Cognitive radio networks Wireless communication systems 5 Game theory 2 Mathematics 2 Radio frequency allocation 2 Ad hoc networks (Computer networks) 1 Antenna arrays 1 Computer network protocols 1 Computer networks 1 Frequency spectra 1 Low noise amplifiers 1 Machine learning 1 Power electronics 1 Radio 1 Receivers and reception 1 Remote sensing 1 Signal processing 1 Ultra-wideband devices 1 Vehicular ad hoc networks (Computer networks) 1