Abstract: Cognitive radio is a new promising technology that aims to alleviate the spectrum scarcity problem in wireless communications by allowing access of unlicensed (secondary) users to frequency bands that are allocated to licensed (primary) users, in a way that does not affect the quality of service (QoS) of the licensed networks [1], [2].In this paper we propose to enhance the sensing-throughput tradeoff in opportunistic spectrum access cognitive radio networks by performing spectrum sensing and data transmission at the same time. We also compare the average achievable throughput of the proposed cognitive radio system with the respective throughput of the conventional opportunistic spectrum access cognitive radio system in [12]. Finally it is shown that the proposed cognitive radio system exhibits improved throughput under a single high target detection probability constraint imposed for the protection of the primary users.

Keywords: Cognitive radio, opportunistic spectrum access, optimal power allocation, spectrum sensing, throughput maximization.