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adaptive array antenna for W-CDMA systems

FUJITSU SCIENTIFIC & TECHNICAL JOURNAL 2002年第2期38卷 192-200页

作者： Yasui, Y Kobayakawa, S Nakamura, T Fujitsu Labs Ltd Kawasaki Kanagawa 211 Japan

The adaptive array antenna (AAA) is one of the advanced techniques that will be implemented in the IMT-2000 mobile telecommunications systems to achieve a high system capacity. This paper describes an integrated AAA system for W-CDMA that consists of both uplink and downlink beam formers. We developed three functions for the AAA: a digital beam former using the normalized least mean square (NLMS) algorithm, a two-dimensional path searcher that works at a lower reception level than the conventional one, and a calibrator that compensates for variations in the amplitude and phase of signals at antenna branches. We built an experimental test bed, conducted field trials, and evaluated characteristics of the AAA such as the compensation accuracy of the calibrator and the path search sensitivity of the path searcher. The experimental results showed that the AAA is effective enough to improve system capacity.

关键词： .variations reception Interference downlink mean square uplink number of users calibrator NLMS adaptive array antenna antenna for CDMA array antenna AAA digital beam path searcher antenna branches

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adaptive array antenna using array antennas as element antennas

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IEICE TRANSACTIONS ON COMMUNICATIONS 2002年第10期E85B卷 1921-1926页

作者： Yamasuge, H Kohno, R Yokohama Natl Univ Fac Engn Yokohama Kanagawa 2408501 Japan

An adaptive array antenna should be applied for suppression of CCI in the spatial domain. However, the adaptive array antenna has some problems as follows. Because the adaptive array antenna takes a long time to converge to the optimum antenna weights, it's hard to track in case of quick varying channel. On the other hand, processing burden increases with the number of elements in the array antenna. To solve these problems, we propose an adaptive array antenna using array antenna as element antennas, the so-called "Layered array antenna." At the 1st layer, sector area are defined. We can change the sector areas according to the DOA distribution, because the sector areas are defined by the antenna weights. At the 2nd layer, MMSE is performed. Interference that couldn't be suppressed at the 1st layer is suppressed at the 2nd layer. By the proposed system, we confirmed higher convergence speed while relieving processing complexity.

关键词： adaptive array antenna smart antennas LMS algorithm adaptive sectored antennas

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adaptive array antenna BASED ON SPATIAL SPECTRAL ESTIMATION USING MAXIMUM-ENTROPY METHOD

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IEICE TRANSACTIONS ON COMMUNICATIONS 1994年第5期E77B卷 624-633页

作者： NAGATSUKA, M ISHII, N KOHNO, R IMAI, H UNIV TOKYO INST IND SCI TOKYO 113 JAPAN

An adaptive array antenna can be considered as a useful tool of combating with fading in mobile communications. We can directly obtain the optimal weight coefficients without updating in temporal sampling, if the arrival angles and signal-to-noise ratio (SNR) of the desired and the undesired signals can be accurately estimated. The Maximum Entropy Method (MEM) can estimate the arrival angles, and the SNR from spatially sampled signals by an array antenna more precisely than the Discrete Fourier Transform (DFT). Therefore, this paper proposes and investigates an adaptive array antenna based on spatial spectral estimation using MEM. We call it MEM array. In order to reduce complexity for implementation, we also propose a modified algorithm using temporal updating as well. Furthermore, we propose a method of both improving estimation accuracy and reducing the number of antenna elements. In the method, the *** can be approximately estimated by using temporal sampling instead of spatial sampling. Computer simulations evaluate MEM array in comparison with DFT array and LMS array, and show improvement owing to its modified algorithm and performance of the improved method.

关键词： adaptive array antenna MAXIMUM ENTROPY METHOD SPATIAL SAMPLING TEMPORAL SAMPLING

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adaptive array antenna Control Methods on Delay Tolerant Networks for Road Surveillance Systems 10

Adaptive Array Antenna Control Methods on Delay Tolerant Net...

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10th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS)

作者： Uchida, Noriki Ito, Kenta Hirakawa, Go Shibata, Yoshitaka Fukuoka Inst Technol Dept Informat & Commun Enginnering Higashi Ku 3-30-1 Wajirohigashi Fukuoka 8110295 Japan Iwate Prefectural Univ Fac Software & Informat Sci 152-52 Sugo Takizawa Iwate 0200193 Japan Network Applicat Engn Labs LTD JPR Hakata Bldg1-4-4 Hakataekimae Fukuoka 8120011 Japan

ISBN: (纸本)9781509009848

The road conditions during the winter especially in mountain areas are one of the significant safety subjects for the residences and the tourists. However, there are still many places where the wireless networks such as 3G and LTE are hard to connect in the mountain areas, and it is also difficult to keep continuous data transmissions during the nodes are moving. Therefore, this paper proposes the Delay Tolerant Networks (DTN) with adaptive array antenna (AAA) Control systems for the V2V networks. In the proposed systems, the vehicles equip the AAA control systems with IEEE802.11a/b/g in the proposed system, and the radio direction is controlled by the pattern recognitions from camera images with Kalman filter algorithm. The prototype system and the experiments are introduced in the paper, and the results are discussed for the effectiveness of the proposed systems and the future studies.

关键词： Road Surveillance Sytem Delay Tolerant Networks adaptive array antenna

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Multistage interference canceller combined with adaptive array antenna for DS-CDMA system

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2003年第7期E86A卷 1603-1610页

作者： Yano, K Hirose, S Yoshida, S Kyoto Univ Grad Sch Informat Kyoto 6068501 Japan

In order to increase the capacity of a DS-CDMA system, several kinds of interference suppression techniques have been studied, such as multiple access interference (MAI) cancellers and adaptive array antennas. However, their performance tends to degrade in high traffic-load situations. To compensate for the degradation, a receiver cascading an adaptive array antenna and a multistage parallel interference canceller (PIC) is studied in this paper. This receiver first uses an adaptive array antenna to suppress interference signals spatially, and uses a multistage PIC to suppress in-beam interference effectively. The performance of the cascaded receiver is evaluated with two schemes for antenna weight generation by computer simulations assuming a Rayleigh-distributed L-path channel. When antenna weights are generated for each user by an LMS algorithm, the cascaded receiver has shown better performance at the cost of a large number of pilot symbols and symbol by symbol weight update. Its performance degradation is 2.8 dB at the BER of 10(-4) even when the number of users increases from one to 24. On the other hand, when antenna weights are generated for each path by a DMI algorithm, its performance is degraded due to the inaccurate weight generation which occurs when the SINR of the desired signal is small. This degradation can be mitigated by using all signals of the desired user received by all antenna patterns of desired user for RAKE combining when the difference among arrival angles of the paths of the desired user is small.

关键词： DS-CDMA adaptive array antenna multistage MAI canceller interference suppression

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MFOA-Integrated Modified Inverted F-Based adaptive array antenna for 2.4 GHz Band Applications

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INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING 2016年第9期26卷 784-795页

作者： Kawdungta, Supakit Phongcharoenpanich, Chuwong Rajamangala Univ Technol Lanna Fac Engn Chiang Mai 50300 Thailand King Mongkuts Inst Technol Ladkrabang Fac Engn Bangkok 10520 Thailand

This research has proposed a modified fruit fly optimization algorithm (MFOA)-integrated adaptive array antenna (AAA) for the 2.4-2.5 GHz WLAN system. The principal components of the array antenna system encompass four array elements, four band pass filters (BPF), four digital phase shifters, a four-way power combiner/splitter, a directional coupler, a radio frequency (RF) detector, and a microcontroller unit (MCU). In the realization of the adaptive antenna system, the modified inverted F antenna with a finite ground plane was first innovated and subsequently deployed as the element of the fourelement array antenna. In the study, simulations and experiments were carried out with the four-element AAAs of two configurations, i.e. the linear and planar array configurations. The simulation and experimental results revealed that the MFOA algorithmic scheme could determine the direction of the maximum arrival signal in an efficient and accurate manner and also was capable of manipulating the radiation pattern in the desired direction. In addition, the MFOA-integrated four-element AAA is of compact size (20 mm 3 35 mm 3 1.8 mm) and operable in the 2.31-2.55 GHz frequency band with omnidirectional radiation pattern and a gain of 1.6 dBi. (C) 2016 Wiley Periodicals, Inc.

关键词： adaptive array antenna beamforming fruit fly optimization inverted F antenna wireless communication WLAN system

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Simple null-steering OFDM adaptive array antenna for Doppler-shifted signal suppression

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2005年第1期54卷 91-99页

作者： Hara, S Hane, S Hara, Y Osaka Univ Dept Elect Informat Syst & Energy Engn Grad Sch Engn Osaka 5650871 Japan Tokyo Elect Power Co Ltd Tokyo 1008560 Japan Mitsubishi Elect Informat Technol Ctr Europe BV ITE F-35708 Rennes France

A new null-steering method to suppress Doppler-shifted signals is proposed for orthogonal frequency-division multiplexing adaptive array antenna. The proposed array antenna has a simple structure and can steer nulls for interfering signals even with small Doppler shifts by forcing virtual subcarrier outputs to be zero. A multistep recursive least-square algorithm is proposed to control the array weights and the bit-error rate and antenna pattern are evaluated by computer simulation.

关键词： adaptive array antenna Doppler shift null steering orthogonal frequency-division multiplexing (OFDM)

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Implementation of joint Pre-FFT adaptive array antenna and Post-FFT space diversity combining for mobile ISDB-T receiver

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IEICE TRANSACTIONS ON COMMUNICATIONS 2008年第1期E91B卷 127-138页

作者： Pham, Dang Hai Gao, Jing Tabata, Takanobu Asato, Hirokazu Wada, Tomohisha Univ Ryukyus Dept Informat Engn Fac Engn Okinawa 9030213 Japan Magna Desing Net Inc Naha 9010152 Japan Kojima Press Ind Co Ltd Aichi 4700207 Japan

In our application targeted here, four on-glass antenna elements are set in an automobile to improve the reception quality of mobile ISDB-T receiver. With regard to the directional characteristics of each antenna, we propose and implement a joint Pre-FFT adaptive array antenna and Post-FFT space diversity combining (AAA-SDC) scheme for mobile ISDB-T receiver. By applying a joint hardware and software approach, a flexible platform is realized in which several system configuration schemes can be supported;the receiver can be reconfigured on the fly. Simulation results show that the AAA-SDC scheme drastically improves the performance of mobile ISDB-T receiver, especially in the region of large Doppler shift. The experimental results from a field test also confirm that the proposed AAA-SDC scheme successfully achieves an outstanding reception rate up to 100% while moving at the speed of 80km/IL

关键词： adaptive array antenna space diversity combining OFDM ISDB-T FPGA DSP

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An adaptive array antenna based on the IQ-division bandpass sampling

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IEICE TRANSACTIONS ON COMMUNICATIONS 2003年第12期E86B卷 3483-3490页

作者： Sasaki, S Taniguchi, T Karasawa, Y Univ Electrocommun Dept Elect Engn Chofu Tokyo 1828585 Japan

In this paper, as an important technology for the software-defined radio, a novel scheme of adaptive array antenna utilizing bandpass sampling technique is proposed. For adaptive signal processing, it is necessary to convert the radio frequency signal received by the antenna that is given by real number into baseband region, i.e., complex number region. Then, the method for dividing the bandpass sampled signal to in-phase and quadrature components is analyzed. The sampling scheme is called the IQ-division bandpass sampling. An adaptive array antenna based on the IQ-division bandpass sampling is characterized by the signal processing at the bandpass sampled signal stage, namely, intermediate frequency stage, not baseband. Finally, we will confirm the validity of the proposed scheme through an experiment in a radio anechoic chamber.

关键词： IQ-division bandpass sampling adaptive array antenna software defined radio

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A simple configuration of adaptive array antenna for DS-CDMA systems

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IEICE TRANSACTIONS ON COMMUNICATIONS 2003年第3期E86B卷 1117-1124页

作者： Kihira, K Yonezawa, R Chiba, I Mitsubishi Electr Corp Informat Technol R&D Ctr Kamakura Kanagawa 2478501 Japan Mitsubishi Electr Corp Kamakura Works Kamakura Kanagawa 2478520 Japan

An adaptive array antenna for the suppression of high-power interference in direct-sequence code-division multiple access (DS-CDMA) systems is presented. Although DS-CDMA has sufficient flexibility to support a variety of services, from voice to moving-pictures, with high levels of quality, multiple access interference (MAI) is a problem. This is particularly so of the high-power interference which accompanies highspeed transmission in DS-CDMA. While the application of adaptive array antennas is an effective way of improving signal-to-interference-plus-noise ratio (SINR), problems with this approach include large levels of power consumption and the high costs of hardware and of implementing the antennas. Therefore, our main purpose is to realize a simple configuration for an adaptive array system. In order to reduce the required amounts of processing, a common beam provides suppression of high-power interference for the low-bit-rate users;, this makes per-user preparation of weights unnecessary. This approach also reduces the consumption of power by the system. Interference is cancelled by minimization of the array output power (i.e., the application of a power inversion algorithm) before despreading. The approach also allows us to improve the implementation of the antenna elements by using small auxiliary antennas. The basic performance of the system is confirmed through numerical calculation and computer simulation. Furthermore, a real-time processing unit has been developed and the effectiveness of the approach is confirmed by an experiment in a radio-anechoic chamber.

关键词： adaptive array antenna DS-CDMA power inversion algorithm

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