Temporal synchronization of frequency hopped DPSK
Abstract
The downlink temporal synchronization strategies for a frequency hopped differentially encoded phase shift keying (FH/DPSK) signal are examined. Arguments are presented to support the concept of a burst distribution of sync hops, or 13-bit encoded hops used only for synchronization. The burst distribution is shown to provide a favorable tradeoff between input signal-to-noise ratio and probability of a false alarm. The synchronization process, which includes acquisition, verification, and track modes is reviewed. Envelope detection of the dehopped signal is used to provide an indication of initial acquisition as well as a coarse timing estimate of the sync hop time-of-arrival. The sync hop is also quadrature detected to verify the presence of the sync hop and to provide a fine timing estimate accurate to within a small fraction of a data bit. Simulations of the coarse and fine root mean square timing estimate error are shown to approach the theoretical lower bounds.
- Publication:
-
Electrical and Computer Engineering, Volumes 1 and 2 4 p (SEE N93-30215 11-31)
- Pub Date:
- 1990
- Bibcode:
- 1990ecev.confV....S
- Keywords:
-
- Frequency Hopping;
- Phase Shift Keying;
- Satellite Communication;
- Synchronism;
- Temporal Distribution;
- Downlinking;
- Time Measurement;
- Communications and Radar