MIMO) Radar networks comprised of non-cooperative transmitters and multichannel receivers. A generalized likelihood ratio test is derived, and approximate test statistic distributions are presented for both hypotheses under common scenario conditions. Analysis and simulation results show that this detector outperforms other passive MIMO Radar detectors because it exploits more correlations within the measurement data. This detector is also compared against related detectors for active MIMO Radar and passive source localization sensor networks. These comparisons reveal that passive MIMO Radar detection performance varies between active MIMO Radar and passive source localization detection performance as a function of direct-path signal quality. Therefore, passive MIMO Radar unifies active MIMO Radar and passive source localization sensor networks in a common theoretical framework.
-
moving target detection using distributed MIMO Radar in clutter with nonhomogeneous power
IEEE Transactions on Signal Processing, 2011Co-Authors: Pu Wang, Braham HimedAbstract:In this paper, we consider moving target detection using a distributed multiple-input multiple-output (MIMO) Radar on stationary platforms in nonhomogeneous clutter environments. Our study is motivated by the fact that the multistatic transmit-receive configuration in a distributed MIMO Radar causes nonstationary clutter. Specifically, the clutter power for the same test cell may vary significantly from one transmit-receive pair to another, due to azimuth-selective backscattering of the clutter. To account for these issues, a new nonhomogeneous clutter model, where the clutter resides in a low-rank subspace with different subspace coefficients (and hence different clutter power) for different transmit-receive pair, is introduced and the relation to a general clutter model is discussed. Following the proposed clutter model, we develop a generalized-likelihood ratio test (GLRT) for moving target detection in distributed MIMO Radar. The GLRT is shown to be a constant false alarm rate (CFAR) detector, and the test statistic is a central and noncentral Beta variable under the null and alternative hypotheses, respectively. Simulations are provided to demonstrate the performance of the proposed GLRT in comparison with several existing techniques.
Aboulnasr Hassanien - One of the best experts on this subject based on the ideXlab platform.
-
a dual function MIMO Radar communications system using frequency hopping waveforms
IEEE Radar Conference, 2017Co-Authors: Aboulnasr Hassanien, Braham Himed, Brian D RiglingAbstract:The dual use of radio signals for simultaneous operation of Radar and communications has recently attracted significant interest. In this paper, we develop a method for information embedding into the emission of multiple-input multiple-output (MIMO) Radar using frequency-hopping (FH) waveforms. The set of orthogonal waveforms used to implement the primary MIMO Radar operation is generated using FH codes. The secondary communication function is implemented by embedding one phase-shift keying (PSK) communication symbol in each frequency hop, i.e., the number of embedded communication symbols during each Radar pulse equals the number of transmit antennas times the length of the FH code. We show that the communication operation is transparent to the MIMO Radar function of the dual-function system. Standard ratio testing is used to detect the embedded PSK symbols at the communication receiver. The achievable data rate is proportional to the pulse repetition frequency, the number of transmit elements, the length of the FH code, and the size of the PSK constellation. The performance of the proposed technique is investigated in terms of the symbol error rate.
-
towards a dual function MIMO Radar communication system
IEEE Radar Conference, 2016Co-Authors: Elie Boudaher, Aboulnasr Hassanien, Elias Aboutanios, Moeness G AminAbstract:Recently, dual-function Radar-communication systems in which the Radar platform and resources are used for communication signal embedding have emerged as means to alleviate spectrum congestion and ease competition over frequency bandwidth. In this paper, we introduce a new technique for information embedding specific to multiple-input multiple output (MIMO) Radar. We exploit the fact that in a MIMO Radar system, the receiver needs to know the association of the transmit waveforms to the transmit antennas. However, this association can change over different pulse repetition periods without impacting the Radar functionality. We show that by shuffling the waveforms across the transmit antennas over constant pulse repetition periods, a data rate of megabits per second can be achieved for a moderate number of transmit antennas. The probability of error is analyzed and the bounds on the symbol error rate are derived. Simulation examples are provided for performance evaluation and to demonstrate the effectiveness of the proposed information embedding technique.
-
robust beamforming for jammers suppression in MIMO Radar
IEEE Radar Conference, 2014Co-Authors: Sergiy A Vorobyov, Aboulnasr HassanienAbstract:Robust beamforming for multiple-input multiple-output (MIMO) Radar in the background of powerful jamming signals is investigated in this paper. We design two minimum variance distortionless response (MVDR) type beamformers with adaptiveness/robustness against the powerful jammers for colo-cated MIMO Radar. Specifically, the MVDR beamformer is firstly designed for known jammers in the sector-of-interest, which maintains distortionless response towards the direction of the target while imposing nulls towards the directions of jammers. Then the adaptive/robust MVDR beamformer is designed for the general case of unknown in-sector jammers and/or out-of-sector interfering sources. Convex optimization techniques are used in both of the designs. Moreover, we derive a closed-form solution to the simplified second design. Based on this solution, we derive efficient power estimates of the desired and/or interfering sources in the context of powerful jammers and non-ideal factors such as array calibration errors and target steering vector mismatches. We demonstrate that the capability of efficient jammers suppression using these designs is unique in MIMO Radar.
-
MIMO Radar capability on powerful jammers suppression
International Conference on Acoustics Speech and Signal Processing, 2014Co-Authors: Sergiy A Vorobyov, Aboulnasr HassanienAbstract:The problem of jammers suppression in colocated multiple-input multiple-output (MIMO) Radar is considered. We resort to reduced dimension (RD) beamspace designs with robust-ness/adaptiveness to achieve the goal of efficient jammers suppression. Specifically, our RD beamspace techniques aim at designing optimal beamspace matrices based on reasonable tradeoffs between the desired in-sector source distortion and the powerful jammer (possibly in-sector) attenuation when conducting the jammers suppression. These designs are cast as convex optimization problems which are derived using second-order cone programming. Meanwhile, we study the MUSIC-based direction-of-arrival estimation performance of the proposed beamspace designs by comparing to the conventional algorithms. Moreover, we demonstrate that the capability of efficient powerful in-sector jammers suppression using these designs is unique in MIMO Radar.
-
subspace based direction finding using transmit energy focusing in MIMO Radar with colocated antennas
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Aboulnasr Hassanien, Sergiy A VorobyovAbstract:In this paper, we consider the problem of direction finding in multiple-input multiple-output (MIMO) Radar based on focusing the transmitted pulse energy within certain spatial sector(s). We propose a method for designing the transmit weight matrix based on maximizing the energy transmitted within the desired spatial sector and minimizing the energy disseminated in the out-of-sector area. The proposed transmit energy focusing results in the signal-to-noise ratio increase at the receive array which in turn leads to lower Cramer-Rao bound and improved direction of arrival estimation performance. Simulation results show the substantial improvements offered by the proposed transmit energy focusing based MIMO Radar as compared to the traditional MIMO Radar and the MIMO Radar with receive beamspace post-processing.
Rick S. Blum - One of the best experts on this subject based on the ideXlab platform.
-
some phase synchronization algorithms for coherent MIMO Radar
Conference on Information Sciences and Systems, 2011Co-Authors: Yang Yang, Rick S. BlumAbstract:Practical realization of the coherent processing in widely separated multiple-input multiple-output (MIMO) Radar systems requires the development of implementable techniques to ensure a common notion of phase among all the distributed Radar elements. In this work, we present two effective approaches to achieve phase synchronization in coherent MIMO Radar systems. The first one is the master-slave closed-loop approach, which employs a master-slave architecture. This method is very simple, and is particularly suitable for fine phase synchronization. The second one is the round-trip algorithm, which employs an unmodulated beacon signal to travel through all the Radar elements in a round-trip manner. These algorithms are both time asynchronous in nature, and they require no a priori establishment of either time or frequency synchronization. Under a similar analytical framework, we mathematically characterize each of these algorithms, and further derive and analyze the statistical properties of the corresponding phase synchronization error.
-
Phase synchronization for coherent MIMO Radar: Algorithms and their analysis
IEEE Transactions on Signal Processing, 2011Co-Authors: Yang Yang, Rick S. BlumAbstract:Multiple-input multiple-output (MIMO) Radar can achieve improved localization performance by employing a coherent processing approach with proper antenna positioning. Coherent processing, however, entails the challenge of ensuring phase coherence of the carrier signals from different distributed Radar elements. In this work, we aim to address such a challenge by providing a systematic treatment of the phase synchronization problem in coherent MIMO Radar systems. We propose and study three different approaches for reaching a common notion of phase in coherent MIMO Radar, namely, the master-slave closed-loop algorithm, the round-trip algorithm and the broadcast consensus based algorithm. These algorithms range from centralized to distributed types, and include both noniterative and iterative approaches. They do not require a priori establishment of the time synchronization, and thus are all time asynchronous in nature. Under a similar analytical framework, we mathematically characterize each of these algorithms, and further derive and study the statistical properties of a few relevant figures of merit including the resulting phase synchronization error. Simulation results are presented to validate our theoretical analysis.
-
MIMO Radar moving target detection in homogeneous clutter
IEEE Transactions on Aerospace and Electronic Systems, 2010Co-Authors: Qian He, Nikolaus H Lehmann, Rick S. Blum, Alexander M. HaimovichAbstract:A multiple-input multiple-output (MIMO) Radar approach employing widely dispersed transmit and receive antennas is studied for the detection of moving targets. The MIMO Radar transmits orthogonal waveforms from the different transmit antennas so these waveforms can be separated at each receive antenna. For a moving target in colored Gaussian noise-plus-clutter, we quantify the gains from having widely dispersed antennas that allow the overall system to "view" the target simultaneously from several different directions. The MIMO Radar performance is contrasted with that of a traditional phased-array approach, which employs closely spaced antennas for this purpose. The MIMO Radar approach is well suited to handle targets that have small radial velocities for scenarios in which colocated sensors cannot separate the target from the background clutter. Both a centralized processing and a simple distributed processing form of the MIMO Radar approach are developed and studied, and the gains from the centralized version, which come at the price of additional complexity, are clearly demonstrated and explained intuitively. The constant false alarm rate (CFAR) property of an adaptive version of the MIMO moving target detector is also demonstrated for homogeneous clutter.
-
concepts and applications of a MIMO Radar system with widely separated antennas
MIMO Radar Signal Processing, 2009Co-Authors: Hana Godrich, Alexander M. Haimovich, Rick S. BlumAbstract:This chapter contains sections titled: Background MIMO Radar Concept NonCoherent MIMO Radar Applications Coherent MIMO Radar Applications Chapter Summary Appendix 9A Deriving the FIM Appendix 9B Deriving the CRLB on the Location Estimate Error Appendix 9C MLE of Time Delays ??????-?????? Error Statistics Appendix 9D Deriving the Lowest GDOP for Special Cases Acknowledgments References
-
MIMO Radar with widely separated antennas
IEEE Signal Processing Magazine, 2008Co-Authors: Alexander M. Haimovich, Rick S. Blum, Leonardo J. CiminiAbstract:MIMO (multiple-input multiple-output) Radar refers to an architecture that employs multiple, spatially distributed transmitters and receivers. While, in a general sense, MIMO Radar can be viewed as a type of multistatic Radar, the separate nomenclature suggests unique features that set MIMO Radar apart from the multistatic Radar literature and that have a close relation to MIMO communications. This article reviews some recent work on MIMO Radar with widely separated antennas. Widely separated transmit/receive antennas capture the spatial diversity of the target's Radar cross section (RCS). Unique features of MIMO Radar are explained and illustrated by examples. It is shown that with noncoherent processing, a target's RCS spatial variations can be exploited to obtain a diversity gain for target detection and for estimation of various parameters, such as angle of arrival and Doppler. For target location, it is shown that coherent processing can provide a resolution far exceeding that supported by the Radar's waveform.
Arye Nehorai - One of the best experts on this subject based on the ideXlab platform.
-
gridless parameter estimation for one bit MIMO Radar with time varying thresholds
IEEE Transactions on Signal Processing, 2020Co-Authors: Yijian Xiang, Shengyao Chen, Arye NehoraiAbstract:We investigate the one-bit MIMO (1b-MIMO) Radar that performs one-bit sampling with a time-varying threshold in the temporal domain and employs compressive sensing in the spatial and Doppler domains. The goals are to significantly reduce the hardware cost, energy consumption, and amount of stored data. The joint angle and Doppler frequency estimations from noisy one-bit data are studied. By showing that the effect of noise on one-bit sampling is equivalent to that of sparse impulsive perturbations, we formulate the one-bit $\ell _1$ -regularized atomic-norm minimization (1b-ANM-L1) problem to achieve gridless parameter estimation with high accuracy. We also develop an iterative method for solving the 1b-ANM-L1 problem via the alternating direction method of multipliers. The Cram $\acute{\text{e}}$ r-Rao bound (CRB) of the 1b-MIMO Radar is analyzed, and the analytical performance of one-bit sampling with two different threshold strategies is discussed. Numerical experiments are presented to show that the 1b-MIMO Radar can achieve high-resolution parameter estimation with a largely reduced amount of data.
-
jointly optimal design for MIMO Radar frequency hopping waveforms using game theory
IEEE Transactions on Aerospace and Electronic Systems, 2016Co-Authors: Keyong Han, Arye NehoraiAbstract:Using a colocated multiple input/multiple output (MIMO) Radar system, we consider the problem of joint design of amplitudes and frequency-hopping codes for frequency-hopping waveforms. The joint design method yields better combined code and amplitude matrices that result in improved performance over that of separate designs. We propose a game theory framework for the joint design. First, we present the MIMO Radar signal model and the sparse representation. Then the problem formulation is constructed based on sparse recovery and the ambiguity function of the MIMO Radar system for frequency-hopping waveforms. For amplitude design, we propose two strategies: amplitude design with separate constraints and amplitude design by fusing all transmitters. We formulate a novel game model and propose two joint design algorithms, one applying a noncooperative scheme and the other applying a cooperative scheme. Owing to the extremely large size of the feasible set of the discrete code, we propose to use these algorithms to obtain the є-approximate equilibrium. We demonstrate the improvement of the resulting codes and amplitudes through numerical examples.
-
target estimation using sparse modeling for distributed MIMO Radar
IEEE Transactions on Signal Processing, 2011Co-Authors: Sandeep Gogineni, Arye NehoraiAbstract:Multiple-input multiple-output (MIMO) Radar systems with widely separated antennas provide spatial diversity by viewing the targets from different angles. In this paper, we use a novel approach to accurately estimate properties (position, velocity) of multiple targets using such systems by employing sparse modeling. We also introduce a new metric to analyze the performance of the Radar system. We propose an adaptive mechanism for optimal energy allocation at the different transmit antennas. We show that this adaptive energy allocation mechanism significantly improves in performance over MIMO Radar systems that transmit fixed equal energy across all the antennas. We also demonstrate accurate reconstruction from very few samples by using compressive sensing at the receivers.
Sergiy A Vorobyov - One of the best experts on this subject based on the ideXlab platform.
-
robust beamforming for jammers suppression in MIMO Radar
IEEE Radar Conference, 2014Co-Authors: Sergiy A Vorobyov, Aboulnasr HassanienAbstract:Robust beamforming for multiple-input multiple-output (MIMO) Radar in the background of powerful jamming signals is investigated in this paper. We design two minimum variance distortionless response (MVDR) type beamformers with adaptiveness/robustness against the powerful jammers for colo-cated MIMO Radar. Specifically, the MVDR beamformer is firstly designed for known jammers in the sector-of-interest, which maintains distortionless response towards the direction of the target while imposing nulls towards the directions of jammers. Then the adaptive/robust MVDR beamformer is designed for the general case of unknown in-sector jammers and/or out-of-sector interfering sources. Convex optimization techniques are used in both of the designs. Moreover, we derive a closed-form solution to the simplified second design. Based on this solution, we derive efficient power estimates of the desired and/or interfering sources in the context of powerful jammers and non-ideal factors such as array calibration errors and target steering vector mismatches. We demonstrate that the capability of efficient jammers suppression using these designs is unique in MIMO Radar.
-
MIMO Radar capability on powerful jammers suppression
International Conference on Acoustics Speech and Signal Processing, 2014Co-Authors: Sergiy A Vorobyov, Aboulnasr HassanienAbstract:The problem of jammers suppression in colocated multiple-input multiple-output (MIMO) Radar is considered. We resort to reduced dimension (RD) beamspace designs with robust-ness/adaptiveness to achieve the goal of efficient jammers suppression. Specifically, our RD beamspace techniques aim at designing optimal beamspace matrices based on reasonable tradeoffs between the desired in-sector source distortion and the powerful jammer (possibly in-sector) attenuation when conducting the jammers suppression. These designs are cast as convex optimization problems which are derived using second-order cone programming. Meanwhile, we study the MUSIC-based direction-of-arrival estimation performance of the proposed beamspace designs by comparing to the conventional algorithms. Moreover, we demonstrate that the capability of efficient powerful in-sector jammers suppression using these designs is unique in MIMO Radar.
-
subspace based direction finding using transmit energy focusing in MIMO Radar with colocated antennas
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Aboulnasr Hassanien, Sergiy A VorobyovAbstract:In this paper, we consider the problem of direction finding in multiple-input multiple-output (MIMO) Radar based on focusing the transmitted pulse energy within certain spatial sector(s). We propose a method for designing the transmit weight matrix based on maximizing the energy transmitted within the desired spatial sector and minimizing the energy disseminated in the out-of-sector area. The proposed transmit energy focusing results in the signal-to-noise ratio increase at the receive array which in turn leads to lower Cramer-Rao bound and improved direction of arrival estimation performance. Simulation results show the substantial improvements offered by the proposed transmit energy focusing based MIMO Radar as compared to the traditional MIMO Radar and the MIMO Radar with receive beamspace post-processing.
-
phased MIMO Radar a tradeoff between phased array and MIMO Radars
IEEE Transactions on Signal Processing, 2010Co-Authors: Aboulnasr Hassanien, Sergiy A VorobyovAbstract:We propose a new technique for multiple-input multiple-output (MIMO) Radar with colocated antennas which we call phased-MIMO Radar. The new technique enjoys the advantages of the MIMO Radar without sacrificing the main advantage of the phased-array Radar which is the coherent processing gain at the transmitting side. The essence of the proposed technique is to partition the transmit array into a number of subarrays that are allowed to overlap. Then, each subarray is used to coherently transmit a waveform which is orthogonal to the waveforms transmitted by other subarrays. Coherent processing gain can be achieved by designing a weight vector for each subarray to form a beam towards a certain direction in space. Moreover, the subarrays are combined jointly to form a MIMO Radar resulting in higher angular resolution capabilities. Substantial improvements offered by the proposed phased-MIMO Radar technique as compared to the phased-array and MIMO Radar techniques are demonstrated analytically and by simulations through analyzing the corresponding beam patterns and the achievable output signal-to-noise-plus-interference ratios. Both analytical and simulation results validate the effectiveness of the proposed phased-MIMO Radar.
-
transmit receive beamforming for MIMO Radar with colocated antennas
International Conference on Acoustics Speech and Signal Processing, 2009Co-Authors: Aboulnasr Hassanien, Sergiy A VorobyovAbstract:We propose a new technique for multiple-input multiple-output (MIMO) Radar with colocated antennas. The essence of the proposed technique is to partition the transmitting array into a number of subarrays that are allowed to overlap. Each subarray is used to coherently transmit a waveform which is orthogonal to the waveforms transmitted by other subarrays. Coherent processing gain can be achieved by designing a weight vector for each subarray to form a beam towards a certain direction in space. Moreover, the subarrays are combined jointly to form a MIMO Radar resulting in higher resolution capabilities. Simulation results show the substantial improvements offered by the proposed technique as compared to previous techniques that validate its effectiveness.