A new frequency synthesizer for coherent communication in frequency hopping spread spectrum multiple access communication systems

Abstract

Spread spectrum multiple access (SSMA) is a communication system where narrow-band information spectrum is spread uniformly over communication bandwidth and plural communication parties share the same frequency band at the same time. In frequency hopping SSMA (or FH-SSMA), PN signals for spectrum spreading of information signal are generated by a frequency synthesizer. Conventional frequency synthesizers cannot generate PN signals which have the same frequency and phase in the corresponding timeslot at the transmitter and receiver sides independently. For this reason, coherent detection is impossible. Although many frequency synthesizers using SAW filter have been proposed for the realization of coherent communication in a frequency hopping system, there are some problems, including errors in synthesized frequency and phase uncontrollability. This paper presents a new frequency synthesizer to realize coherent communication in FH-SSMA.