Preamble-less demodulator for Inmarsat standard-C coast earth station

The authors propose a new preambleless demodulator method for mobile satellite communications systems. It was realized by a switch-back method with real-time processing carrier recovery to track carrier variations caused by multipath fading and carrier frequency changes. The ACE-DEMO concept, which is carrier recovery using an adaptive filtering technique, was employed because of its wide pull-in frequency range. A preambleless demodulator for the Inmarsat standard-C signaling channel using the proposed method was developed. In the performance evaluation, the first generation preambleless demodulator satisfied the 2.2% burst error probability for the 4.7-dB E_b/N₀, 7-dB carrier-power-to-multipath-power ratio multipath fading, and 65-Hz/s carrier frequency change environments to satisfy the Inmarsat standard-C specification