Design and Development of a Burst Acquisition System for Geosynchronous Satcom Channels

摘要

The key contribution of this work is to develop transmitter and receiveralgorithms in discrete-time for turbo- coded offset QPSK signals. The proposedsynchronization and detection techniques perform effectively at an SNR per bitclose to 1.5 dB, in the presence of a frequency offset as large as 30 % of thesymbol-rate and a clock offset of 25 ppm (parts per million). Due to the use ofup-sampling and matched filtering and a feedforward approach, the acquisitiontime for clock recovery is just equal to the length of the preamble. Thecarrier recovery algorithm does not exhibit any phase ambiguity, alleviatingthe need for differentially encoding the data at the transmitter. The proposedtechniques are well suited for discrete-time implementation.