Trilateral Tradeoff of Sensing, Transmission, and Contention Times in a Multiuser Split-Phase CR Networks

One of the key studies in the cognitive radio networks is maximizing some important metrics such as transmission/energy efficiencies or throughput with respect to network parameters such as sensing and transmission time. There is always a tradeoff between sensing time and transmission time. While longer sensing times results in higher detection accuracy, it loses transmission opportunities and hence decreases transmission efficiency. Many works have been done to find the best transmission and sensing time to maximize the efficiencies such as transmission and energy, but the interference and hence the probability of collision was not defined and formulated correctly. In this paper, we consider the trilateral tradeoff between sensing, transmission, and contention times. To do this, the interference between primary user (PU) and secondary user (SU) is formulated. We consider interference due to both imperfect sensing and PU-return. Furthermore, the interference among SUs has been also formulated. These metrics are used in defining transmission efficiency and probability of collision as a constraint.