Database-Assisted Distributed and Cloud-Based Access Methods for Unlicensed and Radar Bands

This paper focuses on the design of methods which enable unlicensed devices to use the frequency spectrum already allocated to rotating radar systems without causing interference to those radars. We first present a database-assisted spectrum sharing/co-existence mechanism for radar spectrum bands. This mechanism takes into account the real spectrum usage behavior of different radars, and is also implemented by prototyping a real-time rotating radar beam emulator, a radar spectrum database using MySQL software, and spectrum access algorithm on wireless open access research platform. Then we propose a cloud-based unified channel access (UCA) method and a distributed UCA method for co-existence of multiple competing users in unlicensed and rotating radar spectrum bands. We model the UCA problem as a game and propose iterative methods (i.e., algorithms) to obtain the solution of the game. We study the stability of the proposed methods under several different scenarios. We show that the proposed UCA game is a potential game, and also show that the proposed methods guarantee convergence to a Nash equilibrium. Our results show that the cloud-based method allows fast convergence and can achieve performance that is close to optimal solution.