Installation guide

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Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
RFID Tag Considerations
Appendix C—Large Site Traffic Analysis, page 116 provides traffic information that provides an idea of
what to expect when a network design synchronization is performed in a large-scale, active environment.
In the large-scale test environment, the network design consists of a four floor building with 41 access
points, without any obstacles or coverage areas defined and no calibration models beyond the included
defaults. Although the network design for this facility is complex from an architectural standpoint, the
overall size of the design is still considerably smaller than that of a similar designs containing obstacle
walls, doors, coverage areas, and multiple calibration models.
RFID Tag Considerations
RFID Tag Technology
The RFID tag industry has witnessed phenomenal growth since the announcement of several key RFID
mandates by large domestic retailers, the U.S. Department of Defense, and European retailers such as
Metro AG and Tesco. The most well-known of these was the announcement from WalMart in June of
2003 that would require their top 100 suppliers to include case and pallet-level RFID tags for shipments
entering a WalMart distribution center or store. Soon afterward, this was followed by an equally
momentous announcement from the Department of Defense detailing the future requirements for RFID
usage from all 40,000 DoD suppliers. These and other such announcements from well-known companies
such as Target Corporation, Best Buy, Circuit City, Sears, Albertsons, and Kroger catapulted the
previously-unnoticed RFID industry to unprecedented popularity in the eyes of Wall Street, the press,
and other industry observers.
The majority of RFID tags produced today are passive RFID tags, comprised basically of a microcircuit
and an antenna. They are referred to as passive tags because the only time in which they are actively
communicating is when they are within the RF field of a passive RFID tag reader or interrogator.
Another type of common RFID tag in the marketplace today is known as the active RFID tag, which
usually contains a battery that directly powers RF communication. This onboard power source allows an
active RFID tag to transmit information about itself at great range, either by constantly beaconing this
information to a RFID tag reader or by transmitting only when it is prompted to do so. Active tags are
usually larger in size and can contain substantially more information (because of higher amounts of
memory) than do pure passive tag designs. The tables shown in Figure 55 provide a quick reference of
common comparisons between active and passive RFID tags.