Frequency-Hopped Single-Sideband Modulation for Mobile Radio

Abstract

A frequency hopped single‐sideband (ssb) modulation with pilot tone (fh‐ssb‐pt) transmission scheme is described for mobile radio. The single‐sideband signal changes its carrier frequency every ẗ seconds, and the sequence of carrier frequencies is controlled by a suitable scrambling code. Co‐channel cells using the same frequency band in the mobile radio system use different scrambling codes with the result that co‐channel interference is altered from cross‐talk to random noise if ẗ is small. In the presence of Rayleigh fading, frequency hopping improves reception for stationary vehicles, and does not degrade the performance for moving vehicles. Further, the technique of frequency hopping may offer communications privacy. Expressions for s/n are derived for ssb, ssb plus pilot tone, and fh‐ssb‐pt in the presence of Rayleigh fading. Co‐channel interference effects are also considered.