• Title, Summary, Keyword: Fade Margin

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A Protection Ratio with Composite Fade Margin for Detailed Frequency Coordination in Microwave Relay System Network

  • Suh, Kyoung-Whoan
    • Journal of electromagnetic engineering and science
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    • v.7 no.2
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    • pp.83-90
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    • 2007
  • In this paper, the formulation of the protection ratio based upon a composite fade margin and availability is newly presented for the detailed planning of frequency coordination in the microwave relay system network, and computed results for co-channel and adjacent channel protection ratios are illustrated over an actual system with 6.2 GHz. It is shown that the protection ratio to assure a quality of service can be expressed in terms of the composite fade margin, noise-to-interference ratio, net filter discrimination, and system parameters. In addition, the net filter discrimination, depending upon the transmitter spectrum mask and the overall receiver filter characteristic, has been examined to investigate the effect of the adjacent channel protection ratio caused by the adjacent channel interference. Regarding simulated results for 6.2 GHz, 60 km, 64-QAM, and N/I=6 dB at the bit error rate of $10^{-6}$, composite fade margin and co-channel protection ratio yield 25.14 and 50.3 dB, respectively. Also, the net filter discrimination of 26.5 dB and the adjacent channel protection ratio of 23.8 dB are obtained at the first adjacent channel of 30 MHz. The proposed method provides some merits in view of a comprehensive and practical application with more detailed and various system parameters needed to access the criteria for making the proper frequency coordination.

Derivation of Protection Ratio and its Calculation for Microwave Relay System Based upon Composite Fade Margin and Availability (합성 페이드 마진 및 가용율에 근거한 M/W 중계 시스템의 보호비 유도 및 계산)

  • Suh, Kyoung-Whoan;Lee, Joo-Hwan
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.18 no.3
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    • pp.341-350
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    • 2007
  • In this paper, the derivation of protection ratio is newly proposed for the detailed planning of frequency coordination in microwave relay networks, and computed results for protection ratio of co-channel and adjacent channel are illustrated over the actual system and its frequency. It is shown that the suggested method based upon availability prediction can be expressed in terms of composite fade margin, interference-to-noise ratio(I/N), net filter discrimination, and system parameters. According to results, for 6.7 GHz, 60 km, 64-QAM, and I/N= -6 dB at BER $10^{-6}$, composite fade margin and co-channel protection ratio provide 25.5 and 50.7 dB, respectively. Also, net filter discrimination and adjacent channel protection ratio are obtained as 26.3 and 24.4 dB, respectively, at the first adjacent channel of 40 MHz. The proposed method provides some merits in computing protection ratio for microwave relay networks in view of an easy extension and practical applications considering more detailed and various system parameters.

Technical analysis of frequency reallocation to FM broadcasting link system for effective use in 900 MHz band (900MHz 대역의 효율적 이용을 위한 FM 방송 링크 시스템 주파수의 재배치에 대한 기술적 분석)

  • Suh, Kyoung-Whoan;Lee, Joo-Hwan
    • Journal of Broadcast Engineering
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    • v.15 no.1
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    • pp.89-98
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    • 2010
  • In this paper, the technical analyzing methodology has been suggested to preserve the same transmission quality of a M/W system used for FM broadcasting link after the frequency reallocation. The simulation was also performed for the actual M/W system operating in each frequency band, and its results were evaluated in terms of an availability based upon a fade margin. It was confirmed that only if the relative fade margin of more than 2.6 dB at 1700 MHz is provided, the equivalent service quality may be obtained regardless of the frequency reallocation. The suggested method will be expected to be widely used for accessing service quality of the M/W system concerned with the frequency reallocation.

Experimental analysis of frequency reallocation to FM broadcasting link system for effective use in 900 MHz band (900MHz 대역의 효율적 이용을 위한 FM 방송 링크 시스템 주파수의 재배치에 대한 실험적 분석)

  • Lee, Joo-Hwan;Suh, Kyoung-Whoan
    • Journal of Broadcast Engineering
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    • v.15 no.1
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    • pp.99-111
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    • 2010
  • In this paper as a follow-up to Paper I, the required fade margin derived in Paper I to preserve the same service quality has been examined by analyzing system and propagation characteristics as well as measured data. The comparison of the fade margin between simulated and measured results is also performed for the actual operating line-of-sight(LOS) and non-LOS links, and practical usefulness as an analysis tool is revealed by checking service quality of M/W system relevant to frequency reallocation. According to simulated and measured results, there was a little difference for LOS link between Mt. Moodung and Mt. Mangun, but a fairly good agreement was reached for non-LOS link between Andong KBS and transmitter site.

A Study on Calculation of Protection Ratio for Interference Analysis in Fixed Radio Relay Networks (고정 무선중계 망의 간섭 분석을 위한 보호비 계산에 대한 연구)

  • Suh Kyoung-Whoan;Lee Joohwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.43 no.1
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    • pp.133-142
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    • 2006
  • This paper suggests an efficient method of protection ratio(PR) calculation and shows some results of point-to-point radio relay system for frequency coordination. The proposed PR can be expressed as a function of C/N of modulation scheme, noise-to-interference ratio(N/I), multiple interference allowance, fade margins of multi-Path and rain attenuation and net filter discrimination. And PR calculation is performed in view of fade margin, modulation scheme, distance, and interference for actual point-to-point radio relay frequency. According to results for 6.2 GHz, 64-QAM and 60 km at BER 10-6, fade margin and co-channel Protection ratio reveal 41.1dB and 74.9 dB, respectively The merit of presented method provides a systematic and easy calculation by means of PR correction factor related with various parameters and can apply the same concept to frequency coordination of millimeter wave radio relay system.

A Study on Calculation of Protection Ratio for Frequency Coordination in Microwave Relay System Networks (M/W 중계 시스템 망의 주파수 조정을 위한 보호비 계산에 대한 연구)

  • Suh, Kyoung-Whoan;Lee, Joo-Hwan
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.125-130
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    • 2005
  • This paper suggests an efficient method of protection ratio calculation and shows some calculated results applicable to frequency coordination in microwave relay system networks, and the net filter discrimination (NFD) associated with Tx spectrum mask and overall Rx filter characteristics has been examined to obtain the adjacent channel protection ratio. The protection ratio comprises several factors such as C/N of modulation scheme, noise-to-interference ratio, multiple interference allowance, fade margins of multi-path and rain attenuation, and NFD. According to computed results for 6.7 GHz, 64-QAM, and 60 km at BER $10^{-6}$, fade margin and co-channel protection ratio are 41.1 and 75.2 dB, respectively, In addition, NFD for channel bandwidth of 40 MHz reveals 28.9 dB at the first adjacent channel, which results in adjacent channel protection ratio of 46.3 dB. The proposed method provides some merits of an easy calculation, systematic extension, and applying the same concept to frequency coordination in millimeter wave relay system networks.

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A Derivation of Comprehensive Protection Ratio and Its Applications for Microwave Relay System Networks

  • Suh Kyoung-Whoan
    • Journal of electromagnetic engineering and science
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    • v.6 no.2
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    • pp.103-109
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    • 2006
  • This paper suggests an efficient and comprehensive algorithm of the protection ratio derivation and illustrates some calculated results applicable to the initial planning of frequency coordination in the fixed wireless access networks. The net filter discrimination associated with Tx spectrum mask and overall Rx filter characteristic has been also examined to show the effect of the adjacent channel interference. The calculations for co-channel and adjacent channel protection ratios are performed for the current microwave frequency band of 6.7 GHz including Tx spectrum mask and Rx filter response. According to results, fade margin and co-channel protection ratio reveal 41.4 and 75.2 dB, respectively, for 64-QAM and 60 km at BER $10^{-6}$. It is shown that the net filter discrimination with 40 MHz channel bandwidth provides 28.9 dB at the first adjacent channel, which yields 46.3 dB of adjacent channel protection ratio. In addition, the protection ratio of 38 GHz radio relay system is also reviewed for millimeter wave band applications. The proposed method gives some advantages of an easy and systematic extension for protection ratio calculation and is also applied to frequency coordination in fixed millimeter wave networks.

The Analysis of Protection Ratio and Its Effect of Interference-to-Noise Ratio for Digital Microwave System with Diversity

  • Suh Kyoung-Whoan;Jang Won-Gyu
    • Journal of electromagnetic engineering and science
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    • v.6 no.3
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    • pp.189-195
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    • 2006
  • In this paper, the derivation of the protection ratio for the digital microwave system with diversity is newly suggested for a basic guidance of initial planning for frequency coordination, and computational results are presented for an actual radio frequency band. The net filter discrimination has been also examined to see the effect of the adjacent channel protection ratio caused by adjacent channel interference. In addition, the protection ratios for the space or frequency diversity system are analyzed in terms of diversity improvement factors to find out an equivalent allowable noise-to-interference ratio (N/I) from degraded fade margin. According to results for 6.2 GHz system, with the space diversity of 25 m distance between antennas or the frequency diversity of ${\Delta}f/f=0.05$, under 64-QAM and 60 km at BER $10^{-6}$, the protection ratio can be greatly reduced in comparison to the non-diversity system. So, assuming that only the same protection ratio as the non-diversity system is kept, it is shown that the system with diversity may get more interference level of N/I allowing from 9.0 to - 5.9 dB or from 6.0 to - 4.3 dB for the space or frequency diversity. In consequence, it is concluded that the diversity system is more robust or tolerable for interferences or fades, which may play an important role in overcoming N/I to some extent.

Performance Analysis of OFDM/QPSK-DMR System Using One-tap Adaptive Equalizer over Microwave Channel Environments (Microwave 채널 환경에서 단일적응등화기를 이용하는 OFDM/QPSK-DMR 시스템의 성능 분석)

  • 안준배;양희진;조성언;오창헌;조성준
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.3
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    • pp.517-522
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    • 2004
  • In this paper, we have analyzed the performance enhancement of Orthogonal Frequency Division Multiplexing/Quadrature Phase Shift Keying Modulation-Digital Microwave Radio(OFDM/QPSK-DMR) system using Band Limited-Pulse Shaping Filter(BL-PSF) over microwave channel environments. For performance enhancement, the one-tap adaptive equalizer is adopted in the OFDM/QPSK-DMR system and than both BER and signature curve performance are compared with those of single carrier DMR system. Computer simulations confirm that the OFDM/QPSK-DMR system using 16 sub-carrier increase the fade margin about 2 dB over microwave channel environments and that of performance using one-tap adaptive equalizer is highly increased the fade margin as the number of sub-carriers is larger.

Performance A Analysis of OFDM/QPSK-DMR System Using BL-PSF over Microwave Channel Environments (Microwave 채널환경에서 BL-PSF를 적용하는 OFDM/QPSK-DMR 시스템의 성능분석)

  • Ahn, Jun-bae;Yang, Hee-jin;Oh, Chang-heon;Cho, Sung-joon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.9C
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    • pp.1279-1288
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    • 2004
  • In this paper, the DMR(Digital Microwave Radio) system-based OFDM(Orthogonal Frequency Division Multiplexing) scheme in microwave channel environments has been proposed and system performances have been evaluated. The existing single carrier DMR system has a complex system structure due to using high-level QAM(Quadrature Amplitude Modulation) modulation scheme and so charmel capacity is limited by sensitive effects from fading. Therefore, in the proposed DMR system, it uses that the OFDM scheme for enhancement of fading distortion and also uses that the band-limited pulse shaping filter instead of windowing for no additional data such as GI/GB and for using efficient of IFFT/FFT block. The performance of OFDM/QPSK-DMR system and single carrier DMR system are analysed by computer simulation using two-ray model under the microwave channel environments The computer simulation results confirm that the fade margin of the proposed OFDM/QPSK-DMR system is highly increased as the number of sub-carriers is larger.