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EPC-compliant RFID UHF tags deliver accurate, affordable and unique identification. They create real-time visibility for identifying and tracking objects moving through the supply chain or on and off the shelves. But there are many different types of tags and formats to choose from, depending on the application.

By Vivek Khandelwal, Vice President of Marketing and Business Development, Verayo

Various technologies have been utilized in developing the RTLS available today. These underlying technologies — like ZigBee, Wi-Fi, infrared, ultrasound, ultra-wideband and other radio frequency systems — each impact the suitability of an RTLS in different ways. More important than just looking at the type of tag is evaluating how these technologies are implemented — as this will have significant impact on system performance, location accuracy, cost and reliability.

The asset tag is only part of the equation in achieving cost-effective, accurate data capture for an RTLS system. Each RTLS must also be reviewed within the context of the desired positioning application and the environment where it will be installed. All RTLS are made up of certain components. The most visible component is the asset tag itself. Tags can be tailored for mobile equipment, personnel, hospital patients, etc. In some cases, the functionality within the tag DOES play a crucial role in driving value. For example, San Diego, CA-based Awarepoint offers a hermetically sealed tag that withstands the harsh environment of steam autoclave sterilization up to 135 ºC, as well as immersion in the most common liquid sterilization methods used in hospitals. Not only must the tag withstand this harsh environment, it must be able to capture utilization information, cycle counts, etc. to drive value within a hospital surgical department. In this case, the tag is tailored to the need.

When selecting RTLS, vendor technology platforms must be evaluated on design trade-offs that balance cost and complexity with performance. In addition to understanding the tag functionality for the specific value a customer is driving towards, decision makers must look at these 5 critical success factors for long term success:

1. Enterprise-Wide Coverage. RTLS is at its best fully integrated into the fabric of the organization, maximizing user adoption and driving crucial applications (asset management, patient flow, throughput, etc.) that offer the maximum ROI.

2. Location Accuracy. In the healthcare environment, room level accuracy is a critical factor and must be obtained without a costly, disruptive and time-consuming infrastructure upgrade.

3. Installation & Maintenance. The cost and disruption of initial installation, ongoing calibration needs and potential for interference must be considered.

4. Interoperability. Standards-based technology and the ability to deliver data to end-users and third-party applications are crucial to fully leveraging the system.

5. An easily scaled installation that does not require a large capital purchase or long-term contractual commitment will deliver maximum ROI with minimum risk.

RFID is essentially a data container that provides an accurate and efficient way to transmit or store content. Content or data is stored and retrieved from an RFID tag electronically by RFID readers. RFID tags do not require a line-of-sight with the reader, and multiple tags can be read simultaneously. Additionally, RFIDs implementing a UHF interface can be read from distances of up to 20-30 feet from the reader.

The ability to store and retrieve content is only one aspect of a data container. Most applications want more than just easy and efficient access to the stored content; most want to ensure authenticity. Many RFID products, primarily in the High Frequency (HF) category, include mechanisms which ensure the authenticity of both data container and data.

Recently, a new class of "unclonable" RFID was introduced. These RFIDs are based on a silicon "biometric" technology, invented at MIT, called Physical Unclonable Functions (PUF). These RFIDs use a chip's unique and unclonable silicon fingerprint to enable very robust, yet low power consuming container authentication.

Content authentication is a well-understood issue. RFIDs should ideally store limited information, and this limited information should be encrypted using conventional cryptography. Such encrypted information would prevent any illegitimate entity to (mis-)use this information.

Until now, UHF RFIDs have been mostly targeting use cases that do not necessarily require security or authentication. Hence UHF products have been lacking some of the advanced security and authentication features found in HF products. But this could be easily addressed using a technology like PUF. A UHF tag with security and authentication features will provide customers with an ideal combination of accuracy, security and read range.


Wireless Design & Development