QoS of cognitive and primary networks and spectrum sensing tradeoff using always transmit strategy over Nakagami-m fading channels

Cognitive radio is widely expected to be one of the next generation in wireless communication which uses radio spectrum opportunistically and efficiently. In this paper, we present the performance of “Always transmit” strategy for the Quality of Service (QoS) management for cognitive and primary system. We study the tradeoff between spectrum sensing duration and the QoS at cognitive network and the QoS must be guaranteed at primary network. We derive the closed-form expressions of the outage probability over independent but not necessarily identically distributed Nakagami-m fading channels. Computer simulation results are presented to show that the spectrum sensing duration affect (resp. not very affect) the performance of cognitive system under strict (resp. relaxed) constraint limit at primary system, and that the strategy “Always transmit” outperforms others conventual cognitive radio strategies.