Experimental investigations of data transmission impairments of QPR digital radio systems

Computer-controlled setups were used to investigate the characteristics of data transmission impairments of 9QPR digital radio systems in real time. The observed impairments can be categorized into normal and anomalous impairments according to recorded signal levels. The anomalous impairments, which are observed at lightly faded power levels, are caused by radio propagation anomalies, hardware instabilities, or their combination. They often manifest themselves as error bursts lasting a few milliseconds. Although well-designed antenna systems could reduce the rate of occurrence of anomalous impairments of digital radio systems caused by radio propagation, innovative antennae designs have to be complemented with fast signal processing techniques if anomalous impairments of all types are to be prevented