Location Privacy of Non-Stationary Incumbent Systems in Spectrum Sharing

Although using geolocation databases for spectrum sharing has many pragmatic advantages, it also raises potentially serious operational security (OPSEC) issues. OPSEC is especially a paramount consideration in the light of recent calls in the U.S. for spectrum sharing between federal government (including military) systems and non- government systems (e.g., cellular service providers). In this paper, we explore the OPSEC, location privacy in particular, of incumbent radars in the 3.5 GHz band. First, we show that adversarial secondary users can easily infer the locations of incumbent radars by making seemingly innocuous queries to the database. Then, we propose several obfuscation techniques that can be implemented by the database for countering the inference attacks. We also investigate the inherent tradeoff between the degree of obfuscation and spectrum utilization efficiency. Finally, we validate our discussions by providing results from extensive simulations.