Frequency Band Sharing between Satellite and Terrestrial Fixed Links in the Ka Band

Broadband access by satellite in the Ka band is currently constrained by spectrum availability. Cognitive radio has emerged as a promising paradigm to improve the spectrum usage efficiency and cope with spectrum scarcity problems through dynamically detecting and re-allocating white spaces in licensed (incumbent) radio band to unlicensed (cognitive) users. In this context, the EU FP7 project CoRaSat is examining the possible ways in which improved frequency utilization could be possible in the Ka band via the use of cognitive mechanisms. Utilising spectrum scenarios between Fixed Satellite Services (FSS), Fixed Services (FS) and Broadcast Satellite Service (BSS) feeder links are studied and investigated, where FS links/BSS feeder links and FSS satellite downlinks play a role as incumbent and cognitive system, respectively. This paper examines the potential increase of spectrum utilisation of Ka band FSS/BSS and FS in an aim to increase the overall utilisation of the spectrum. Analytical results of database statistics are provided to support interference evaluations for determination of regions for potential spectrum utilisation improvements. Cognitive zones based on the free space propagation model and full ITU P452-15 model are both determined and compared to highlight the importance of diffraction effects. In addition, operational aspects of the proposed techniques are also discussed.