Preserving Incumbent Users' Privacy in Server-Driven Dynamic Spectrum Access Systems

Dynamic spectrum access (DSA) technique has emerged as a fundamental approach in improving spectrum utilization to mitigate the spectrum scarcity problem. As a key form of DSA, government is proposing to release more federal spectrum for sharing with commercial wireless users. However, the flourish of federal-commercial sharing hinges upon how federal privacy issues are managed. In current DSA proposals, the sensitive operation information of federal incumbent users (IUs) needs to be shared with a dynamic spectrum access system (SAS) to realize spectrum allocation. However, SAS is not necessarily trust-worthy for holding such sensitive IU data, especially considering that FCC allows some industry third parties (e.g., Google) to operate SAS for better efficiency and scalability. Therefore, the current proposals dissatisfy the IUs' privacy requirement. To address the privacy issues, this paper presents an IU-privacy-preserving SAS (IP-SAS) design, which realizes the spectrum allocation process through secure computation over ciphertext based on homomorphic encryption so that none of the IU operation information is exposed to SAS.