satelite

Modulation and Coding to Improve Power and Bandwidth Efficiency of Small Earth Stations
Abstract

The objective of this project is to maximise the power and bandwidth efficiency of small satellite earth communication terminals whose main limitation to satellite capacity is a non linear transmitting power amplifier. A form of envelope equalisation is presented in which regular QPSK modulation is used together with instantaneous data magnitude modulation so as to produce a near constant envelope signal when filtered with root 35% raised cosine filtering. The algorithm for deriving the magnitude values is presented along with results using a data look-up table approximation. Bit error rate figures are presented for envelope equalisation combined with a (4096,3249) binary product code and MAP decoding. It is shown that at 10-6 BER the is 3.52 dB some 0.26 dB from the linear system. The results are compared to the Shannon bound for code performance obtained by solving recursively S...