Location Verification Systems Based on Received Signal Strength With Unknown Transmit Power

In the context of location verification systems (LVSs), this letter proves that the knowledge of a legitimate user's transmit power has no effect on the optimal performance of a received signal strength (RSS)-based LVS. Specifically, we prove that the detection performance of a generalized likelihood ratio test (GLRT), where the unknown transmit power is estimated, is identical to that of a differential likelihood ratio test (D-LRT). Our analysis also proves the asymptotic optimality of D-LRT for an RSS-based LVS with unknown transmit power. These results are important for real-world deployments of LVSs, since D-LRT incurs a significantly lower implementation cost relative to GLRT.