In this paper, we develop a new class of time division multiple access schemes for bi-directional multiuser communications in cooperative amplify-and-forward relay networks. the proposed schemes enable a flexible trad...
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In this paper, we develop a new class of time division multiple access schemes for bi-directional multiuser communications in cooperative amplify-and-forward relay networks. the proposed schemes enable a flexible trade-off between spectral efficiency and suppression of multiuser interference. the relay weights are chosen to maximize the minimum received quality-of-service of all the users under constraints on the individual and the total power at the relays. Simulation results demonstrate that the selection of the scheme has a considerable impact on the achieved throughput of the relay network.
In this paper, random switch antenna array (RSAA) is proposed to apply to the switch antenna array (SAA) frequency-modulated continuous-wave (FMCW) radar system. Firstly, the signal model and signalprocessing method ...
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ISBN:
(纸本)9781467310703
In this paper, random switch antenna array (RSAA) is proposed to apply to the switch antenna array (SAA) frequency-modulated continuous-wave (FMCW) radar system. Firstly, the signal model and signalprocessing method of RSAA is analyzed and it shows that RSAA can successfully solve azimuth-velocity coupling problem. then we suppose a method by using RSAA to reduce the switching frequency and sampling rate based on sparse signal representation with multiple measurement vectors (MMV). It is shown in simulations that the proposed algorithms yield better performance in terms of azimuth-velocity decoupling and can obtain high image accuracy with less observation data.
An adaptive algorithm for azimuth-angle estimation of moving sources in the presence of array nonidealities is proposed. the method, termed unitary element-space Capon (UESCapon) beamformer, is robust in the face of s...
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An adaptive algorithm for azimuth-angle estimation of moving sources in the presence of array nonidealities is proposed. the method, termed unitary element-space Capon (UESCapon) beamformer, is robust in the face of small number of snapshots and fully takes into account effects such as mutual coupling, mounting platform reflections, and sensor's misplacement errors. Unlike most of the robust beamformers available in the literature, the proposed method is based on QR-decomposition and real-valued polynomial root tracking. Furthermore, it is applicable to sensorarrays of arbitrary configuration. Numerical results using a real-world antenna array are included, illustrating the excellent performance of the proposed method, both in terms of SINR and fast adaptivity to moving sources.
Over the last decade, several robust adaptive receive beamformers based on covariance matrix fitting (CMF) techniques have been proposed. For these beamformers, the estimate of the signal steering vector is first matc...
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Over the last decade, several robust adaptive receive beamformers based on covariance matrix fitting (CMF) techniques have been proposed. For these beamformers, the estimate of the signal steering vector is first matched to the sample covariance matrix. Subsequently, the minimum variance distortionless response beamformer weight vector is computed using the matched vector. the CMF problems are formulated using uncertainty sets for the signal steering vector. However, the signal steering vector is typically non-identifiable if only an uncertainty set for this vector and the array covariance matrix are known. In this paper, we numerically analyze the impact of this non-identifiability on the performance of CMF based beamformers.
this paper describes a method for detecting and tracking multiple moving targets using a multistatic narrowband radar sensorarray. We show that the appropriate model for the sensorarray measurements is non-linear an...
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this paper describes a method for detecting and tracking multiple moving targets using a multistatic narrowband radar sensorarray. We show that the appropriate model for the sensorarray measurements is non-linear and the statistics are non-Gaussian. We use this model in conjunction with a Bayesian estimation algorithm which constructs a probability density on the number of targets and their states. the density is approximated using a novel hybrid discrete grid/particle filter. We evaluate the performance on a set of experimental data from a 6-channel array to detect and track two targets that cross, make sharp turns, and move nearly cross-radially to some pairs for a significant portion of the collect.
the authors examine a technique to apply coherent signal subspace processing in the beam-space of a bank of true time delay beamformers. the technique is shown to be capable of resolving closely spaced sources while b...
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the authors examine a technique to apply coherent signal subspace processing in the beam-space of a bank of true time delay beamformers. the technique is shown to be capable of resolving closely spaced sources while being inherently wideband in nature, computationally less expensive than many previous wideband coherent integration techniques, and does not rely on a preliminary angle of arrival estimate. the technique is examined for performance with various levels of noise in the system compared to previous methods and the Cramer-Rao theoretical performance bound.
Current systems for multi-channel underwater signalprocessing suffer from a tied relation between the hardware and physical layer software or require a large amount of engineering work. To provide a low-cost, small f...
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Current systems for multi-channel underwater signalprocessing suffer from a tied relation between the hardware and physical layer software or require a large amount of engineering work. To provide a low-cost, small form factor and flexible solution, this work presents a multi-channel testbed consisting of an off-the-shelf FPGA board and a simple expansion board. Nonetheless, the proposed testbed provides the flexibility and processing power to evaluate novel multi-channel physical layer algorithms.
In this work, we propose a distributed power control algorithm able to capture the tradeoff between detection capabilities and power consumption for a radar sensor network. this is achieved by modeling the radar senso...
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In this work, we propose a distributed power control algorithm able to capture the tradeoff between detection capabilities and power consumption for a radar sensor network. this is achieved by modeling the radar sensors as rational agents engaging in a noncooperative game in which the detection threshold and the transmit power are properly designed according to the Nash equilibrium solution. An iterative algorithm based on a best-response dynamics is proposed to achieve the equilibrium point and its performance is compared to that achieved by a uniform power allocation.
PATENT PENDING. Time-of-arrival (TOA) localization is tightly coupled withsensor time synchronization. Synchronization can be obtained by GPS, atomic clocks or message exchange protocols. All methods affect the energ...
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PATENT PENDING. Time-of-arrival (TOA) localization is tightly coupled withsensor time synchronization. Synchronization can be obtained by GPS, atomic clocks or message exchange protocols. All methods affect the energy sources and the synchronization protocols use valuable bandwidth. We present self-synchronized localization algorithms that rely exclusively on TOA measurements performed by the sensor network on passing sources rendering it completely passive. Localization performance is close to that provided by a perfectly synchronized network. Such algorithms can also be used for sensor network synchronization and communication networks in general.
Space-time adaptive processing (STAP) is used in radar to adaptively suppress both ground clutter returns and radio frequency interference (RFI). However, RFI suppression utilizes degrees-of-freedom that would otherwi...
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Space-time adaptive processing (STAP) is used in radar to adaptively suppress both ground clutter returns and radio frequency interference (RFI). However, RFI suppression utilizes degrees-of-freedom that would otherwise be applied to clutter suppression. this paper considers designing the transmit pulse so that fast-time correlated (i.e., colored) RFI is suppressed in the pulse-compression stage preceding the STAP processor. the objective function and constraints for the waveform optimization are derived, and a numerical example demonstrating the efficacy of the approach is provided.
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