摘要：The paper examines contemporary issues with cognitive radio networks as it relates to spectrum scarcity and the demand of users. With recent advancement in technology and increase in the need for wireless communication systems, this has given rise to search for desirable spectrum bands for transmission. Cognitive Radios renders an answer to the trouble by sensing the idle (licensed) bands and allowing (secondary) users to broadcast and transmit in these idle spaces. Spectrum sensing forms the main block of cognition cycle. However research has shown by previous researchers that radio spectrums are being under- utilized in most cases. This paper attempts to profound a solution to efficient and effective spectrum utilization has identified the current challenges and issues faced by spectrum sensing for cognitive networks. The principal issues with cognitive radios are that it should not interfere with the primary users and should vacate the band when it is required. For this sole reason, energy detector system model was used in this paper and performance evaluation was calculated. The performance evaluation is done for cooperative spectrum sensing schemes under non fading environment This paper provides a clear understanding of cognitive radio technology, and its role in national development. Then several challenges and security issues are discussed.
