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adaptive array-PROCESSING USING THE DAVIES BEAMFORMER

IEE PROCEEDINGS-H MICROWAVES ANTENNAS AND PROPAGATION 1986年第6期133卷 467-473页

作者： KO, CC Department of Electrical Engineering National University of Singapore Singapore Singapore

The paper presents and analyses a simple and fast adaptive array based on the Davies null-steering beamformer [1]. The use of perturbation algorithms on this beamformer is investigated. The convergence time constants and misadjustment are derived. It is shown that, if the feedback factors for these algorithms are appropriately normalised, the time constants can be roughly equalised, resulting in fast convergence behaviour.

关键词： misadjustment Antenna theory adaptive array antenna radiation patterns feedback factors antenna phased arrays convergence time constants null-steering beamformer Davies beamformer Antenna arrays perturbation algorithms antenna theory

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adaptive array for reducing high-power CCI on asynchronous TDD systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 2001年第7期E84B卷 1727-1734页

作者： Nishimori, K Cho, K Takatori, Y Hori, T NTT Network Innovat Labs Yokosuka Kanagawa 2390847 Japan

This paper proposes a novel adaptive array configuration that reduces high-power co-channel interference (CCI) by utilizing the difference in arrival times between CCI and the desired signal in asynchronous TDD systems. The proposed adaptive array extracts only the CCI and employs pre-null steering for only the CCI by utilizing the fact that only the CCI arrives during the guard time in asynchronous TDD systems. Since the proposed adaptive array enables us to apply the Minimum Mean Square Error (MMSE) algorithm through synchronization with the desired signal using the output signal obtained by pre-null steering, high quality transmission can be achieved even in the presence of high-power CCI. Moreover, based on measurements using a fading simulator and field data, an adaptive array testbed exemplifying the proposed configuration is presented to show the reduction in the high-power CCI.

关键词： adaptive array asynchronous TDD systems power inversion MMSE guard time

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adaptive array employing eigenvector beam of maximum eigenvalue and fractionally-spaced TDL with real tap

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IEICE TRANSACTIONS ON COMMUNICATIONS 2000年第8期E83B卷 1678-1687页

作者： Takatori, Y Cho, K Nishimori, K Hori, T NTT Network Innovat Labs Yokosuka Kanagawa 2390847 Japan

This paper proposes a new digital beamforming adaptive array antenna (DBFAAA) that is effective in severe multipath environments in which timing and carrier synchronization circuits cannot function ideally resulting in the DBFAAA losing control. The proposed DBFAAA has two stages. In the first, the DBFAAA captures the desired signal and establishes synchronization. In the second, the DBFAAA optimizes the beam pattern of the signal. The proposed configuration employs an eigenvector beam of the maximum eigenvalue in the first stage beam-forming. in addition, a fractionally-spaced-tapped-delay-line (FS-TDL) with real tap weights, which is placed after the beam-former, is applied to achieve timing synchronization. The behavior of the proposed DBFAAA for asynchronous sampling data is investigated and the results indicate that the proposed configuration enables asynchronous sampling at the A/D converter. A prototype of the proposed DBFAAA achieving 38-Mbps real-time data communication is introduced and the transmission performance is shown.

关键词： adaptive array digital beamforming eigenvector beam high-speed wireless access fractionally-spaced-tapped-delay-line

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adaptive array utilising improved spatial averaging technique

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ELECTRONICS LETTERS 2000年第5期36卷 471-472页

作者： Serebryakov, GV Inst Appl Math & Cybernet Nizhnii Novgorod 603005 Russia

A further development of spatial smoothing is proposed based on the spatial averaging of the covariance matrices obtained by the subarrays. The proposed averaging technique uses spatial smoothing with some weighting, ... 详细信息

关键词： interference suppression adaptive antenna arrays spatial averaging technique Electromagnetic compatibility and interference array signal processing coherent interference suppression spatial smoothing adaptive array Algebra Signal processing and detection weighting subarrays Antenna arrays covariance matrices

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Effects of Power Inversion Spatial Only adaptive array on GNSS Receiver Measurements

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Tsinghua Science and Technology 2018年第2期23卷 172-183页

作者： Hailong Xu Xiaowei Cui Mingquan Lu Department of Electronic Engineering Tsinghua University Beijing 100084 China.

The Spatial Only Processing Power Inversion(SOP-PI) algorithm is frequently used in Global Navigation Satellite System(GNSS) adaptive array receivers for interference mitigation because of its simplicity of implementation. This study investigates the effects of SOP-PI on receiver measurements for high-precision applications. Mathematical deductions show that if an array with a centro-symmetrical geometry is used, ideally,SOP-PI is naturally bias-free; however, this no longer stands when non-ideal factors, including array perturbations and finite-sample effect, are added. Simulations are performed herein to investigate how exactly the array perturbations affect the carrier phase biases, while diagonal loading and forward-backward averaging are proposed to counter the finite-sample effect. In conclusion, whether SOP-PI with a centro-symmetrical array geometry will satisfy the high precision demands mainly depends on the array perturbation degree of the element amplitude and the phase center.

关键词： Global Navigation Satellite System(GNSS) receiver adaptive array high-precision application power inversion measurement bias array perturbation diagonal loading forward-backward averaging

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THE DIFFERENTIAL CMA adaptive array ANTENNA USING AN EIGEN-BEAMSPACE SYSTEM

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IEICE TRANSACTIONS ON COMMUNICATIONS 1995年第11期E78B卷 1480-1488页

作者： NISHIMORI, K KIKUMA, N INAGAKI, N Nagoya Inst of Technology Nagoya-shi Japan

This paper addresses approaches to enhancement of performance of the CMA (Constant Modulus Algorithm) adaptive array antenna in multipath environments that characterize the mobile radio communications. The cost function of the CMA reveals that it has an AGC (Automatic Gain Control) procedure of holding the array output voltage at a constant value. Therefore, if the output voltage by the initial weights is different from the object value, then the CMA may suffer from slow convergence because suppression of the multipath waves is delayed by the AGC behavior. Our objective is to improve the convergence characteristics by adopting the differential CMA for the adaptive array algorithm. First, the basic performance of the differential CMA is clarified via computer simulation. Next, the differential CMA is incorporated into the eigen-beamspace system in which the eigenvectors of the correlation matrix of array inputs are used in the BFN (Beam Forming Network). This BFN creates the optimum orthogonal multibeams for radio environments and works helpfully as a preprocessor of the differential CMA. The computer simulation results have demonstrated that the differential CMA with the eigen-beamspace system has much better convergence characteristics than the conventional CMA with the element space system. Furthermore, a modified algorithm is introduced which gives the stable array output voltages after convergence, and it is confirmed that the algorithm can carry out more successful adaptation even if the radio environments are changed abruptly.

关键词： adaptive array DIFFERENTIAL CMA EIGEN-BEAMSPACE SYSTEM MOBILE COMMUNICATION MARQUARDT METHOD STEEPEST DESCENT METHOD

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Novel DOA estimation method for HA adaptive array applicable to TDMA mobile satellite communication systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 1998年第7期E81B卷 1535-1541页

作者： Kamiya, Y Nomoto, S Kobayashi, H KDD R&D Labs Radio Commun Lab Kamifukuoka Saitama 3568502 Japan Mie Univ Tsu Mie 5148507 Japan

The applications of adaptive arrays based on the digital beam forming technique are receiving wide attention. However, the adaptive control algorithm of the array antennas under TDMA systems is not well considered even though it requires particular consideration due to its intermittent bursts. In this paper, first, we propose a novel DOA (Direction of Arrival) estimation method which is suitable for TDMA bursts. Second, the HA (Howells-Applebaum) adaptive array based on the proposed DOA estimation method will be constructed for the terminals in the mobile communication systems using non-geostationary satellites. Then the performance of the DOA estimation method and the HA adaptive array will be examined through computer simulations and experiments.

关键词： adaptive array Howells-Applebaum TDMA DOA estimation digital beamforming

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A CMA adaptive array antenna system with a single receiver using time-division multiplexing

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IEICE TRANSACTIONS ON COMMUNICATIONS 2001年第6期E84B卷 1637-1646页

作者： Moriyama, E Kamio, Y Hamaguchi, K Furukawa, H Independent Adm Inst Commun Res Lab Yokosuka Kanagawa 2390847 Japan Natl Police Agcy Tokyo 1008974 Japan

We describe a simplified receiver structure having several receiving antennas (i.e., an adaptive array antenna system) and using time-division-multiplexing (TDM) signal processing. Three simplified receiver structures were investigated for use in the antenna system. To confirm the feasibility of using a TDM receiver, both a TDM receiver and a conventional adaptive array receiver were constructed for testing. In our proposed system, several repetitions of the constant modulus algorithm (CMA) are used to reduce co-channel interference (CCI). The frame format used for both receivers was the same as that of the personal handy phone system in Japan. The laboratory testing was done using a fading simulator to enable measurement of the bit error rate. The results are very promising and show the feasibility of the TDM receiver.

关键词： constant nodulus algorithm adaptive array cochannel interference time-division multiplexing

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Novel spatiotemporal equalization based on cascaded connection of multibeam adaptive array and multi-input MLSE

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2005年第6期4卷 2716-2725页

作者： Tanabe, Y Hanaki, A Ohgane, T Ogawa, Y Toshiba Co Ltd Kawasaki Kanagawa 2128582 Japan NTT Corp DoMoCo Inc Yokosuka Kanagawa 2398536 Japan Hokkaido Univ Grad Sch Informat Sci & Technol Sapporo Hokkaido 0600814 Japan

This paper proposes a novel spatiotemporal equalizer using a cascaded connection of multibeam adaptive array and multi-input maximum likelihood sequence estimation (MLSE) based on single-user detection. The computational load for the proposed method is much lower than that of the optimal method, and computer simulations revealed that its bit-error-rate (BER) performance is identical to that of the optimal method. Theoretical analysis also supports equivalency between these methods.

关键词： adaptive array eigenanalysis interference reduction maximum likelihood sequence estimation spatiotemporal equalizer time-dispersive channel

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Design and Experiment of Reduced-Dimension adaptive array Based on FIR Filters

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2021年第2期20卷 204-208页

作者： Yang, Peng Zhou, Wei Univ Elect Sci & Technol China Sch Elect Sci & Engn Chengdu 611731 Peoples R China

The reduced-dimension adaptive array is interesting because it is a promising method to lower the computational complexity of an adaptive beamformer. In this letter, we present a simple method for reduced-dimension adaptive antenna design based on the spatial filters. By using a set of finite impulse response filters to construct a transformation matrix with lower rank, the receiving data in element space are transformed to beamspace. Simulation results show that this method is effective in reducing the adaptive dimension of the array while keeping the performance as its element space counterpart. A four-element microstrip array is fabricated for experiment and a direct-sampling-data-based method is proposed for calibration.

关键词： Interference Signal to noise ratio Butler matrices Time-domain analysis Finite impulse response filters adaptive arrays arrays adaptive array finite impulse response (FIR) filter reduced dimension

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