Reliability improvement for an RFID-based psychiatric patient localization system

Collaboration between Field Generators, Readers and Tags generates the required functions in using radio frequency identification (RFID) for psychiatric patient localization. The Field Generator continually transmits trigger signals within its transmission range. When a Tag, which a patient wears, receives a trigger signal from a Field Generator, the Tag responds to a Reader with its own ID and ID of the Field Generator that issues the trigger. Based on Field Generator IDs that a Tag responds to, the location of the patient wearing the Tag can be estimated approximately. However, in recent RFID based localization systems, certain phenomena impact the reliability of signal transmission and decrease the feasibility of the localization system. To eliminate interference from different Field Generators, this study presents a novel graph coloring with merging and deletion (GCMD) algorithm for such a localization system that eliminates interference from Field Generators located near each other. Experimental results indicate that the GCMD algorithm significantly improves localization system reliability, thereby increasing the feasibility of RFID for psychiatric patient localization. (C) 2008 Elsevier B.V. All rights reserved.