Performance characterization of a long over-water digital microwave link

The observed performance of a long, over-water microwave link between Swingate, England, and Houtem, Belgium, is described. To combat anomalous propagation as well as multipath, adaptive equalization and higher-order diversity have been employed with a 4-GHz digital radio. Performance data were collected over a 12-month period (Aug. 91 - Jul. 92) to allow characterization of both error statistics and fading statistics. The objective of the test was to characterize and compare the performance of second-, fourth-, and eighth-order diversity, and to compare the performance of DS-0, DS-1, DS-2, and DS-3 data rates. These comparisons were all done simultaneously by using several bit-error rate test sets and analog recording instruments. Results indicate modest performance improvement with increasing order of diversity, general agreement with performance prediction models for line-of-sight radio, general agreement with models used to extrapolate lower bit rate (e.g., DS-0) performance from mission bit rate (e.g., DS-3) performance, and general agreement with CCITT and CCIR performance objectives