Digital Transmission Capabilities of a Transportable Troposcatter System

The digital transmission performance of a transportable troposcatter station is evaluated as a function of path length. Equipment parameters are chosen to be representative of a compact full-scale terminal capable of serving a major switching facility. While error rate evaluations for troposcatter transmission have been made previously, they have generally corresponded to the conditions of specific systems. Here, a reasonable path model and set of transmission parameters, thought to be representative of practical situations, have been chosen to allow performance evaluations to be made over the full gamut of range, propagation frequency, and bit rate conditions that are of interest. The two modes of digital transmission considered are direct-carrier modulation and subcarrier modulation within an FDM-FM baseband. The error-rate estimates finally determined reflect error contributions from all causes, with enhancement achieved from diversity operation.