Differentially coherent code phase synchronization technique in a DS-SS mobile packet radio

In the direct sequence spread spectrum packet radio system, pseudonoise (PN) code synchronization is an essential part which could affect the overall system performance and has to be done in a short time period. In this paper a code phase synchronization device which employs differential detection structure to enhance the overall packet detectability is presented. This device also employs the automatic threshold adaptation technique which was previously presented as a practical scheme to be applied for packet radio communication. However this method called ATC is not suitable for the fading environment which is common in mobile communication. By employing the differential detection structure as its signal preprocessor, the proposed device can still exploit the advantage of ATC and gives significant improvement in terms of packet loss probability in the fast Rayleigh fading channel.