• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.9
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• pp.37-43
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• 2010

An Interference Cancellation Wireless Repeater transmitts directly amplified the RF signal input to extend the coverage of the base station. Such a repeater inevitably suffers from the feedback interferences due to the environment and the adaptive Interference Cancelling System(ICS) is necessary. In this paper, the Variable Stepsize Complex Sign -Sign(VSCSS) LMS algorithm for ICS is presented. The algorithm can be implemented without multiplication/division arithmetic operation so that the required logic resources can be dramatically reduced in FPGA implementation. The performance of the proposed algorithm was analyzed in comparison with CSS-LMS algorithm and the learning curves obtained from simulation showed an excellent agreement with the theorical prediction. The simulation result with ICS in fading feedback channel environment showed the performance of the proposed algorithm is competible with NLMS algorithm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.427-432
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• 2010

To reduce the outage probability and to increase the transmission capacity, the importance of repeaters in cellular systems is increasing. But a RF(Radio Frequency) repeater has a problem that the output of the transmit antenna is partially feedback to the receive antenna, which is feedback interference. In this paper, we proposed adaptive Sign-Sign LMS(Least Mean Square) algorithm using correlations for the performance enhancement of RF repeater. The weight vector is updated by using sign of input signal and error signal to the least squared error of the conventional algorithms. When compared with the conventional method, the proposed canceller achieves the maximum 10 dB performance gain in terms of the MSE(Mean Square Error).

• Journal of Advanced Navigation Technology
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• v.6 no.4
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• pp.273-278
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• 2002

In this paper, we provide the Interference Canceller Systems(ICS) in the wireless environments in the presence of co-existing ETACS and CDMA digital cellular systems to effectively cancel the interference than the established canceller systems. We proved the enhanced cancelling performances more than 29 dB cancellation characteristics between co-existing ETACS and CDMA digital cellular systems and the stabilized system characteristics in the rapidly changing wireless circumstances.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.11
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• pp.32-39
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• 2009

In this thesis, design effective elimination interference algorithm of ICS repeat system for repeater that improve frequency efficiency. Gennerally, LMS Algorithm apply to ICS repeat system. Error convergence speed and accuracy of LMS Algorithm are influenced by reference signal. For improve LMS Algorithm, suggest Adaptive searching channel estimate algorithm. For using channel characteristic, adaptive searching channel estimate algorithm make reference signal similar interference signal by convolution operation and complement LMS algorithm demerit. For make channel similar pratical channel, apply Jake's Rayleigh multi-path model. LMS algorithm and suggested adaptive searching channel estimate algorithm that have 16 taps apply to ICS repeat system under Rayleigh multi-path channel, so simulate with MATLAB. According to simulate, ICS repeat system with LMS algorithm show -40 dB mean square error convergent after 110 datas iteration and ICS repeat system with adaptive searching channel estimate algorithm show -80 dB mean square en-or convergent after 120 datas iteration. Analyze simulation result, suggested adaptive searching channel estimate algorithm show 40 dB accuracy than LMS algorithm.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.97-104
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• 2016

In this paper, in order to relieve the area of terrestrial DTV broadcasting, we watch the same channel DTV Repeater output ICS using nano field test and analysis of effect was proven. Interspersed throughout the blanket area(natural) and buildings(artificially) 7 established the field selected as the test area, and each station(KBS1, KBS2, MBC, SBS, EBS) Extremely Low Power ICS Repeater the same channel of the receiving field strength and after install, SNR(Signal to Noise Ratios) verify the equipment to measure the efficacy and minimal output for future ICS type nav should you wish to provide a research-based for the spread.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.295-302
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• 2011

In this paper we consider technological requirements to broadcast digital television signals using single frequency networks(SFN) in the Advanced Television Systems Committee(ATSC) transmission systems and propose Interference Cancellation Digital On Channel Regenerative Repeater(IC-DOCR) thar overcomes the limitation of EDOCR(Equalization Digital On Channel Repeater) proposed by ETRI. The proposed IC-DOCR maintains the benefits of EDOCR that have good output signal quality removing multi-path, additive white Gaussian noise(AWGN). In additional, since the Interference Cancellation algorithm using the 8-VSB symbol demodulation of received signal removes the Interference of feedback signal, IC-DOCR improve the weakness of EDOCR that have low isolation between receive and transmit antenna so that can overcome the limitation of output signal power. we did analysis and verification of the proposed system performance using computational simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.464-470
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• 2000

In this paper, we introduce a modified interference cancellation scheme to overcome MAI(Multiple Access Interference) in DS-CDMA. Among ICs(Interference Cancellers), PIC(Parallel Interference Canceller) requires the more stages to have the better BER(Bit Error Rate), and SIC(Successive Interference Canceller) faces the problems of power reordering and large delays. To resolve the problems of them, we propose a modified interference cancellation scheme combining SIC and PIC. The proposed interference canceller has improved the performance through the total received signal applied sorting method is fed into the initial stage. Its structure extracts the good characteristics because of the input signal removed MAI in the initial stage. The characteristics of the proposed system are as follows (1) smaller delay, and the strongest user signal is also reduced to MAI(unlike SIC), (2) it has the good BER performance only using fewer stages (unlike PIC).

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.117-118
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• 2007

The received signal of ICS repeater is composed of BS(Base Station) and feedback signals. In this case, if the feedback signal is not rejected, system is oscillated. we use the IF signal for rejecting the feedback signal at ICS system. In general, SAW filter is used to reject the image of If signal. the use of this filter generates the system delay problems. In this paper, instead of SAW filter we use the Hilbert transform for rejecting image signal.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.19-25
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• 2009

In this thesis, design effective elimination interference algorithm of ICS repeat system for repeater that improve frequency efficiency. Error convergence speed and accuracy of LMS Algorithm are influenced by reference signal. For improve LMS Algorithm, suggest Adaptive channel estimate algorithm. For using channel characteristic, adaptive channel estimate algorithm make reference signal similar interference signal by convolution operation and complement LMS algorithm demerit. For make channel similar piratical channel, apply Jake's Rayleigh multi-path model that random five path with 130Hz Doppler frequency. LMS algorithm and suggested adaptive channel estimate algorithm that have 16 taps apply to ICS repeat system under Rayleigh multi-path channel, so simulate with MATLAB. According to simulate, ICS repeat system with LMS algorithm show -40dB square error convergent after 150 datas iteration and ICS repeat system with adaptive channel estimate algorithm show -80dB square error convergent after 200 datas iteration. Analyze simulation result, suggested adaptive channel estimate algorithm show more three times iteration performance than LMS algorithm, and 40dB accuracy.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.805-810
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• 2019

Recently, a majority of 4G mobile telecommunication manufacturers prefer repeaters with good adaptability. In this paper, we propose a new LMF(: Least Means Fourth) algorithm for LTE(: Long Term Evolution) RF(: Radio Frequency) Repeater. The proposed algorithm is a modification of the LMF, which appropriately adjusts the step size and improves performance according to the Sign function. The steady state MSE(: Mean Square Error) performance of the proposed LMF algorithm with step size of 0.009 is low level at about -25dB, and the proposed LMF algorithm requires 500 less iterations than the conventional algorithms at MSE of -25dB.