The Convergence of Wi-Fi and RFID

Conversations about RFID are commonplace today. We’re constantly hearing about Wal-Mart and other retailer mandates, activities coming out of the Department of Defense, standards news from the likes of ISO and EPCglobal, and big technology players bringing new software and hardware solutions to the fore, designed to streamline supply chain operations and inventory management.

Perhaps lesser known to most, we’re also seeing another trend emerge — the convergence of active RFID and Wi-Fi. Unlike the systems mentioned above, active RFID involves tags with an energy source (batteries) that emit a signal to readers some distance away. The readers process the signal and determine the location of the tag, based on its presence in a particular zone or using triangulation techniques. To simplify, this kind of system provides an almost precise location of tags by coordinates within a particular physical space, very similar to GPS, but designed for use inside or in neighboring open spaces, such as parking lots or courtyards.

The Convergence

Active RFID technology has been available for years, using proprietary frequencies requiring their own equipment and infrastructure. But the convergence we’re seeing today, based on technology developed by AeroScout, Ekahau, Cisco and others, is based on active RFID systems that uses the same frequency as Wi-Fi networks, allowing end users to capitalize on existing infrastructure for wireless data networks. Not only does this reduce the overall implementation cost, but it also increases the advantages of location services for goods and people, and ultimately streamlines processes in a range of industries.

Going down a layer, companies can use RFID and Wi-Fi technology to learn more about their assets than simple physical location, such as entry and exit, shortage or overflow, out of flow, friend or foe, status and more. That data can then be processed and sent to business applications such as SAP, Oracle, Tibco, or i2 Technologies, or to generate notifications and alerts by e-mail, text message, PDA, etc. These “event processing platforms” have a high volume processing capacity for “location reports” that can reach up to several dozen million, with thousands of tags generating information every minute, every second, or even more frequently.

Market Opportunities

So, how can companies take advantage of RFID / Wi-Fi systems? Consider the following examples.

Retail / Supply Chain

Imagine if manufacturers of plasma TVs had real-time visibility into how their products move from retailer distribution centers to stores, and could find out when they leave the store, learning vital information such as the final price paid. Manufacturers would be able to use this information to improve demand chain planning, inventory management, and more, making sure that the right retailer has the right amount of product based on its needs.


In very complex manufacturing environments, such as aircraft manufacturing, Wi-Fi/RFID systems can offer line managers real-time visibility of work-in-progress (WIP), allowing greater control over the process itself, enabling more efficiency and consistency of assembly lines. Much of this process monitoring is done manually today, which is both costly and time-consuming.


Hospitals today have few systems in place to track and manage high-demand, high-cost assets. In fact, impossible as it may seem, most have no insight into the location or status of an IV Pump, and cannot tell you whether it is rented equipment or owned. Without this information, many hospitals rent and buy far more equipment than they truly need, assuming that the more they have, the easier it will be to find when needed. By tagging these assets with active RFID and using Wi-Fi networks to determine location, administrators can significantly reduce the financial burden and streamline the process of locating vital assets for better patient care.

Transportation / Logistics / Yard Management

How can yard managers monitor the status of a shipment of perishable goods that needs to be kept out of direct sunlight and at a specific temperature? What can an automotive manufacturer do to streamline the process of finding specific vehicles for shipping or maintenance among thousands in a facility? Or how about locating trailers full of goods once the truck has dropped the trailer for storage in a sea of others? Active RFID and Wi-Fi streamline and automate these manual time- and human capital-intensive processes.

Implementation Factors

Once you find a use for RFID in your enterprise — or a customer’s — then begins the actual implementation. When working with an end user on an active RFID and Wi-Fi implementation, it is important to think about and address the following considerations:


Tag prices for active RFID vary from $30–100 depending on volume, and will likely not change significantly in the next two years. The bottom line is that the most viable candidates are in high-cost processes, high-value, highly mobile assets, or in the tracking of containers in conjunction with passive tags or bar codes for low-cost items — this is where the return on investment is most justifiable. Keep in mind that leveraging existing wireless network infrastructure makes the RFID and Wi-Fi connection more attractive to some.

Battery Life and Refresh Rate Frequency

This is an important consideration because transmission frequency — how often the tag is programmed to send a signal or location report — affects the overall life of a battery. Make sure that the frequency matches the rate required by the business process. For instance, a hospital administrator may only need to see the location of a particular monitor every 45 minutes, since it is used during scheduled appointments with patients only. This could dramatically lengthen the battery life of the RFID tag, cutting down on replacement costs.


In our experience, accuracy levels currently available are sufficient for most implementations, as long as the customer is not looking for location within a millimeter, but read accuracy is something to think about as it relates to the business process requirements. The degree of certainty varies depending on signal strength and travel time, and in reality, should be based on the percentage of accurate reads within a given distance. For example, in one configuration you may find 90% accuracy within 2 meters or 85% accuracy within 3 meters. Providers make promises in this area, but make sure to test the specific configuration carefully so that the end user will know what to expect in the deployment.

Form Factor

RFID tags are available in a variety of form factors, and there are many options for attaching tags to different assets. In some cases, it’s as simple as using a little double-sided tape (not recommended!); in other cases, you might need to develop a bracket to clip the tag to a piece of equipment, or create a special form factor, such as a bracelet. Review your options carefully, and use the form that makes the most sense for the business process.

Environmental Conditions and Infrastructure

A field survey is one of the most important steps in any RFID implementation. The Wi-Fi signal, like all RFID signals, is susceptible to environmental conditions — thick walls, too much metal, the presence of liquids, etc. — that can impact the tag reading conditions. There are ways to work around these environmental constraints, including adjusting the density (or number and position) of access points (readers), the signal strength, as well as the type of location technique.

Security and Network Traffic

Probably one of the greatest myths about RFID is that it is inherently insecure. We’ve found that because RFID tags do not establish a data session the same way a laptop connected to a Wi-Fi network does, it does not represent the same kind of security threat. The conversation between an active RFID tag and the Wi-Fi access point is so brief that “eavesdropping” isn’t possible. As for concerns about network traffic, even in extreme cases, we have discovered traffic typical traffic does not consume more than 2% of network bandwidth.

Focus on the Business Process

For many, active RFID and Wi-Fi gets you into relatively unknown territory. Consider the technology as tools to streamline processes, improve supply management, and increase visibility, and you will be on the right path. End users that choose to work with a consultant or systems integrator save months of hassle and learn more quickly how active RFID and Wi-Fi create powerful solutions for what are truly common business problems. Remember to analyze the business case, and then test, test, test the concept before broadening the implementation.

About the Author

Lionel Carrasco has more than 20 years experience in IT consulting in the banking, insurance, transportation, retail, manufacturing and oil industries, in more than 12 countries.

More by Lionel Carrasco

About Neoris

Neoris is a global IT consultancy, systems integrator, customer application developer and leader in emergent technologies such as RFID.