• Title/Summary/Keyword: Beamforming System

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Adaptive beamforming for a PF-OFDM system using LMS algorithm (LMS기반 PF-OFDM에서의 적응 빔포밍 설계)

  • Yoo, Kyung-Rul;Oh, Jun-Suk
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.3
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    • pp.119-123
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    • 2006
  • The orthogonal frequency-division multiplexing (OFDM) technique is well known to be robust against the frequency-selective fading in wireless channels. It is due to the exploitation of a guard interval that is inserted at beginning of each OFDM symbol. Based on the conventional OFDM and a polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique, we developed an adaptive beamforming algorithm for antenna arrays. The proposed algorithm would lead to an efficient use of channel, since it is possible to eliminate a guard interval and also easily suppress interchannel interference at the same time. In this paper, a series of computer simulations have been provided to show the performance of the proposed system.

Enhanced Adaptive Beamforming and Null Steering Algorithms in Cognitive Radio System

  • Zhuang, Zhili;Sohn, Sung-Hwan;Kim, Jae-Moung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.11A
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    • pp.822-830
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    • 2009
  • The spectrum efficiency of mobile communication networks can be improved dramatically adopting multiple antennas technologies. In order to guarantee the licensed rights of primary user (PU), the cognitive radio system should perform in a relatively low interference manner when it gets access to the spectrum of licensed networks. In this paper, we explore a uniformly distributed circular antenna array to implement beamforming algorithm that is accomplished by optimization method at the base station of cognitive radio networks, and therefore we can suppress the interference to PU by steering quite low transmission power toward PU and constructing a narrow beam toward cognitive user (CU). By reducing the constraint number of the optimization problem, we also propose a null steering algorithm that steers rather low radiation power toward PU, while the other areas in the same cell are covered by radiation power except the local area around PU. It is pursued to reduce the computation load and enlarge the capacity of cognitive radio networks extremely. The simulation results demonstrate that the proposed algorithms process superior performance.

Implementation of Smart Antenna Beamforming Module Utilizing Signal Processing Chip in CDMA2000 (신호처리 칩을 이용한 CDMA2000 스마트 안테나 빔형성 모듈 구현)

  • Ahn, Sung-Soo
    • Journal of Satellite, Information and Communications
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    • v.5 no.1
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    • pp.38-42
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    • 2010
  • This paper shows that beamfoming module deign to adapt smart antenna system in CDMA2000 environments. The designed beamfroming module has been implemented on a general-purpose DSP as a test-bed to confirm the superior performances based on real-time processing. From the various simulation result, it is confirm that beamforming module is provide a superior beampattern in smart antenna system.

Remote speech recognition preprocessing system for intelligent robot in noisy environment (지능로봇에 적합한 잡음 환경에서의 원거리 음성인식 전처리 시스템)

  • Gwon, Se-Do;Jeong, Hong
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.365-366
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    • 2006
  • This paper describes a pre-processing methodology which can apply to remote speech recognition system of service robot in noisy environment. By combining beamforming and blind source separation, we can overcome the weakness of beamforming (reverberation) and blind source separation (distributed noise, permutation ambiguity). As this method is designed to be implemented with hardware, we can achieve real-time execution with FPGA by using systolic array architecture.

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Performance of a Coherent QPSK System with an Adaptive Antenna Array at Base Station

  • Le Minh-Tuan;Pham Van-Su;Yoon Gi-Wan
    • Journal of information and communication convergence engineering
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    • v.4 no.1
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    • pp.10-12
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    • 2006
  • In this paper, we present a method to evaluate the BER performance of a coherent QPSK system using an adaptive array to eliminate CCI and demonstrate closed-form expressions for obtaining exact BER of the desired user for the case in which the time delays of all users are equal. The theoretical results are verified by computer simulation under the assumption that Least Mean Square beamforming algorithm is employed.

A 60GHz Wireless Cooperative Communication System Based on Switching Beamforming

  • Shi, Wei;Wang, Jingjing;Liu, Yun;Niu, Qiuna;Zhang, Hao;Wu, Chunlei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.10 no.4
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    • pp.1590-1610
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    • 2016
  • The challenge of penetrating obstacles along with impact from weak multipath effects makes 60GHz signal very difficult to be transmitted in non-line of sight (NLOS) channel. So 60GHz system is vulnerable to obstructions and thus likely results in link interruption. While the application of cooperative technology to solve link blockage problemin 60GHz system should consider the characteristic of directional transmission for 60GHz signal. Therefore in this paper a system is proposed to solve the link blockage problem in 60GHz NLOS communication environment based on the concept of cooperation and also the beamforming technology, which is the basis of directional transmission for 60GHz communication system. The process of anti-blockage solution with cooperative communication is presented in detail, and the fast switching and recovery schemes are well designed. The theoretical values of symbol error rate (SER) using decode and forward (DF) cooperation and amplify and forward (AF) cooperation are presented respectively when the common channel interference exists. Simulation results demonstrate that the performance based on DF cooperation is better than the performance based on AF cooperation when directional transmission is used.

Blind Turbo Equalization System with Beamforming (빔포밍이 적용된 블라인드 터보 등화기)

  • Kim, Yongguk;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38A no.10
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    • pp.850-857
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    • 2013
  • Turbo equalizer system is a method which can improve performance through a combination of the equalizer and decoder. The turbo equalizer has been mainly used a MAP equalizer. However, this turbo equalizer has a disadvantage that has a high computational complexity. To overcome the disadvantage and to improve efficiency of bandwidth, blind turbo equalization system is proposed. blind turbo equalization system has low equalization performance than conventional turbo equalization system. To circumvent this problem, we adapt the beamforming method based on the MUSIC algorithm. we confirmed that the proposed method improves the equalization performance.

Adaptive Transmission & Receiving Technology Considering Spatial Channel Correlation in Multiple Antenna Systems (공간 채널 상관도에 따른 다중 안테나 시스템의 적응 송.수신 기법)

  • Park Sung-Ho;Kim Kyoo-Hyun;Chang Kyung-Hi
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.9A
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    • pp.844-855
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    • 2006
  • The communication system using multiple antennas improves link reliability or system capacity using tx & rx diversity, spatial multiplexing, and beamforming technique with services and characteristics of channel environment. This system is sensitive to spatial channel environment. In case of diversity, the lower correlation among links as a LoS environment, the better performance is acquired. In practical channel environment, However, there is high correlation, and there is high performance difference between ideal case and practical case. On the contrary, in case of beamforming, the higher correlation among links, the better performance is acquired. If we use the spatial adaptive transmission technique with spatial channel characteristics, we can get the system that maintains minimum link reliability and guarantees the overall system performance. In this paper, we propose the adaptive transmission and reception technique which use diversity or beamforming technique with channel characteristics.

Blind Beamforming Equalization System Based on MUSIC Algorithm (MUSIC 알고리즘 기반 블라인드 빔포밍 등화 시스템)

  • Kim, Yongguk;Lee, Seung Hwan;Shin, Dong Jin;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.1
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    • pp.64-72
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    • 2013
  • Blind equalization is a technique that equalizes the received signals without the training sequence. Because of the absence of training sequence, we can increase the bandwidth efficiency due to the blind equalization system. And we must use the blind equalization for removing the ISI in mobile satellite communication receiver. ISI occurs due to mobility of users in mobile satellite communications. Blind equalization is suitable for the mobile satellite communication channels. In this blind equalization, it's very important to improve BER performance to apply the mobile satellite communication system. In this paper, we propose the blind beamforming equalization system using the beamforming, MUSIC algorithm and coordinate change method. We were confirmed by the simulation that the proposed system improves the BER performance.

Performance Analysis of Beamforming Satellite System Applying Circular Array Antenna (원형 형상 배열 안테나를 적용한 위성 빔형성 시스템 성능 분석)

  • Kim, Tae-Yun;Hwang, Suk-Seung
    • The Journal of the Korea institute of electronic communication sciences
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    • v.14 no.5
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    • pp.845-852
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    • 2019
  • The main goal of Signal Intelligence (SIGNT) based on a satellite is to collect valid and accurate data without the topographical constraints, but, due to the characteristics of the satellite communication, the collected signals are greatly vulnerable to the influence of interference and jamming signals because their power are very low. Therefore, the high performance techniques of estimating the angle of arrivals (AOAs) of the collected signals and suppressing interference signals are required for collecting various signals on the ground employing the satellite. In addition, the high quality of the transmission beam-forming technique is required for accurately transmitting the collected information to a ground control center. In this paper, we present a beam-forming satellite system based on a circular array antenna, considering the above techniques, and evaluate and analysis the performance of the presented beam-forming system through the computer simulation. The circular array antenna structure is expected to effectively employ for the SIGINT system based on a satellite, because it is suitable to be installed in the satellite.