• Title/Summary/Keyword: 주파수 도약신호

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Performance Analysis on the Impact of Mutual Interference and the Interference Suppression Method for CBTC System in the Presence of WPAN System (CBTC시스템과 WPAN시스템의 상호간섭영향 및 간섭신호 억제방안에 대한 성능분석)

  • Kim, Seong Cheol
    • Journal of the Korean Society for Railway
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    • v.15 no.5
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    • pp.454-458
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    • 2012
  • The CBTC(Communication based Train Control) and WPAN(Wireless Personal Area Network) systems employed on 2.4GHz ISM band wireless networks provide complementary service within the same environment. Coexistence between the networks will be impaired if the mutual packets are uncertainty associated the timing or gaussian distance. This paper analyzes the impact of the mutual interference and proposed method to minimize the effect of the WPAN system signals on CBTC system. The performance analysis is illustrated by examining the symbol error rate versus signal to noise interference ratio in terms of carrier frequency offset. The method contributes to reduce the symbol error rate drastically. However it can't be a fundamental solution for the impact on the interference problem. It may be needed for railway only frequency after checking the problems of the current railway frequency.

Design of a Linear PA for the Frequency Hopping Transmitter using the Adaptive Predistortion Linearizer (적응 전치왜곡 선형화기를 사용한 주파수 도약 송신기용 선형 전력증폭기의 설계)

  • 강경원;이상설
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.5
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    • pp.802-809
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    • 2001
  • A linear power amplifier for the VHF frequency-hopping(FH) transmitter using an adaptive predistortion linearizer is designed. An analog polynomial linearizer as predistorter is employed. The recursive least square(RLS) algorithm is employed in the optimization process to minimize the errors between the predistorter and postdistorter output signals. Experimental results show that the adjacent channel power of the designed power amplifier is reduced by of 10 dB.

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M-ary orthogonal CDMA Using Time Hopping Codes (시간도약부호를 사용하는 M진직교 부호분할 다원접속)

  • 김일규;김동인;노종선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.7
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    • pp.1374-1389
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    • 1994
  • In this paper, a novel M-ary orthogonal CDMA scheme which utilizes time hopping codes and binary orthogonal sequences is proposed for personal communication system. Its modulated output signal has the characteristics of greater bandwidth occupancy and lower spectral density level as well. So this scheme is useful for spectrum overlay with existing narrowband communication systems which occupy current radio frequency channels. This paper investigates system characteristics through the analysis of modulated output signal power spectrum, and demonstrates the possibility of spectrum overlay.

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Error Performance of Binary FSK Fast Frequency Hopping(BFSK/FFH) Systems in the Presence of Partial-Band Noise Jamming (부분 대역 전파 방해하에서의 바이내리 FSK 주파수 급도약 통신 시스템의 오차 성능에 관하여)

  • 홍윤기
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.20 no.3
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    • pp.52-60
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    • 1983
  • This paper presents a complete analysis for the derivation of the probability of error for a fast (or multiple-hops per bit) frequency hopping spread spectrum system employing binary FSK modulation and noncoherent reception in the presence of partial-band noise jamming and thermal noise. The worst-case error rate performances were obtained numerically and presented as a function of E /N with L as a parameter, where E /N and L are the signal bit energy-to-jamiming density ratio and the number of hops per bit, respectively.

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안티포달(Antipodal) 초광대역 통신 시스템

  • 이정석;김유창;가민호
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.3
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    • pp.63-73
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    • 2002
  • 초광대역 통신 시스템은 광대역에 걸쳐 주파수 스펙트럼이 기저 대역 잡음과 같이 존재하여 기존의 통신 시스템에 간섭을 주지 않고 고속의 통신이 가능하며, 반송파를 사용하지 않기 때문에 송.수신기의 소비 전력을 감소시키고 그의 구조를 간략화 시킬 수 있다. 본 논문은 신호의 대칭성에 의해 평균값이 0인 안티포달 초광대역 신호를 구성하고 시간 도약 부호를 이용하여 다중접속, 주파수 영역에서 에너지의 평활화 및 재밍 저항(간섭 제거)을 위 한 초광대역 통신 시스템을 제안하였다. AWGN 및 다중접속 환경에서 안티포달 초광대역 통신 시스템의 오류확률, 다중접속시 전송속도에 대해 수치해석을 통해 시스템의 성능을 분석하였다.

A Study on the Implementation of Exciter in VHF Band (VHF대역 Exciter 구성에 관한 연구)

  • 박순준;황경호;박영철;정창경;차균현
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.13 no.3
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    • pp.239-254
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    • 1988
  • In this paper an exciter which performs modulation and amplification is composed of high power(30dBm) VCO(Voltage Controlled Oscillator) using push-pull circuit. Modulation is FSK using PLL(Phase Locked Loop). A single loop PLL synthesizer having sequency range of 42.5-100.5MHz, 25KHz channel spacing and switching time of 1msec converts down the exciter VCO frequency to 1.25MHz. This signal mixed with the FSK modulated signal coming in the phase detector of exciter. The acquisition time of exciter for frequency hoppng is less than 200usec, so the total acquisition time for transmission is less that 1.5msec. There is no need of additional power amplification because power amlifiction by high power VCO is high enough to communicate within near distance. The proposed frequency synthesizer is not complex so it is suitable for low cost slow frequency hopping spread spectrum communication.

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Adaptive Decoding Scheme of Concatenated Codes for Frequency-Hopped Spread-Spectrum Communications with a Pulse-Burst Jamming (펄스형 Jamming 신호가 존재하는 주파수 도약 대역확산 통신환경에서 쇄상부호 시스템의 적응 복호화 방식)

  • 김정곤;김성대;김형명
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.7
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    • pp.1234-1243
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    • 1994
  • We propose an adaptive decoding scheme for a concatenated codes with frequency-hopped spread-spectrum communication system in the presence of a pulse-burst jammer and its performance is analyzed. Concatenated coding system employing binary inner code and Reed-Solomon outer code is investigated and the use of side information is allowed to decode both erasures and errors. Our scheme makes the decoder adapts to the level of jamming by switching between two decoding modes such that the overall block error probability can be reduced. It is shown that the proposed decoding scheme yields a significant performance improvement over a conventional decoding scheme.

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UWB Communication and Ranging System using Frequency Slope Modulated Chirp (주파수 효율 및 성능 향상을 위한 Frequency Slope Modulated Chirp 신호를 이용한 UWB 시스템)

  • Kim, Jung-Hyun;Kim, Ji-Hyun;You, Cheol-woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.2A
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    • pp.127-132
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    • 2011
  • This paper proposes a ranging and communicating system that uses the UWB frequency slope modulated chirp signal. Instead of using only the up-chirp and down-chirp with the same frequency sweeping rate, the proposed system uses several chirps that have different frequency sweeping rates with frequency hopping. This system performs better than the conventional communication and ranging schemes because it is capable of increasing the data transmission rate and at the same time decreasing the interference between sequences used by users. In this paper, we propose simulations of UWB communication system to show validity by using the MATLAB.

A Slow Frequency Hopping Transmission Method using Carrier Superpositioning and Frequency Diversity for the Satellite Datalink (저속 주파수 도약 방식 위성 데이터링크에서 송수신 신호중첩 및 주파수 다이버시티 적용)

  • Kim, Ki-Keun;Lee, Min-Woo;Lim, Jae-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.11A
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    • pp.924-932
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    • 2011
  • In this paper, we propose a possibility of usage of carrier superpositioning scheme for a specific slow frequency hopping(SFH) transmission method for the satellite data link in which all of hopping carriers have to be synchronized to DSM transponder of our previous work and usage of frequency diversity in the saved frequency to overcome the SFH disadvantage against jammer. We have analyzed anti-jamming performance and LPI performance and confirmed that the proposed scheme can support data service with 18.5dB processing gain against the worst case partial band jamming and give 2.5dB gain in the LPI performance against D&M detector which can estimate the data rate of unknown signals.

The Proposal of Efficient Hit Prevention Technique according to the Frequency Hopping Pattern in Orthogonal Multi-Carrier FH/CDMA System (직교 멀티캐리어 FH/CDMA 시스템에서 주파수 도약 패턴에 따른 효율적인 충돌 방지 기법 제안)

  • 이문승
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.2
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    • pp.141-150
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    • 2002
  • In this paper, we composed orthogonal multi carrier FH/CDMA system using frequency hopping sequence. Considering hit possibilities by delayed other user's signals we searched the optimal number of user access carrier slots not to influence on performance deterioration with the variation of number of carrier slots according to the number of user access carrier slots. A]io, we evaluated the BER performance improvement due to TCM and Concatenated coding technique by computer simulation.