| With the services provided by MSAT Satellites, conventional pagers can be implemented on a mobile terminal enabling users to receive paging messages in cars, trucks, boats and in remote areas. With a two-way messaging system, customers are able to not only receive but also send paging messages. However, this requires a burst demodulator at the Hub earth station. The goal of the research project is to design a group demodulator to receive, demodulate and decode return link, NCBFSK, burst paging signals, that are transmitted from the mobile end of the satellite link, with a message recovery rate of 98%. Since Fung has focused on the timing synchronization algorithm and the decoding process for the demodulator, this thesis will focus on the design of the frequency estimation algorithm for the demodulator with a burst, preamble-less, and short signal format and its integration into the simulated messaging system developed by Fung.;A single user and a multi-user frequency estimation algorithm are developed in this thesis which are mainly based on an operation on the Short Time-DFT, called the spectrogram. (Abstract shortened by UMI.)... |
