A prediction method for angle diversity improvement on digital radio links

Angle diversity is a rather new approach to counteract multipath fading at a substantially lower cost than space diversity: in fact a single dual beam antenna or two close antennas require fewer tower modifications. The author presents a method based on the two rays multipath propagation model formerly developed by Rummler (1979), and it has been derived from the well established performance prediction method for space and frequency diversity on digital radio links, developed in CSELT by Damosso (1985) and Damosso and Ordano (1989). The main features of the model are the capability to cope with different antenna pointing configurations (elevation and separation of the two beams) and the possibility to consider both angle and pattern diversity. As far as the signal combining is concerned, an ideal switching is applied to the two channels, derived directly from the antennas or processed in order to provide sum and difference radiation patterns