A unified analysis of multipath degradation in multilevel modulation radio systems

In microwave digital radio transmission, waveform distortion due to frequency selective fading becomes a dominant factor of degradation. To evaluate the degradation of different systems in a unified way, the waveform factor is defined first. With the aid of the concept 'waveform factor', the eye aperture is easily obtained. The waveform factors are evaluated for various modulation schemes. Next, on the basis of the relation between propagation parameters and waveform factor in two-ray fading, the estimation formula of the outage probability for various digital radio systems in line-of-sight propagation is derived. The proposed factor is determined uniquely by system parameters, such as modulation scheme, system impulse response, and symbol rate. With the aid of this factor, digital radio system performance during multipath fading is easily evaluated.