Abstract: Cognitive radio technology necessitates accurate and timely sensing
of primary users' activity on the chosen set of channels. The simplest
selection procedure is a simple random choice of channels to be sensed, but the
impact of sensing errors with respect to primary user activity or inactivity
differs considerably. In order to improve sensing accuracy and increase the
likelihood of finding channels which are free from primary user activity, the
selection procedure is modified by assigning different sensing probabilities to
active and inactive channels. The paper presents a probabilistic analysis of
this policy and investigates the range of values in which the modulation of
sensing probability is capable of maintaining an accurate view of the status of
the working channel set. We also present a modification of the probability
modulation algorithm that allows for even greater reduction of sensing error in
a limited range of the duty cycle of primary users' activity. Finally, we give
some guidelines as to the optimum application ranges for the original and
modified algorithm, respectively.
Keywords: Opportunistic spectrum access, cooperative spectrum sensing, wireless personal area networks