Cognitive radio (CR) technology is being applied to many different communications systems. By providing the ability of spectrum sharing, CR technology allows for improved commercial data services, and allowing for new unlicensed services to operate in pre-allocated bands in an opportunistic manner as secondary users.the study the possibility of increasing the utilization of the TV band by allowing WiMax to share this band as a secondary user. TV band was chosen since it is known to be underutilized, making it a prime candidate for applying CR technology. In the study, employed Dynamic Spectrum Access (DSA) technique such that a secondary WiMax user continuously scans the TV band for temporarily unutilized channels, and dynamically use the available channels. That improved the utilization of TV Band.