الفهرس 
Cognitive Radio HistoryOnly 14 pages are availabe for public view
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Abstract
The fast development of bandwidth requesting wireless technologies has led to the problem of spectrum shortage. However, studies present that licensed spectrum is underutilized. Cognitive radio technology pledges a solution to the problem by permitting unlicensed users, opportunistically access to the licensed bands. Spectrum sensing is a prime component of the cognitive radio technology. A large number of sensing techniques have been produced to sense the existence or not of a licensed user.
This thesis assess the performance of the energy detection based spectrum sensing technique in fading and noisy mediums. The performance of the energy detection technique was evaluated by using Receiver Operating characteristics (ROC) curves over additive white Gaussian noise (AWGN) and fading (Rayleigh) channels.
The experiments are carried out using USRPN210 and GNU radio that help the reader to understand the concept of underutilized frequency band and its importance in Cognitive Radios.
A new threshold estimation technique for the spectrum sensing (SS) using stochastic approach for energy detection (ED) has been presented. The performance of stochastic threshold estimation approach under noise uncertainty environment has been tested. Under noise uncertainty and obeying the 802.22 standard, the stochastic threshold has achieved comparable results and even outperform the double threshold in a low signal to noise ratio (SNR).