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An adaptive antenna array for single carrier modulation with cyclic prefix

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2005年第9期88卷 38-48页

作者： Hayashi, K Kojima, T Sakai, H Kyoto Univ Grad Sch Informat Dept Syst Sci Kyoto 6068501 Japan

In this paper, a method for weight control of an adaptive array is proposed for a system using a cyclic prefix in single carrier wireless communications (SC-CP). In the SC-CP system, the delayed wave within the guard interval (GI) can be equalized by discrete frequency domain equalization. Therefore, it is to be expected that the characteristics can be improved with respect to the received signal power by reception of several arriving waves within the GI. On the other hand, reception of several arriving waves leads to generation of zero points in the frequency response so that noise enhancement may be a problem for a discrete frequency domain equalizer with a zero forcing (ZF) reference. Also caused in the SC-CP system are the intersymbol interference (ISI) and interblock interference (IBI) due to the delayed wave exceeding the GI length. In this paper, a weight control method is proposed that simultaneously realizes enhanced received signal power by reception of several arriving waves and avoidance of noise enhancement due to ZF reference equalizer. At the same time, the weight control method to suppress delayed waves outside the GI is theoretically derived and its characteristics are evaluated by a computer simulation. (c) 2005 Wiley Periodicals, Inc.

关键词： cyclic prefix single carrier adaptive array noise enhancement

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A Novel LMS Beamformer for adaptive Antenna array

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Procedia Computer Science 2017年 115卷 94-100页

作者： Veerendra Md.Bakhar Research Scholar Department of E&CE Visvesvaraya Technological University Belagavi Department of E&CE Guru Nanak Dev Engineering College Bidar - 585403 Karnataka India

Least Mean Square (LMS) beamforming algorithm is one of the most popular method in array signal processing due to its low complexity. The main downside of this method is low convergence rate which limits its application in many wireless communications. In this paper, we proposed a novel LMS algorithm which produces satisfactory performance within 6 iterations. We used novel structure which consists of two LMS modules, one converse speediness module and speediness module. The experimental results show that novel LMS algorithm is superior in convergence rate and has about 92.5% of improvement over classical LMS algorithm.

关键词： adaptive array beam forming LMS NLMS MSE

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Beamspace adaptive array antenna for broadband signals

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Electronics and Communications in Japan (Part I: Communications) 1998年第10期80卷

作者： Takashi Sekiguchi Ryu Miura Yoshio Karasawa ATR Optical and Radio Communications Research Laboratories Kyoto Japan 619-02

In this paper, we propose a beamspace adaptive array antenna for broadband signals with a wide fractional bandwidth. The proposed beamspace adaptive array antenna has a multiple digital beamforming network that preserves spectral components of input broadband signals by using tapped-delay-line circuits. Coefficients of the tapped-delay-line circuits are determined such that each broadband digital beamforming network has the same phase characteristics, and the beam pattern including sidelobe and null characteristics is virtually frequency independent. A few adaptive weights, which are linear combination coefficients of the selected broadband beams, follow a beam selector. The number of adaptive weights for the proposed adaptive array is considerably less than that of an element space structure with tapped-delay-line circuits. We demonstrate by computer simulation that interference suppression by the proposed beamspace adaptive array is as good as that of an element space adaptive array and that it has much faster convergence. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(10): 38–48, 1997

关键词： adaptive array digital beamforming antenna adaptive signal processing

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Performance evaluation of packet reservation multiple access with an adaptive array

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Electronics and Communications in Japan (Part I: Communications) 1999年第3期83卷

作者： Tsugunao Kobayashi Iwao Sasase Department of Electrical Engineering Keio University Yokohama Japan 223-8522

For local wireless communications, the packet reservation multiple access (PRMA) protocol, which combines random access with time division access, is known as an efficient access method to use silence periods of voice traffic. However, the performance of PRMA at the base station is degraded under heavy load conditions where many mobile stations transmit packets at the same time, because of the contention mechanism of random access. Also, for integrated transmission of voice and data, the performance of the voice terminal is degraded due to the data traffic. In this paper, we propose the use of the adaptive array antenna with PRMA protocol to improve the performance. In the proposed model, the adaptive array can acquire a packet by pointing the peak antenna pattern toward that packet even when a collision occurs. First, we evaluate the throughput and the packet dropping probability for voice-only traffic by theoretical Markov analysis and computer simulation, and show that the proposed model attains higher throughput and lower packet dropping probability than the conventional PRMA when the traffic load is high. Next, we evaluate the throughput and the packet dropping probability for integration of voice and data traffic by computer simulation, and show that the proposed model reduces the performance degradation of the voice terminal due to the addition of data traffic, compared to the conventional PRMA. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 83(3): 36–48, 2000

关键词： packet reservation multiple access adaptive array throughput packet dropping probability

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Throughput performance of slotted nonpersistent CSMA with an adaptive array

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Electronics and Communications in Japan (Part I: Communications) 1998年第9期80卷

作者： Akira Sugihara Kei Enomoto Iwao Sasase Dept. of Electrical Engineering Keio University 3-14-1 Hiyoshi Kohoku Yokohama Japan 223

In conventional slotted nonpersistent CSMA, a packet is generated during a slot, and the terminal senses the channel at the beginning of the next slot. It is known that slotted CSMA has better throughput performance than unslotted CSMA. However, because of the propagation delay, if more than two packets are generated during the same slot, later packets might sense the channel as idle, and they will cause a conflict. Furthermore, when the CSMA modes are used in practical radio communication systems, the hidden-terminal problem should be considered. We propose a slotted nonpersistent CSMA with an adaptive array at the receiver to improve throughput performance. In our proposed model, in order for an adaptive array to distinguish packets during the same time slot and acquire the first arriving packet, the starting times of packet transmission from all terminals are randomized over the interval which is the difference between the slot width and the packet width. First, we analyze the performance of the throughput and the average number of transmissions and schedulings. We also evaluate the performance by means of computer simulation in order to consider the hidden-terminal problem in the CSMA mode. It is found that the theoretical results of the proposed model agree well with the computer simulated results, and the proposed model attains higher throughput and smaller average numbers of transmissions and schedulings than the conventional slotted nonpersistent CSMA. It is also shown that the performance of the proposed model with an adaptive array due to hidden-terminal degradation is smaller compared to the conventional CSMA. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(9): 34–43, 1997

关键词： Slotted nonpersistent CSMA adaptive array throughput average number of transmissions scheduling hidden terminal

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Robust response control for adaptive beamformers against arbitrary array imperfections

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SIGNAL PROCESSING 2008年第9期88卷 2234-2245页

作者： Yu, Zhu Liang Ser, Wee Er, Meng Hwa Gu, Zhenghui Nanyang Technol Univ Ctr Signal Proc Singapore 639798 Singapore S China Univ Technol Sch Automat Sci & Engn Guangzhou Peoples R China Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore Inst InfoComm Res Singapore 119613 Singapore

The recently proposed robust adaptive beamformers, which utilize the autocorrelation sequence of array weight, were formulated as linear optimization problems. With the constraints on magnitude response (CMRs), we are able to control the robust response region of these adaptive beamformers with specified beamwidth and response ripple. Hence, they are robust against large steering direction errors. In practice, many array imperfections may cause the violation of the CMRs, which results in target signal cancellation. In this paper, a novel adaptive beamformer is proposed with new robust CMRs that are derived based on the worst-case optimization. With the robust CMRs, the proposed beamformer is formulated as a linear programming problem with linear and second-order conic constraints. It possesses superior robustness against arbitrary array imperfections and high performance on signal-to-interference-plus-noise ratio (SINR) enhancement. Simple implementation, flexible performance control as well as high SINR enhancement support the practicability of the proposed method. (c) 2008 Elsevier B.V. All rights reserved.

关键词： robust adaptive beamforming adaptive array constraints on magnitude response spectral factorization linear programming worst-case optimization second-order cone optimization

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Experimental investigations of a new adaptive dual-antenna array for handset applications

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2003年第6期52卷 1417-1423页

作者： Denidni, TA McNeil, D Delisle, GY Univ Quebec EMT INRS Montreal PQ H5A 1K6 Canada Gelus Mobil Inc Montreal PQ H4S 2CS Canada Univ Ottawa Fac Engn Sch Informat Technol & Engn Ottawa ON K1N 6N5 Canada

This paper presents the design and implementation of a new adaptive dual-antenna array for mitigation of both interference and multipath effects in digital mobile communications at the handset level. This proposed system employs a nonlinear adaptive algorithm in the front end of the receiver to enhance the transmission quality in confined areas. The enhancement is blind since no priori knowledge of spatial signatures or training sequences is required. Furthermore, to obtain a compact antenna array system, a miniaturized shorting postmicrostrip antenna that operates in the 1.9 GHz PCS band is used as a radiating element. Using this microstrip antenna, a new experimental adaptive dual-antenna array prototype was designed and implemented. To examine the expected performance of this approach, experimental measurements were carried out and the measured performances indicate that gain improvement of 7 dB can be achieved by using this approach.

关键词： adaptive array fading channels handset antenna interference

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Performance Analysis of Anti-Interference Wireless Packet Networks for LEO Micro-Satellite with adaptive Nulling Antenna array

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The Journal of China Universities of Posts and Telecommunications 2006年第2期13卷 10-14页

作者： LIU Hai-tao HAN Fang-jing WAN Jian-wei School DSP Group of National University of Defense Technology Changsha 410073 P.R. China

Information integrity is key to successful operations in intricacy environments in the future, especially when strong interferences exist. This paper presents the design of a novel wireless packet network receiver system for Low Earth Orbit （LEO） micro-satellites with adaptive nulling antenna arrays. It uses three types of interference suppression in cascade： namely spread spectrum, adaptive array nulling, and transform domain filtering. This paper proposes a pilot channel-aided method in order to make full advantage of this arrangement, and analyzes its throughput and delay performance using the Markov chain model. Our results show that this method can achieve excellent delay and throughput performance： When the number of array antenna is 8, its throughput increase relative to the standard Slot-ALOHA protocol is 125 96.

关键词： LEO adaptive array ALOHA packet radio networks

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GSC-based adaptive beamforming with multiple-beam constraints under random array position errors

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SIGNAL PROCESSING 2004年第2期84卷 341-350页

作者： Lee, JH Cho, CL Natl Taiwan Univ Dept Elect Engn Taipei 106 Taiwan

This paper deals with the problem of adaptive beamforming under random array position errors to provide multiple-beam constraints and suppress jammers simultaneously. Using a steering matrix with each column vector corresponding to the steering vector of a selective beam and a constraint vector with each entry equal to the gain of a selective beam, we construct the quiescent weight vector and the blocking matrix required by a generalized sidelobe canceller (GSC) to achieve a GSC-based adaptive array beamformer with multiple-beam constraints. For coping with the performance degradation due to random perturbations in array sensor positions, an iterative matrix reconstruction scheme in conjunction with derivative constraints is presented to alleviate the effect of random position errors. Simulation results show the effectiveness of the proposed technique. (C) 2003 Elsevier B.V. All rights reserved.

关键词： generalized sidelobe canceller adaptive array multiple beams random position error

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Performance evaluation of decision feedback adaptive arrays based on interarray correlation-neglecting algorithm

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 2003年第6期52卷 1424-1434页

作者： Denno, S ATR Adapt Commun Res Labs Kyoto 6190288 Japan

This paper presents the performance of a decision feedback adaptive array based on the interarray correlation-neglecting (ICN) algorithm that is suitable for high-speed mobile-communication systems. Although the ICN algorithm is regarded as a means of complexity reduction from recursive least-square (RLS) algorithm, we present that the ICN algorithm has a superior initial acquisition performance close to RLS algorithm, theoretically. The requirements for stable convergence are analytically revealed. Moreover, the performance is confirmed by Monte Carlo simulation. Besides, since the decision feedback adaptive array based on the ICN algorithm can be easily implemented with parallel processing, this array can reduce run-time cycles needed for one symbol. Therefore, this array can be applied to high-speed radio communication systems. In addition to this, the low operational complexity of this array makes it easy to apply this for high-speed mobile-communication systems where low complexity is basically required.

关键词： adaptive array complexity reduction decision feedback equalization fast acquisition high-speed transmission

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