This paper presents a multicarrier demodulator (MCD) for FDM systems, which is based on the fast Fourier transform (FFT) technique. We show that, without pulse shaping, user's synchronization errors and Doppler shifts imply the use of weighting functions or guard time on the received symbols. Both techniques, evaluated through computer simulations, lead to a loss in SNR and spectral efficiency. The next step is to study a possible coherent QPSK mode in order to oppose these losses. Because of the small number of symbols per hop, coherent demodulation is not an easy task. We present a demodulation technique, based on a feedback principle, that shows little loss compared to the theoretical QPSK performance and resists high enough Doppler values.
Multicarrier demultiplexing and demodulation for an MDR frequency hopped satcom system: simulation analysis
MILCOM, MILCOM, 1997 ; 1 ; 143-147
1997
5 Seiten, 2 Quellen
Conference paper
English
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