Spectrum Monitoring Based on Error Vector Magnitude and Received Signal Strength Indicator

Abstract

Wireless communication systems may suffer from interferences caused by other emitters. Modern research and development on these systems is focusing on a more dynamic spectrum usage in order to mitigate or avoid such interferences. Nevertheless, this adaptability requires detecting them by either spectrum sensing or spectrum monitoring. While spectrum sensing observes the electromagnetic spectrum regarding the presence of signals, spectrum monitoring exploits the reception metrics during a communication for detecting interferences. This paper proposes a spectrum-monitoring algorithm that is making use of the error vector magnitude of the received signals. As a high error vector magnitude may indicate both an interference and a low signal power, the received signal strength indicator is used to distinguish these cases. The primary user presence is identified based on linear classification by the help of support-vector machines, which take the error vector magnitude, the received signal strength indicator, and the modulation order as input. The success of the spectrum-monitoring algorithm is demonstrated based on simulations of quadrature amplitude modulated signals.