Robust Localization with Unknown Transmission Power for Cognitive Radio

The transmission power and position of the primary user in cognitive radio (CR) is very precious information because information of the primary user determines the spatial resource. This opportunistic spatial resource is available for secondary users to exploit it. To find the position of the primary user, we try to use existing positioning or localization schemes based on ranging techniques but those require the primary user´s transmission power. Since most primary users in CR are legacy systems, there are no beacon protocols to advertise useful information such as transmission power. Some of the existing localization schemes do not require transmission power, but they do not work in Outer case that the primary user is out of convex hull of secondary user´s coordinates. We propose constrained optimization method to estimate transmission power and position without prior information of transmission power. As a result, simulations on two major cases of network deployment. It is proved that the proposed constrained optimization method increases the performance in mean squared error (MSE) between the true and the estimated values of transmission power and which position.