As far as the Interfering Transmitter (ILT) - Victim Receiver (VLR) path is concerned, mutual angles and subsequent antenna discrimination angles/azimuths in horizontal plane are pre-determined by calculations already performed in the relative azimuths / elevation on the victim (VLT-VLR) and interferer (ILT-ILR) paths and with the setting of the relative positioning of the VLR with ILT.
At the same time, the vertical angles (tilt) of the antennas in the elevation plane are similarly assumed to be pre-determined during the antenna gain calculations for VLT-VLR and ILT-ILR paths.
For all angle calculations, the azimuth reference is the ILT-VLR path and the elevation reference is the horizontal plane.