Cross-Polarisation Discrimination (XPD) Model for 30 GHz (VP/HP) Radio Signals due to Rain for Indian Tropical Climate

Abstract

The performance of terrestrial or space to earth communication system operating above 10 GHz is severely degraded due to the presence of rain drop size and its distribution in the tropical climate. In mm wave frequencies, rain attenuation and cross polarisation of radio signals becomes major limiting factors for the performance of communication system. This has generated interest in the studies of rain induced attenuation and depoplarisation for terrestrial or space to earth path communication and development of reliable and accurate prediction models required for the system design. Depolarisation of radio signals due to rain drop size distribution can cause interference or cross talk in radio signals, where polarisation is used to provide isolation between vertical and horizontal polarised radio signals as in the case of frequency reuse. In this paper, Cross Polarisation Discrimination (XPD) models have been developed based on co-polar and cross –polar attenuation at 30 GHz vertical and horizonal polarised radio signals during rain events using rain attenuation data measurement of 5 Km- line of sight (LOS) link at Dehradun, India. The variation of XPD with co-polar attenuation and rain rate have been described for vertical and horizontal polarised transmitted radio signals at 30 GHz.