Spectrum is a very precious resource and thus underutilization of a large part of allocated spectrum is not affordable. Where increasing demand for wireless applications has made it difficult to manage limited spectrum, allocated spectrum utilization is found to be very low. Cognitive radio is proposed as a promising solution for increasing spectrum utilization and thereby helping to mitigate s...

Dynamic spectrum access with cognitive radios has become a promising approach to improve spectrum efficiency by adaptively coordinating different users’ access according to spectrum dynamics. However, selfish users competing with each other for spectrum may exchange false private information or collude with others, in order to get more access to the spectrum and achieve higher profits. In this ...

Spectrum sharing, as an approach to significantly improve spectrum efficiency in the era of 6th generation mobile networks (6G), has attracted extensive attention. Radio Environment Map (REM) based low-complexity sharing is widely studied where occupancy measurement (SOM) vital construct REM. The SOM three-dimensional (3D) space becoming increasingly essential support with space-air-ground inte...