Radio frequency identification (RFID) is a proven automation
technology finding application in various commercial sectors. These
applications involve locating all tagged items automatically using
available RFID readers. RFID readers are of two types, fixed and
mobile. The number of readers required to cover an area depends on
factors such as the properties of the reader, tag and the shape of
the area to be covered. This paper presents an algorithm to find
the minimum number of fixed RFID readers required for complete
coverage of an area of irregular shape. This approach, which
applies the Graham's scan algorithm of computational geometry, can
be used for buildings, warehouses, etc., of any shape. The
algorithm determines the required number of readers by considering
the interrogation range of the reader. A methodology of forming the
convex hull/polygon covering the irregular area, and subsequently
placing the readers at specified locations within the polygon based
on the properties of the reader is discussed here. A sample tiling
of an irregularly shaped floor space is shown as an example, and
applications of the tiling algorithm are indicated by giving verbal
sketches of automation systems for a food court, a parking lot, and
an airport baggage tracking system that can make use of it.