On the duality of Phase-based and Phase-less RSSI MUSIC algorithm for Direction of Arrival estimation

In last years the interest in indoor localization techniques is grown very quickly: due to huge increase of interest in domotic technologies and to fast improvement of capabilities for mobile devices, which are becoming always-connected support points for standard users, the capability of making spatial data-contextualization has become an important point of interest. Existing GPS technologies aren’t capable of realizing sufficient accuracy needed for indoor positioning, so it is necessary to find alternative cost-effective methods to resolve localization problem. Excluding odometry-based tracking methods (which present a lot of uncertainty for making an absolute positioning), famous signal DoA (Direction Of Arrival) spectral-based localization algorithms like CAPON, ESPRIT, MUSIC[1],[2] provide valid localization accuracy assuming device capability to analyze in real-time physical parameters (amplitude/phase) of received radiocommunication signals to a spatial antenna array. This requirement could be achieved using ad-hoc radio equipment, which causes an increase of production costs: maybe, it is far better to develop some kind of new algorithms capable of using standard IEEE wireless protocols information (like RSS indicator, RSSI) for positioning elaboration. In this article, it will be analytically demonstrated the capability of MUSIC[1] algorithm to elaborate RSSI standard transceiver values (placing some measurement conditions), and there will be shown a comparison between DoA localizations using the classical information set (amplitude/phase) and the RSSI set (obtained simply reading transceiver standard registers). Key–Words: indoor positioning, indoor localization, DoA, RSSI, wireless, MUSIC, tracking, mobile devices