  Development of smart spectrum sensing techniques is the most important task
in the design of a cognitive radio system which uses the available spectrum
efficiently. The adaptive SNR estimation based energy detection technique has
the dual benefit of improving the efficiency of spectrum usage by capitalizing
on the underutilization of the spectrum in an adaptive and iterative fashion,
as well as reducing the hardware resources leading to easy implementation on a
versatile and diverse group of cognitive radio infrastructures. The use of
adaptive threshold for energy detection based on SNR estimation improves the
spectrum sensing performance and efficiency of the cognitive radio by many
folds, especially in low SNR as well as high noise variance situations. The
proposed method is implemented on the USRP B200 and results show significant
improvement in the detection rate of primary users as compared to conventional
energy detection techniques.
