LARGE DOPPLER FREQUENCY COMPENSATION TECHNIQUE FOR TERRESTRIAL AND LEO SATELLITE DUAL-MODE DS CDMA TERMINALS/

This paper proposes a novel Doppler frequency shift compensation techn ique to achieve terrestrial and low earth orbit (LEO) satellite dual m ode DS/CDMA terminals robust to high Doppler shift and multipath fadin g. In order to satisfy the requirements of wide dynamic range and high accuracy simultaneously, the proposed scheme employs two state compen sation scheme, i.e., coarse compensation to keep dynamic range of abou t 100 kHz and fine compensation to satisfy its resolution of about 30 Hz, using block demodulation technique. Computer simulation results sh ow that the proposed scheme can sufficiently compensate for the offset frequency up to the range of about 100 kHz at the terrestrial and LEO satellite combined mobile communication systems.