Radio Resource Tomography of Cognitive Radio Networks

Cognitive radio (CR) is promising toward future wireless communication. By incorporating co-existing primary system(s) and CRs into a cognitive radio network (CRN), it is possible to significantly enhance overall spectrum efficiency, provided that CRs can precisely explore appropriate spectrum and network activities, which we call CRN tomography by borrowing the terminology from medical imaging. CRN tomography can actively or passively measure or infer CRN parameters and traffic patterns. Conventional CR spectrum sensing to find the spectrum holes falls into a simplified scenario of passive CRN tomography. Like medical tomography, we propose active CRN tomography by a realistic probing signal with cooperative adaptive modulation and coding (AMC) according to SINR. We successfully demonstrate that the active radio resource tomography can support real-time adaptation to dynamic environments without any a priori information from radio channels.