• Title, Summary, Keyword: Wideband

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Designing of efficient super-wide bandwidth extension system using enhanced parameter estimation in time domain (시간 영역에서 개선된 파라미터 추론을 통한 효율적인 초광대역 확장 시스템 설계)

  • Jeon, Jong-jeon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.431-433
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    • 2018
  • This paper proposes the system that offer super-wideband speech which is made by artificial bandwidth extension technique using wideband speech signal in time-domain. wideband excitation signal and line spectrum pair(LSP) are extracted based on source-filter model in time-domain. Two parameters are extended by each bandwidth extension algorithms, and then, super-wideband speech parameters are estimated. and synthesized. Subjective test shows super-wideband speech is better speech quality than wideband speech signal.

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Compact and Wideband Fylfot-Shaped Planar Monopole Antenna

  • Shim, Jae-Ruen
    • Journal of information and communication convergence engineering
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    • v.7 no.4
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    • pp.449-452
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    • 2009
  • In this paper, a novel compact and wideband fylfot-shaped planar monopole antenna is proposed. The fylfot-shaped is suggested to reduce the volume of a general crossed planar monopole antenna. The volume of the proposed antenna is about 1/4 of a general crossed planar monopole antenna under the conditions where the wideband characteristics are maintained. This technique is suitable for the design of wideband planar monopole antenna which needed a small volume.

A Study on the Architecture of Narrowband/Wideband Switching Networks (협대역/중대역 스위치망의 구성 방안)

  • Sung, Dan-Keun;Kim, Seung-Hwan
    • Proceedings of the KIEE Conference
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    • pp.497-501
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    • 1988
  • In this study we consider three types of accomodation methods of narrowband/wideband services. The fully integrated accomodation method is sufficient to accomodate the relatively low wideband traffic and the partially integrated method is required to meet the specification of blocking probability as the wideband traffic increases. The segregated accomodation method is required expecilly in case of the high wideband traffic demand.

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A Dynamic QoS Model for improving the throughput of Wideband Spectrum Sharing in Cognitive Radio Networks

  • Manivannan, K.;Ravichandran, C.G.;Durai, B. Sakthi Karthi
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.11
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    • pp.3731-3750
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    • 2014
  • This paper considers a wideband cognitive radio network (WCRN) which can simultaneously sense multiple narrowband channels and thus aggregate the detected available channels for transmission and studies the ergodic throughput of the WCRN that operated under: the wideband sensing-based spectrum sharing (WSSS) scheme and the wideband opportunistic spectrum access (WOSA) scheme. In our analysis, besides the average interference power constraint at PU, the average transmit power constraint of SU is also considered for the two schemes and a novel cognitive radio sensing frame that allows data transmission and spectrum sensing at the same time is utilized, and then the maximization throughput problem is solved by developing a gradient projection method. Finally, numerical simulations are presented to verify the performance of the two proposed schemes.

Efficient Codebook Search Method for AMR Wideband Speech Codec (광대역 AMR 음성 압축기를 위한 효율적인 코드북 검색 방법)

  • 김윤희;박호종
    • The Journal of the Acoustical Society of Korea
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    • v.22 no.4
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    • pp.308-314
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    • 2003
  • Wideband speech communications with 7㎑ bandwidth can provide high-quality speech services that are almost impossible with current narrow-band speech communications with 3.4 ㎑ bandwidth, and AMR wideband codec was recently developed for these services. The performance of AMR wideband codec is excellent due to its wideband information and partially to ACELP structure, but it requires high computational complexity especially in codebook search. In this paper, to solve this problem, an efficient codebook search method for AMR wideband codec is proposed. The proposed method first determines the coarse initial codevector, then improves the performance of codevector by replacing a poor pulse in codevector with better one iteratively. Simulations show that AMR wideband codec with proposed codebook search method has higher performance with much less computational cost than conventional AMR wideband codec.

Interference Evaluation between competiting Wideband CDMA systems

  • Kwon, Dong-Seung;Han, Jin-Kyu;Park, Han-Kyu
    • Proceedings of the IEEK Conference
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    • pp.121-124
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    • 2000
  • In this paper, we evaluate the interference statistics between the competiting wideband CDMA systems, and optimize the frequency coordination between Wideband-CDMA systems by the Monte-Carlo methodology. We develop the simulator to analyze the radio interference between CDMA systems. It can calculate or estimate the probability of interference from adjacent frequency band, which is also power controlled. We simulate the interference effects between two Wideband CDMA systems. We present the required carrier distance and zone for two operators to meet the required coverage efficiency and outage probability of Signal to interference plus noise ration (SINR).

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Wideband Capon Beamforming for a Planar Phased Radar Array with Antenna Switching

  • Lee, Moon-Sik
    • ETRI Journal
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    • v.31 no.3
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    • pp.321-323
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    • 2009
  • A wideband beamforming algorithm for estimating the azimuth angle, elevation angle, velocity, and range using a planar phased radar array with antenna switching is proposed. It uses the time-variant steering vector model. Simulation results illustrating the performance of the proposed beamformer are presented.

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Chirp-Based Cognitive Ultra-wideband Radio

  • Shen, Hanbing;Zhang, Weihua;Kwak, Kyung-Sup
    • ETRI Journal
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    • v.29 no.5
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    • pp.676-678
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    • 2007
  • In this letter, we propose a cognitive ultra-wideband radio scheme which is based on a modified chirp waveform. Therefore, it requires only time domain processing in the cognitive radio systems and reduces system complexity and power consumption.

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A Wideband Circularly Polarized Pinwheel-Shaped Planar Monopole Antenna for Wireless Applications

  • Lee, Wang-Sang;Oh, Kyoung-Sub;Yu, Jong-Won
    • Journal of electromagnetic engineering and science
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    • v.12 no.2
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    • pp.155-160
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    • 2012
  • A wideband circularly polarized pinwheel-shaped planar monopole antenna fed by a wideband feeding network is presented in this paper. The proposed antenna is formed by four wideband planar monopole antenna elements with aquadruple feeding network in order to improve the performance of circular polarization. Additionally, the antenna, which is introduced here, has a high gain in the z axis direction because of its folded antenna structure. The attractive characteristics of the proposed antenna are the wide impedance bandwidth of 87.3 % (1 GHz to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 92.3 % (1.05 GHz to 2.85 GHz), and the maximum gain within the 3 dB AR bandwidth is about 8.24 dBic.

Quickest Spectrum Sensing Approaches for Wideband Cognitive Radio Based On STFT and CS

  • Zhao, Qi;Qiu, Wei;Zhang, Boxue;Wang, Bingqian
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.3
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    • pp.1199-1212
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    • 2019
  • This paper proposes two wideband spectrum sensing approaches: (i) method A, the cumulative sum (CUSUM) algorithm with short-time Fourier transform, taking advantage of the time-frequency analysis for wideband spectrum. (ii)method B, the quickest spectrum sensing with short-time Fourier transform and compressed sensing, shortening the time of perception and improving the speed of spectrum access or exit. Moreover, method B can take advantage of the sparsity of wideband signals, sampling in the sub-Nyquist rate, and it is more suitable for wideband spectrum sensing. Simulation results show that method A significantly outperforms the single serial CUSUM detection for small SNRs, while method B is substantially better than the block detection based spectrum sensing in small probability of the false alarm.