A FADE-COMPENSATION TECHNIQUE FOR DIGITAL LAND MOBILE SATELLITE SYSTEMS

This paper proposes a novel fade-compensation algorithm using a pilot symbol-aided technique for digital and mobile satellite systems. In a conventional pilot symbol-aided system, a pilot symbol from a known ps eudorandom-symbol sequence is inserted periodically into the data-symb ol sequence in the transmitter. At the receiver, these pilot symbols a re extracted from the received signal and used to estimate the signal distortion introduced in the fading channel. The resultant estimate is then used to correct the fading effects in the received data symbols. In this paper, a novel fade-compensation technique that uses both the pilot symbols and the data symbols is proposed. A series of computer- simulation tests has been carried out to assess the effectiveness of t he technique on the bit-error-rate (EER) performances of an uncoded 16 -ary phase-shift keyed (16PSK) and an uncoded 16-ary quadrature-amplit ude modulated (16QAM) signal over the land mobile satellite channels. The results have shown that substantial improvements in the EER perfor mances of the systems can be obtained, compared to those using only th e pilot symbols.