CTA diffusion based recursive energy detection

Cognitive radio (CR) has been seen as a promising technology to make radio spectrum usage more effective by providing an opportunistic access for secondary users to the licensed spectrum areas. CR systems need to detect the presence of a primary user (PU) signal by continuously sensing the spectrum area of interest. Radiowave propagation effects like fading and shadowing often complicate the detection of PU because the PU signal can be weak in a particular area. By sensing the radio spectrum area of interest in a cooperative manner, the detection performance of PU signals can be increased and made more robust to channel fading. This paper studies distributed spectrum sensing in a cognitive radio context. We propose and analyse a distributed, combine and adapt type (CTA) of diffusion energy detection scheme where a central data processing unit is not needed and the required test statistics is estimated across the network. CR nodes fuse the power estimates of several neighbour nodes in the network. The PU signal is assumed to be in slow fading. The theoretical findings are verified through simulations. The proposed CTA algorithm is compared with the ring around distributed power estimation algorithm. Key–Words: Cognitive radio, distributed estimation, distributed detection, adaptive networks, energy detection.