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라이안 페이딩 채널에서 길쌈 부호화와 최적 검파 기법이 16 QAM신호의 오율 성능에 미치는 영향
김언곤 大田産業大學校 1996 한밭대학교 논문집 Vol.13 No.0201
In this paper, it has been simulated the symbol error rate(SER) performance of optimum threshold detection (OTD) of the 1/2 convolutional encoded 16 QAM signal in the Rician fading channel when Viterbi decoder is used as channel decoding algorithm at the receiver. With 1/2 convolutional channel coding at the transmitter, according as K, power ratio in the dominant path to the scattered paths, is grown up, we see that OTD is suprier than conventional threshold detection(CTD) with Viterbi decoding algorithm at the receiver.
김언곤 大田産業大學校 1995 한밭대학교 논문집 Vol.12 No.0201
The performance of radio communication signal is degraded by fading ill the radio channel. To reduce the degradation of the performance brought by fading, the diversity technique is generally used. Even though the received signal passes through the diversity circuit, the amplitude variation of recived signal remains. This residual variation acts as a factor of amplitude modulation on each signal level. Further-more, while the signal passes through the relay transmitters, the phase of the signal is contaminated by phase jitter due to incomplete phase synchronization in relay transmitter. In this paper, equations of error rate have been derived and computer simulation has been executed for 16 QAM signal at the ouput of diversity circuit, assuming the distribution of residual amplitude variation is Gaussian and the distribution of phase jitter is sinusoidal. From the obtained results, it is known that the CNR should be over 22 dB, the residual amplitude variation should not exceed 10% and the phase jitter should not exceed 3~4° to maintain the error probability of 10^-3 for voice communication.
무선 페이딩 통신로에서 WATM 시스템의 성능 개선에 관한 연구
김언곤 大田産業大學校 2000 한밭대학교 논문집 Vol.17 No.1
We have evaluated the BER's and CLP's of Wireless ATM (WATM) cells employing the concatenated FEC code through the simulation in wireless channel modeled as a AWGN and a Rician fading channel, respectively. From the results. it is known that the concatenated FEC technique adopting RS code with error correcting capability of 8 showed the optimum performance in AWGN channel. In this case, Eb/No of 2.5 dB was sufficient for obtaining the BER = 10-10 , and the performance improvement of about 4.5 dB was obtained by employing concatenated FEC code rather than the convolutional code of R =1/2, K =7. When the values of K parameter which means the ratio of the direct signal to scattered signal power in Rician fading channel are 6 and 10, it is shown that the performance improvement of about 4 dB and 2 dB is obtained, respectively, in terms of Eb/No by employing the concatenated FEC code considering the maximum tolerance BER of the voice service. Also in Rician fading channel of K=6 and K=10. considering CLP = 10-3 as a criterion, we have known that the performance improvement of about 3.5 dB and 1.5 dB is obtained, respectively, in terms of Eb/ No by employing the concatenated FEC code.
페이딩과 간섭 환경하에서 16 QAM 신호의 성능에 대한 부호화의 영향
김언곤 한밭대학교 산업과학기술연구소 1995 논문집 Vol.3 No.-
It is analyzed that the error performance of BCH coded 16 QAM signal with tone interferer over Rician fading channel. In order to compensate degradations of signal over fading channel, it is used that BCH codes with 63 codeword. And the improvement of error performance is also shown for error-correcting power of 2 to 6. When fading (K=40) and tone interfernce (CIR=30 dB) are weak, the error rate of 10^-3 is obtained at about CNE=21 dB using more than 3 bits error-correcting power but when fading is deep, BCH code of more than 6 bits error-correcting power must be used regardless to tone interference.
나카가미 페이딩과 임펄스 잡음이 공존하는 무선 통신로에서 이동 통신 시스템의 성능 개선에 관한 연구
김언곤,박기식,조성언 大田産業大學校 2000 한밭대학교 논문집 Vol.17 No.1
We have evaluated the BER's and CLP's of Wireless ATM (WATM) cells employing the concatenated FEC code with pilot symbols for fading compensation through the simulation in indoor wiretess channel modeled as a Rayleigh and a Rician fading channel, respectively. The results of the performance evaluation are compared with those obtained by employing the convolutional code in the same condition. In Rayleigh fading channel, considering the maximum tolerance BER (10-3) as a criterion of the voice service, it is known that the performance improvement of about 4 dB is obtained in terms of Eb/No by employing the concatenated FEC code with pilot symbols rather than the convolutional code with pilot symbols. When the values of K parameter which means the ratio of the direct signal to scattered signal power in Rician fading channel are 6 and 10, it is shown that the performance improvement of about 4 dB and 2 dB is obtained. respectively, in terms of Eb/No by employing the concatenated FEC code with pilot symbols considering the maximum tolerance BER of the voice service. Also in Rician fading channel of K=6 and K=10, considering CLP = 10-3 as a criterion, it is observed that the performance improvement of about 3.5 dB and 1.5 dB is obtained, respectively, in terms of Eb/No by employing the concatenated FEC code with pilot symbols.
라이안 페이딩 채널에서 길쌈 부호화와 최적 검파 기법이 16 QAM 신호의 오율 성능에 미치는 영향
김언곤 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-
In this paper, it has been simulated the symbol error rate(SER) performance of potimum thereshold detection (OTD) of the 1/2 convolutional encoded 16 QAM signal in the Rician fading channel when Viterbi decoder is used as channel decoding algorithm at the receiver. With 1/2 convolutional channel coding at the transmitter, according as K, power ratio in the dominant path to the scattered paths, is grown up, we see that OTD is suprier than conventional threshold detection(CTD) with Viterbi decoding algorithm at the receiver
김언곤,신동일,조성준 한국항공대학교 1986 論文集 Vol.24 No.-
Uplink와 downlink 가우스성 잡음이 존재하는 존재하에서 비선형 위성 트랜스폰더(transponder)를 통과하는 DS-BPSK(Direct Sequence-Binary Phase Shift Keying)신호의 오율식을 구했다. 위성 트랜스폰더의 TWT(traveling wave tube)전력 증폭기의 비선형 특성은 이상적인 하드리미터(hard limiter)로 모델링하였다. 구해진 오율식에 의해 컴퓨터 계산을 행하고, 그 결과를 반송파 대 uplink잡음전력비(uplink CNR), 반송파 대 downlink잡음 전력비(downlink CNR) 및 확산 스펙트럼의 처리 이득을 파라미터로 하여 그래프로 나타내고 선형시스템의 경우와 비교ㆍ분석했다. 그 결과 uplink CNR 이 O[dB] 이상일 경우는 비선형시스템이 선형시스템에 비해 downlink CNR 면에서 0.4[dB] 정도의 이득이 있었고, 선형시스템에 대한 비선형시스템의 개선도에 있어서 처리 이득은 그다지 영향을 미치지 못함을 알 수 있었다. The error rate equation of DS-BPSK(Direct Sequence-Binary Phase Shift Keying) signal transmitted through the nonlinear satellite transponder has been derived in the up link and downlink Gaussian noise environment. The nonlinearity of TWT(traveling wave tube) in satellite transponder is modeled as an ideal hard limiter. The numerical results of the derived equations have been shown in figures in terms of carrier to uplink noise power ratio(uplink CNR), carrier to downlink noise power ratio(downlink CNR) and process gain, and compared with those of the linear system. In the analysis, we have known that when the uplink CNR is below -5[dB] the hard-limited system degrades the error rate performance compared with the linear system, however, when the uplink CNR is above O[dB] the hard-limited system can gain 0.4[dB] improvement in downlink CNR to maintain a fixed error rate Pe=10(??) compared with the linear system. Even though the process gain can improve the error rate performance of both systems-the hard-limited system and the linear system, it does not affect seriously the improvements of the hard-limite system performance over the linear system performance.