Title :
Two-step Kalman-filter-based AFC for direct conversion-type receiver in LEO satellite communications
Author :
Wannasarnmaytha, Attapol ; Hara, Shinsuke ; Morinaga, Norihiko
Author_Institution :
Nokia Telecommun. Ltd., Bangkok, Thailand
fDate :
1/1/2000 12:00:00 AM
Abstract :
We present a new two-step automatic frequency control (AFC) suited for direct conversion-type receivers to counteract large frequency offset with time variation in low Earth orbit (LEO) satellite communication systems. The proposed AFC scheme based on the Kalman-filter provides two steps of frequency estimations, i.e., coarse and fine estimations. Its performance is evaluated by computer simulation with the application to a differentially encoded QPSK/differential-detection system. The proposed scheme shows its excellent characteristic, extending the frequency acquisition range to even that comparable to or larger than the symbol rate. Furthermore, it can track well a time variation of frequency offset
Keywords :
AWGN channels; Kalman filters; automatic frequency control; differential detection; filtering theory; frequency estimation; mobile satellite communication; modulation coding; personal communication networks; quadrature phase shift keying; radio receivers; tracking filters; AWGN channel; LEO satellite communications; automatic frequency control; coarse estimation; computer simulation; differentially encoded QPSK/differential-detection system; direct conversion-type receiver; fine estimation; frequency acquisition range; frequency estimation; frequency offset; global seamless personal communications; low Earth orbit; performance evaluation; symbol rate; time variation; two-step Kalman-filter-based AFC; Application software; Automatic frequency control; Communication system control; Computer simulation; Control systems; Frequency conversion; Frequency estimation; Low earth orbit satellites; Quadrature phase shift keying; Satellite communication;
Journal_Title :
Vehicular Technology, IEEE Transactions on
