A Joint PHY-MAC Spectrum Sensing Algorithm Exploiting Sequential Detection

Spectrum sensing is one of the key functionalities in cognitive radios which enables opportunistic spectrum access. In a cognitive radio system, secondary users need to detect the emergence of primary users as soon as possible to avoid harmful interference. In particular, sensing performance can be evaluated by detection delay and sensing overhead. Sequential detection techniques such as quickest detection can achieve minimum detection delay, while MAC layer sensing scheduling of periodic energy detection has demonstrated its high sensing efficiency. These motivate us to propose a joint PHY-MAC spectrum sensing algorithm in this letter, which employs sequential probability ratio test in the PHY layer and a probability-based sensing scheduling mechanism in the MAC layer. This algorithm can minimize detection delay with limited sensing overhead. Simulation results reveal that it has remarkable performance improvement compared with periodic energy detection.