Impact of sensing errors on the queueing delay and transmit power in cognitive radio access

Abstract

We study a multiple-access system with a primary user (PU) and a secondary user (SU) utilizing the same frequency band and communicating with a common receiver. Both users transmit with a fixed transmission rate by employing a channel inversion power control scheme. The SU transmits with a certain probability that depends on the sensing outcome, its queue length and whether it has a new packet arrival. We consider the case of erroneous sensing. The goal of the SU is to find the optimal transmission scheduling policy so as to minimize its queueing delay under constraints on its average transmit power and the maximum tolerable primary outage probability caused by miss-detection. The access probabilities are obtained efficiently using linear programming.