Abstract:
Cognitive radio technologies tackle spectrum scarcity issues in the bandwidth when the
number of users in the network begin to rise. Secondary users that access to the spectrum have
to sense beforehand to detect any free spectrum offered and upon opportunity of vacant
spectrums, gain access. During sensing, the network is prone to security attacks that are
commonly caused by malicious users which severely affect the throughput of the network. In
conventional spectrum access scheme, a fixed threshold is set that determines the transmitter
energy of incoming signal. In this thesis, the throughput is analyzed and enhanced during the
overlay mode of secondary user transmission, in the incidence of primary user emulation
attackers, all the while optimizing the threshold of sensing that reduces the total error
probability, that outperforms that of a conventional scheme that uses a fixed threshold.
