A New Short-Time DFT FSK Demodulation Method for LEO Satellite Communications Systems

Attapol WANNASARNMAYTHA  Shinsuke HARA  Norihiko MORINAGA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E79-B   No.10   pp.1592-1597
Publication Date: 1996/10/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Satellite Communication
Keyword: 
LEO,  Short-Time Discrete Fourier Transform,  frequency offset,  differential FSK,  

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Summary: 
This paper presents a new Frequency Shift Keying (FSK) demodulation method using the Short Time-Discrete Fourier Transform (ST-DFT) analysis to combat large frequency offset with time variation in low earth orbit (LEO) satellite communications systems. This demodulation method can demodulate the received signal only by searching for the instantaneous spectrum energy peaks without complicated carrier recovery. In addition, it is insensitive to the signal-to-noise ratio (SNR) degradation caused by the excessively wide bandwidth of the receiver front-end band pass filter. Furthermore, the ST-DFT analysis combined with a differential encoding scheme gives FSK demodulation method a potential robustness against large and fast time-varying frequency offset.