Radio Frequency Identification (RFID) Application to 3-Dimensional Localization and Full Coverage

This dissertation pursues RFID support for localization and efficient full coverage of given 3-dimensional (3-D) space, aiming to guarantee for pinpointing an object (i.e., a reader) in a 3-D space. We apply the localization approaches to pinpoint an object inside the 3-D full coverage space. The localization approach considers the very first range-free 3-D localization using only RFID tags without other devices or sensors. Therefore, it avoids the need for distance estimation according to received wireless signal strength (known to be notoriously inaccurate) or phase difference (being complicated). Given a number of RFID tags deployed as reference nodes at known locations in a hexahedron (like a shipping container or a storage room), an active localization scheme iteratively determining a 3-D sphere best covering the activated reference tags, referred to as the Decision Boundary optimization scheme (DeB), is considered. The DeB scheme is contrasted with a prior technique based on a Nelder-Mead nonlinear optimization (NeM). We have carried out simulations and testbed experiments to evaluate the proposed schemes. DeB is shown to achieve the localization error as small as 0.07 ft and is more flexible in placing reference tags. If the object is located close to a side or corner of a 3-D space, enhanced DeB (EDeB) can improve localization accuracy dramatically. For efficient localization, we apply the RFID placement with full and K-coverage system. Based on the actual radiation pattern of reader antennae obtained from empirical measures and following 6th order polynomial regression, we have arrived at more realistic antenna coverage deemed to be balloon-shaped. The coverage of interest is then modeled by rectangular frustums inscribed in the balloon shape dictated by the antenna, enabling determination of the best rectangular frustum (BRF) for a given 3-D cuboid. As RFID reader antenna placement in 3-D is NP-complete in general, an efficient heuristic algorithm is proposed to pack BRFs in the 3-D cuboid with full coverage and as few antennae as possible. Numerical evaluation and testbed experiments are carried out to evaluate the proposed antenna placement algorithm.