Angle and space diversity: experimental comparison

Some results of a radio experiment performed to test the relative performance of antenna angle diversity (AAD) and vertical space diversity (VSD) on a line-of-sight microwave digital radio, using a 16 quadrature amplitude modulation (QAM) modulation scheme, are presented. Measurements have been made on a 60-km path in the north of Italy. In the experiment, a single dual-beam antenna was used and different angle diversity values have been tested. The results obtained suggest that the angle diversity receiving configuration gives protection comparable with space diversity in the presence of heavy selective multipath fadings; otherwise this protection is not as efficient as VSD. Nevertheless, the improvement offered by this technique is sufficient to consider its application to situations where space diversity cannot be used for tower loading or lack of space considerations