Coexistence study of opportunistic access network

TV Frequency band is under-utilized by current licensed systems according to the evaluation results from some European organizations. Various studies on unoccupied white space have been performed both from the perspective of protection to licensed systems and from the perspective of achieving optimistic results for unlicensed systems. While considering the interference to cognitive radio systems (CRS) which use the white space in an unlicensed way, the amount of suitable white space may decrease. Based on the radio frequency (RF) ability of current standard, this paper evaluates the performance loss of CRS due to the interference from DTMB (Digital Television terrestrial Multimedia Broadcast) system which is a typical TV scheme developed by China. Meanwhile, both adjacent channel coexistence and second adjacent channel coexistence are taken into account to reveal the interference to CRS. Furthermore, this paper would like to draw more attention to the performance of CRS when using TV white space frequency.