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이동 통신 채널에서 직교 주파수 분할 다중 시스템의 성능 연구
김윤희,송익호,김상우,방영조 한국방송공학회 1996 한국방송공학회 학술대회 Vol.1 No.1
In this paper, we first analyze the influence of interference due to the time variation and delay spread of the mobile channel on an orthogonal frequency division multiplexing (OFDM) system. With the result, we obtain the bit error rate performance of the 16-QAM OFDM system. Second, we investigate the performance of the Reed-Solomon (RS) coded 16-GRAM OFDM system when the number of subcarriers varies. In the investigation, we assume that the information transmission rate and the total bandwidth expansion due to coding, guard interval, and the number of subcarriers are fixed. Under this condition, it is observed that there are optimum numbers of subcarriers that minimize the post decoding symbol error probability of RS code for various channel states.
김홍직,송익호,김상우,한진희 한국방송공학회 1996 한국방송공학회 학술대회 Vol.1 No.1
A multi-media binary DS/CDMA system with variable processing gain and coherent correlation receivers are considered under additive white Gaussian noise channels. Two types of information sources with different rates and transmitting powers are assumed to be transmitted simultaneously in the same channel. Average signal-to-noise ratios at the correlation receiver outputs for each type of information sources are analytically derived as functions of discrete partial cross-correlations between spreading code sequences. The analysis is expected to provide analytical tools for use in preliminary system design and spreading code selection.