Digital Radio Link: Comparison of Two Modulation Forms with Respect to Frequency Selective Fading (Digital Radiolaenk: Jaemfoerelse Mellan tva Modulationsformer med Avseende pa Frekvensselektiv Faedning)

摘要

Two 4-phase modulation formats MSK respectively QPSK are compared with respect to the resistance to frequency selective fading caused by simulated multipath propagation. The multipath simulations at RF-level are based on a simplified 3-way model, which has shown to be relevant for Swedish conditions. The comparison of the different modulation techniques are presented in terms of a comprehensive summary, based on exhaustive simulations of multipath propagation in the time- and frequency-domain. The two modulation forms are primarily compared in terms of signature-analysis and critical regions, which characterizes the availability of the system during frequency selective fading.