Bounds and Tradeoffs for Cooperative DoA-Only Localization of Primary Users

Direction-of-arrival (DoA)-based localization is a suitable approach for estimating the position of primary users in cognitive radio networks, as it does not require knowledge of transmission power or propagation channel. In this paper we consider a scenario where secondary users obtain DoA estimates by multiple antennas or virtual antenna arrays. We express the Cramer Rao bound of the localization error as a function of the problem geometry and of array-specific parameters. Then, we investigate how the bound scales with the number of sensors and the number of antennas per sensor, and we address the following question: is it better to have more sensors with fewer antennas, or fewer sensors with more antennas?