A comparison study of low bit rate DE-QPSK, TCM 8-ary PSK and 16-ary DE-QAM fully digital demodulators operating over a land mobile satellite link

1 January 1992

journal article
Published by Institution of Engineering and Technology (IET) in IEE Proceedings I Communications, Speech and Vision

Vol. 139 (3) , 319-328
https://doi.org/10.1049/ip-i-2.1992.0044

Abstract

In this paper, a complete structure of a fully digital low bit rate m-ary PSK and m-ary QAM demodulator, is given. Its architecture is optimised for applications in a land mobile satellite environment, where flat Rician fading, large Doppler shifts and low EJN0 are the main channel impairments. A power efficient 9.6 Kb/s differentially encoded (DE) QPSK and trellis coded modulated (TCM) 8-ary PSK as well as a bandwidth efficient 64 Kb/s DE 16-ary QAM fully digital demodulators are considered as application examples. All of them have similar architecture with the only difference being their decision units and the absence of fine AGC for the PSK schemes. We consider the digital implementation using digital signal processors (DSP) of virtually all demodulator operations. Their acquisition, steady state and tracking performances are evaluated by computer simulation over an AWGN and a Rician fading channel.

Keywords

This publication has 0 references indexed in Scilit: