A NOVEL WAVELET PACKET BASED DIRECTION OF ARRIVAL ESTIMATION FOR SPECTRUM SENSING IN COGNITIVE RADIO NETWORKS

Spectrum Sensing is the quintessence of Cognitive Radio Network and helps in decongesting the RF band. A lot of research has already been done in detection of free space in the frequency spectrum and the need of the hour is exploitation of a novel characteristic of a signal from a newer perspective. Cognitive radio works in a multi-antenna based system with a number of secondary user sensors wherein the signals from primary user is received from different directions. Thus, the angle dimension of the received signal can also be exploited to propose new sensing schemes. In this paper, a novel technique based on direction of arrival estimation has been augmented with wavelet packet decomposition to enhance the performance characteristics in case of closely-spaced DOA and low SNR. The proposed algorithm provides high resolution as well as significantly reduced computation load. The better performance and reliability of the proposed WDOA estimation have been experimentally validated and presented in form of computer simulations.