• Title/Summary/Keyword: Gaussian channel

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An Efficient FTN Decoding Method using Separation of LDPC Decoding Symbol in Next Generation Satellite Broadcasting System (차세대 위성 방송 시스템에서 LDPC 복호 신호 분리를 통한 효율적인 FTN 복호 방법)

  • Sung, Hahyun;Jung, Jiwon
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.2
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    • pp.63-70
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    • 2016
  • To increase throughput efficiency and improve performance, FTN(Faster Than Nyquist) method and LDPC(Low Density Parity Code) codes are employed in DVB-S3 system. In this paper, we proposed efficient turbo equalization model to minimize inter symbol interference induced by FTN transmission. This paper introduces two conventional scheme employing SIC(Successive Interference Cancellation) and BCJR equalizer. Then, we proposed new scheme to resolve problems in this two conventional scheme. To make performance improved in turbo equalization model, the outputs of LDPC and BCJR equalizer are iteratively exchange probabilistic information. In fed LDPC outputs as extrinsic informa tion of BCJR equalizer. we split LDPC output to separate bit probabilities. We compare performance of proposed scheme to that of conventional methods through using simulation in AWGN(Additive White Gaussian Noise) channel. We confirmed that performance was improved compared to conventional methods as increasing throughput parameters of FTN.

a Study on the Hybrid Interference Canceller for MAI Cancellation (다중접속간섭 제거를 위한 혼합형 간섭제거기에 관한 연구)

  • Kim, Jae-Hong;Park, Yong-Wan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.37 no.4
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    • pp.9-16
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    • 2000
  • This paper shows the performance of a multiuser detection DS-CDMA receiver based on of the hybrid scheme of parallel interference cancellation (PIC) and successive interference cancellation (SIC). The proposed hybrid interference cancellation is presented and is compared with existing PIC, SIC and Hybrid It of other type schemes. The performance criteria used for comparison are complexity, delay and average bit error rate (BER) performance obtained by simulation in Rayleigh-fading channel (Jake's model) with additive white Gaussian noise (AWGN). In the proposed hybrid IC, the BER performance approximates the one of SIC and the delay is half of the SIC. And the number of cancellation of the hybrid It is reduced about a fourth.

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A Trellis-Coded 3-Dimensional OFDM System (격자 부호화 3차원 직교 주파수분할다중화 시스템)

  • Li, Shuang;Kang, Seog Geun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.9
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    • pp.1635-1641
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    • 2017
  • In this paper, a trellis-coded 3-dimensional (3-D) orthogonal frequency division multiplexing (OFDM) system is presented and its performance is analyzed. Here, a set-partitioning technique for trellis coding with respect to a 3-D signal constellation is also presented. We show theoretically that the proposed system, which exploits a trellis coding scheme with recursive systematic convolutional codes (RSC) of code rate R = 1/3 and 2/3, can improve symbol error rate (SER) up to 7.8 dB as compared with the uncoded OFDM system in an additive white Gaussian noise (AWGN) channel. Computer simulation confirms that the theoretical analysis of the proposed system is very accurate. It is, therefore, considered that the proposed trellis-coded 3-D OFDM system is well suited for the high quality digital transmission system without increase in the available bandwidth.

Suppression Circuit Design of interference Using Orthogonal Signal (직교신호를 이용한 간섭 억제회로 설계)

  • Yoon, Jeoung-Sig;Chong, Jong-Wha
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.10A
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    • pp.969-979
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    • 2002
  • This paper proposes an novel method of minimizing Interference which causes data decision error in digital wireless communications. In this method, in order to suppress ISI which is caused by the phase difference between the transmitted and received signal phases, the transmitted and received signals are always kept orthogonal by compensating the transmitted signal for detecting the phase noise and the delay of the received signal was implemented by MOS circuits. To delay the phase of the signal, additive white Gaussian noise (AWGN) environment was used. The phase and delay of the signal transmitted through AWGN channel were compensated in the modulator of the transmitter and the compensated signal was demodulated using quasi-direct conversion receiver and QPSK demodulator. ISI suppression was achieved by keeping the orthogonality between the compensated transmitted signal and the receive signal. The error probability of data decision was compared. By simulation the proposed system was proved to be effective in minimizing the ISI.

Performance of Serial Concatenated Convolutional Codes according to the Concatenation Methods of Component Codes (구성부호의 연접방법에 따른 직렬연접 길쌈부호의 성능)

  • Bae, Sang-Jae;Lee, Sang-Hoon;Joo, Eon-Kyeong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.1A
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    • pp.18-25
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    • 2002
  • In this paper, the performance of three types of serial concatenated convolutional codes (SCCC) in AWGN (additive white Gaussian noise) channel is compared and analyzed. As results of simulations, it can be observed that Type I shows the best error performance at lower signal-to-noise ratio (SNR) region. However, Type III shows the best error performance at higher SNR region. It can be also observed the error floor that the performance cannot be improved even though increasing of the number of iterations and SNR at Type I. However, the performance of Type II and Type III are still improved over the five iterations at higher SNR without error floor. And BER performance of three types can be closed to upper bound of three types with increase of SNR. It can be also observed that the upper bound of Type III shows the best performance among the three types due to the greatest free distance.

A Study on the Diversity Reception Performance of Spread Spectrum Signals in Interference and Fading Environments (간섭과 페이딩환경에서 스펙트럼 확산(SS) 통신 신호의 다이버시티 수신 특성에 관한 연구)

  • 강희조;이권현;조성준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.19 no.5
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    • pp.901-911
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    • 1994
  • The error performance of M-ary differential phase shift keying (MDPSK) through m-distribution fading channel in hybrid direct sequence/slow frequency hopped spread spectrum multiple access (DS/SFH-SSMA) systems has been evaluated, and also the error probability has been evaluate when adopting diversity technique and coding technique. From the results, we know that the error performance more deteriorates as depth of fading becomes deeper. In Rayleigh fading environment (m=1), increasing of the number of frequency hopping (q) reduces the effect of multiple access interference, because it decreases the probability a hit. When q is much larger than the number of user (K), the probability of error in high E/N region is dominated by the multipath interference while the multiple access interference is negligible. In lower E/N region, the probability of error is independent of q because the effect of gaussian noise becomes dominat.

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Error Rate Performance of DS-BPSK Signal transmitted through a Hard-Limiting Satellite Channel in the presence of Interference and Noise (간섭과 잡음이 존재하는 Hard-Limiting 위성채널상에서의 DS-BPSK신호의 오율특성)

  • 신동일;조성준
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.11 no.1
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    • pp.64-72
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    • 1986
  • The error rate equation fo DS-BPSK(Direct Sequence Binary Phase Shift Keying) signal transmitted through the nonlinear satellite transponder has been derived in the cochannel interference and downlink Gaussian noise environment. The input to the satellite transponder is the superposition of DS-BPSK signal with one interfere which is a cochannel wide-band PN signal. The error rate performance of DS-BPSK system has been evaluated and shown in figures in terms of carrier to interference power ratio(CIR), downlink signal to noise power ratio(downlink SNR) and process gain. In the analysis, it has been shown that the use of a hard limiter in DS-BPSK satellite system leads to the generation of narrow-band intermodulation products which is independent of the process gain. Also it is known that the error rate performance can be improved in the low levels (below 10dB) of CIR as the CIR increase. As the process gain varies from 10 to 100 the curve gives the about 10 dB gain in downlink SNR to maintain a fixed error rate.

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A Study on the Performance Characteristics of a Chirp RTLS over Wireless Channel with Gaussian Noise (가우시안 잡음이 존재하는 무선채널에서 Chirp RTLS 시스템의 성능 특성에 관한 연구)

  • Kang, Byeong-Gwon
    • Journal of Digital Convergence
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    • v.11 no.7
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    • pp.201-207
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    • 2013
  • The chirp signaling has been mainly used in radar systems due to its good correlation characteristics, and nowadays it is applied to real time locating system(RTLS). The RTLS with chirp signaling was chosen as a standard such as ISO/IEC 24730-5 and IEEE 802.15.4a. In this paper, the performance of a real time locating system with chirp signaling was evaluated and simulated with relative distance error rates. We considered three cases of S/I = -30[dB], -20[dB], and -10[dB] with Rician factor K=10 and K=20. The performance was enhanced with K factor improvement by 25%, 27% and 50% for respective three cases of S/I. As results, in case of S/I < -20[dB], the minimum signal power is required for performance improvement even though the line of sight component is helpful. And also, in case of S/I ${\geq}$ -20[dB], as the line of sight component is stronger the better performance is obtained.

Blind MOE Interference Canceller for Multicarrier DS-CDMA Systems (다중 반송파 DS-CDMA 시스템을 위한 블라인드 MOE 간섭 제거기)

  • Woo Dae Ho;Byun Youn Shik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.10C
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    • pp.1395-1401
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    • 2004
  • In The objective of this paper is to apply blind minimum output energy multiuser detection method to multicarrier direct sequence code division multiple access system. The performance of MC/DS-CDMA is reduced due to multiple access. To increase the performance of system, we need to cancel multiple user components. Blind interference canceller is able to detect the desired's information with the only minimal information of the desired user. We evaluate the performance of the proposed receiver under Gaussian channel. Simulation results show that the proposed receiver has about 6[dB] gain of signal to noise ratio without multiple user interference and has about 3[dB] gain of SNR with multiple user interference. Also, the result of comparing the capacity of the active users shows that the proposed method has about 2 times capacity more than conventional method. As a conclusion, simulation results show that the proposed method has better performs better than conventional method.

The Performance Analysis of DS/SSMA BPSK Correlation Receivers in Electric Power Line Channel (전력선 채널에서의 DS/SSMA BPSK 코릴레이션 수신기 성능에 관한 연구)

  • Kang, Byeong-Kwon;Cho, Chang-Gil;Cho, Kwan;Lee, Jae-Kyeong;Whang, Keum-Chan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.17 no.9
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    • pp.972-981
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    • 1992
  • In this paper, the performance of linear and hard-limiting correlation receivers for DS/SSMA BPSK power line communication system is analyzed. Strong impulsive noise of power line is modeled with Chan's noise model, and the performance of both receivers is analyzed in terms of parameters such as ratio of power spectrum density of impulsive noise to that background noise, ratio in impulsive noise width th that of data bit, and interarrival time of impulsive noise. And also multiple access capacity is evaluated with Gaussian approximation of multiple access interference. The results of this analysis reveal that the performance of linear correlation receiver is superior to that of hard-limiting correlation receiver when $N_1/N_b$ is small and is close to 1. But the BER and the multiple access capacity of hard-limiting correlation receiver becomes better in comparison with linear correlation receiver as $N_1/N_b$ increases.

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