Abstract—Over the past decade, Rapid growth in the field of wireless communication has increased demand for spectrum resources and created a shortage of available radio spectrum. The cognitive radio technology is one of the promising technology to address the scarcity of spectrum resources, from the introduction of cognitive technology there is a lot of research is going on its spectrum sensing techniques, this paper aimed to provide an in-depth review on recent advances in spectrum sensing techniques and thoroughly presents the merit, demerits, and scope of further research of each spectrum sensing techniques. Finally, this review paper is presented to help new researchers and to make them familiar with concepts of spectrum sensing.