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Toshinaga, Hideki,Kobayashi, Kiyoshi,Ohata, Kohei,Kazama, Hiroshi 통신위성우주산업연구회 2000 Joint Conference on Satellite Communications Vol.2000 No.-
This paper proposes an interference cancellation scheme for multimedia satellite communication systems, and presents results of hardware experiments on the scheme. In order to achieve higher frequency utilization efficiency, the high-speed TDM forward link signal and the low-speed spread spectrum FDMA return link signals are superposed. The conventional interference cancellation scheme utilizes a replica signal whose amplitude, phase and timing are fixed. It is virtually impossible to adjust them properly because factors such as equipment performance and propagation conditions vary irregularly. The proposed scheme is able to generate an accurate replica by utilizing a delay variation compensator and an adaptive filter. The results of a hardware experiment show that the proposed interference cancellation scheme holds the degradation in the return link signal to less than 3dB, when D/U is greater than -37dB.
토시나가 히데키,고바야시 키요시,오하타 코헤이,우에바 마사즈미,TOSHINAGA, Hideki,KOBAYASHI, Kiyoshi,OHATA, Kohei 통신위성우주산업연구회 2001 Joint Conference on Satellite Communications Vol.2001 No.-
A bi-directional multimedia satellite communication system has been proposed to offer high-speed Internet access links. For efficient use of frequency bandwidth and transponder power, this system employs super-posed transmission scheme, which Spread Spectrum (SS) signals are superposed on the high-speed TDM signal. In order to realize this scheme, two novel technologies are introduced. They are the adaptive interference cancellation technique, and the burst mode SS demodulation technique. This paper describes the results of a system performance evaluation that uses prototypes. The measured results demonstrate that the adaptive interference canceler can eliminate interference in spite of amplitude fluctuation, and also demonstrate that the burst-mode SS demodulator can demodulate without degradation, even if there is carrier frequency error.