Sensing and power control in cognitive radio with location information

In a cognitive radio network, the secondary user (SU) will cause the primary user (PU) to be in outage when the SU miss-detects the PU and transmits with a power that prevents the PU receiver from decoding its data. Hence, the outage of the PU caused by the SU depends on the SU's transmission power and its probability of detection. For a given outage probability, it is possible for the SU to lower its transmission power in exchange for a lower probability of detection. The SU may not even require spectrum sensing to protect the PU if the SU's transmission power is low enough or when it is very far from the PU. In this paper, we first determine the distance of the SU from the PU such that the SU could use the channels without spectrum sensing. Then, at locations where the SU requires spectrum sensing, we determine the sensing parameters and the transmission power that will maximize the SU's throughput subject to an outage constraint for the PU.