General scheme for always transmit solution in cognitive radio systems

Abstract

Cognitive radio is a promising technology that uses radio spectrum opportunistically and efficiently. In this paper, we propose a general scheme for enhancing the cognitive sources of data transmission to provide "Always Transmit" solution using mixed strategies in cognitive radio context. Indeed, we propose to combine underlay and interweave approaches depending on the activity of the primary system. We analyze the Ergodic Capacity of cognitive transmission under joint transmit power constraint and interference power constraint over Nakagami fading channels. We show the gain of our approach versus other approaches in literature. This framework accounts for most of the parameters that affect the performance and provides fundamental insights that may be of value to the transmission scenario, such as the spectrum sensing duration, spectrum hole detection, primary system bandwidth occupancy, transmit and interference power constraints, and fading.