Channel estimation is always implemented in communication systems to overcome the effect of interference and noise. Especially, in wireless communications, this task is more challenging to improve system performance w...
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ISBN:
(纸本)9781665452458
Channel estimation is always implemented in communication systems to overcome the effect of interference and noise. Especially, in wireless communications, this task is more challenging to improve system performance while saving resources. This paper focuses on investigating the impact of geometries of antennaarrays on the performance of structured channel estimation in massive MIMO-OFDM systems. We use Cram ' er Rao Bound to analyze errors in two methods, i.e., training-based and semi-blind-based channel estimations. The simulation results show that the latter gets significantly better performance than the former. Besides, the system with Uniform Cylindrical array outperforms the traditional Uniform Linear array one in both estimation methods.
Small antennaarrays are advantageous for adhoc networks. Typically antenna array geometry is designed using simplified objective measures to make analysis tractable or maximize search efficiency. This paper investiga...
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ISBN:
(纸本)9781479923588
Small antennaarrays are advantageous for adhoc networks. Typically antenna array geometry is designed using simplified objective measures to make analysis tractable or maximize search efficiency. This paper investigates array design using fitness functions more tightly related to network performance. Particle swarm optimization (PSO) is used to design planar antennaarrays with minimum mean-square error or noise-to-signal ratio. Fitness functions are averaged across look angle to include effects of random signal and interference directions, resulting in a better measure of performance in real-world conditions. We found that irregular "T" or "diamond" geometries can outperform more common arrays such as Y or square arrays.
Small antennaarrays are advantageous for adhoc networks. Typically antenna array geometry is designed using simplified objective measures to make analysis tractable or maximize search efficiency. This paper investiga...
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ISBN:
(纸本)9781479923601
Small antennaarrays are advantageous for adhoc networks. Typically antenna array geometry is designed using simplified objective measures to make analysis tractable or maximize search efficiency. This paper investigates array design using fitness functions more tightly related to network performance. Particle swarm optimization (PSO) is used to design planar antennaarrays with minimum mean-square error or noise-to-signal ratio. Fitness functions are averaged across look angle to include effects of random signal and interference directions, resulting in a better measure of performance in real-world conditions. We found that irregular "T" or "diamond" geometries can outperform more common arrays such as Y or square arrays.
The next generation radio telescopes such as the Square Kilometer array (SKA) are expected to contain thousands of antennaarray elements operating over a broad frequency range where the signals from each antenna elem...
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The next generation radio telescopes such as the Square Kilometer array (SKA) are expected to contain thousands of antennaarray elements operating over a broad frequency range where the signals from each antenna element are combined and processed simultaneously providing high sensitivity with multiple beams providing a wide field of view. One crucial design aspect influencing both the performance and the cost of such systems is the arraygeometry. Due to the large bandwidth and number of broadband antenna elements, the optimization of such array system is difficult to achieve with the current arraygeometry optimization techniques which rely mainly on genetic algorithms and pattern search techniques. This paper provides a study of the effects of arraygeometry on the performance broadband array system. In addition, it provides a method where the arraygeometry can be more easily optimized for different applications. This is demonstrated for optimizing a typical SKA station in the frequency band between (70-450 MHz).
Due to relatively simple implementation, Uniform Linear array (ULA) is a popular geometry for array signal processing. Despite this advantage, it does not have a uniform performance in all directions and Angle of Arri...
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Due to relatively simple implementation, Uniform Linear array (ULA) is a popular geometry for array signal processing. Despite this advantage, it does not have a uniform performance in all directions and Angle of Arrival (AOA) estimation performance degrades considerably in the angles close to endfire. In this article, a new configuration is proposed which can solve this problem. Proposed array (PA) configuration adds two elements to the ULA in top and bottom of the array axis. By extending signal model of the ULA to the new proposed ULA-based array, AOA estimation performance has been compared in terms of angular accuracy and resolution threshold through two well-known AOA estimation algorithms, MUSIC and MVDR. In both algorithms, Root Mean Square Error (RMSE) of the detected angles descends as the input Signal to Noise Ratio (SNR) increases. Simulation results show that the proposed arraygeometry introduces uniform accurate performance and higher resolution in middle angles as well as border ones. The PA also presents less RMSE than the ULA in endfire directions. Therefore, the proposed array offers better performance for the border angles with almost the same array size and simplicity in both MUSIC and MVDR algorithms with respect to the conventional ULA. In addition, AOA estimation performance of the PA geometry is compared with two well-known 2D-array geometries: L-shape and V-shape, and acceptable results are obtained with equivalent or lower complexity.
In this paper, a new class of antenna array geometry is introduced. It is a threedimensional uniform rectangular array (3D-URA) made by four patch antennas. The array takes the advantages of high directivity and diver...
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ISBN:
(纸本)9781424449682
In this paper, a new class of antenna array geometry is introduced. It is a threedimensional uniform rectangular array (3D-URA) made by four patch antennas. The array takes the advantages of high directivity and diversity. Both calculated and experimental results are presented.
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