In the emerging “Internet of Things” (IoT) market there are numerous references to automated identification (AutoID) and sensor technologies such as Radio Frequency Identification (RFID), NFC, and Beacons. I have heard statements such as “RFID is going to be really important” or “NFC will take over the payment industry” or “smart wearables are blowing up” from well intentioned individuals who appear to have limited experience with these technologies. Since I do have a bit (ok, a lot) of experience in this area I thought it would be helpful to share among the masses how these technologies work and how I believe they may fit into the emerging IoT market.
While Radio Frequency Identification (RFID) was actually developed by the British in WWII it became most widely know by IT professionals as a result of a mandate Walmart placed upon their suppliers in 2003. This mandate required that certain consumer packaged good companies apply passive RFID “smart labels” on cases and pallets of products that were supplied to Walmart. Walmart did a great job of telling suppliers how Walmart would benefit by using RFID to streamline supply chain operations and maintain optimal inventory levels in stores. The suppliers who were being forced to invest in RFID and assume the cost of the RFID tags were left to their own devices on how they might get some internal benefit from using RFID. While the suppliers put up a good fight everyone ultimately fell in line and the Walmart mandate continues to hum merrily along.
How RFID Works
An RFID tag is a fairly simple piece of technology. It includes a small silicon chip capable of storing a serial number or other limited identifying data along with a small antenna. The overall package can be quite small and can be integrated into adhesive labels for cases and pallets, high durable tags for on-metal performance in harsh environments, security cards, or implanted in pets, for example. Such RFID tags are passive meaning that they have no onboard power. Passive tags are brought to life by the RF energy sent wirelessly by a suitable RFID reader. The read distances for passive RFID tags is determined by the technical implementation (LF, HF, UHF), the RFID reader power and antenna design, and the RFID tag design. Over the past decade the most rapidly growing segment of the RFID market is for UHF RFID technology that supports the EPC Global Generation 2 (EPC Gen2) Standard.
The primary components that make RFID “Work” areTags and Readers (aka Interrogators). From an IT perspective RFID readers are little more than peripheral devices that read/write data from/to RFID tags and transfer this data to back end IT systems. Fixed Readers are mounted to a specific location (e.g. a dock door or similar portal) and require one or more external antennas and associated cabling for an increased read area. Less powerful Mobile Readers offer greater flexibility but with a decreased read range as compared to fixed readers.
RFID tags fall into three primary categories: Passive, Battery Assisted Passive (BAP), and Active. Passive RFID tags operate by harvesting energy through electromagnetic waves provided by the RFID reader to power up an integrated circuit in the tag which then transmits and receives information using either inductive coupling or backscatter:
- Inductive coupling (Near Field) works when a tag and reader transfer energy through a shared magnetic field. Near Field RFID tags have a relatively short read range of just a few inches. This is how the increasingly promoted NFC (Near Field Communications) technology operates.
- Backscatter (Far Field) works by reflecting electromagnetic waves back in the direction which they came from. Far Field tags such as EPC Gen2 passive RFID tags can support much longer read distances depending on tag size, reader configurations and power, and environmental conditions.
Passive RFID tags fall into three sub categories defined by their operating frequency:
- Low Frequency Passive (LF) tags operate at 125 – 131 kHz and communication with LF readers using indicative coupling. Read distance for LF RFID is typical no more than a few inches. LF is unique among passive RFID technology in its ability to transfer through thin metallic substances and items with a high liquid content. Typical applications for LF RFID include access control and animal tagging.
- High Frequency Passive (HF) tags which operate at 13.56 MHz and typically follow the ISO 14443 or ISO 15693 standards to communicate with an HF reader using inductive coupling. Similar to LF tags HF typically has a read distance of no more than a few inches and are commonly used to support transit ticketing and library check in/check-out applications.
- Ultra-High Frequency Passive (UHF) tags (e.g. EPC Gen2 tags) harvest energy from the RFID reader which stimulates the tag antenna to power up the chip. The tag then uses backscatter to send data from the chip back to the reader. The read distance on UHF passive tags can vary a great deal from just a few inches to over 80 feet depending on reader power and tag design. UHF is rapidly becoming the de-facto standard for supply chain, retail inventory, and asset management applications.
Tags that require an on-board power source (battery) include:
- Battery Assisted Passive (BAP) tags operate in a way similar to UHF passive tags with the exception that they use battery power to significantly boost the read range of the tags (over 100 feet). BAP tags must first be contacted by the RFID reader (a.k.a Reader Talks First) before the battery is engaged to power up the chip and broadcast data back to the reader. The downside to BAP tags is that the batteries on these tags typically only last a few years years, after which they operate as a standard passive UHF tag with a much shorter read distance.
- Active RFID Tags use battery power to effectively act as a beacon that is identified up by any active reader within a range of approximately 300 feet. Active tags operate in a manner where the tag broadcasts its unique identifier, and in some cases sensor data, which is then transmitted to an antenna. For Real Time Location Systems (RTLS) the active tags need to be picked up by more than one antenna so the software can identify the location of the tags through proprietary triangulation algorithms. Active tags suffer even more limitations than BAP tags, when the batteries run out they stop working. Active RFID tags are typically proprietary and subject to vendor lock-in, and as a result, can be significantly more expensive.
EPC Gen2 UHF Passive RFID Tags – The Global Standard
With the exception of transit ticketing and payment applications which use HF RFID, UHF tags that support the EPC Gen2 standard are by far the most common around the glob4. The reasons behind this are as follows:
- Major retailers and the US DoD mandates that suppliers apply EPC Gen2 labels to cases and pallets of products shipped to their respective distribution centers.
- EPC Gen2 has been adopted by ISO (ISO 18000-6) and is truly a global standard supported by all leading RFID technology manufacturers.
- The costs of UHF RFID tags and readers continues to drop as the industry matures making it easier for more organizations to justify adopting the technology.
Because different regions of the world use dissimilar frequencies in the UHF range, many UHF tags are tuned to perform best in a particular region (e.g. 915 MHz for the US, 868 MHz for the EU). However, a growing number of tag providers are developing tags that perform equally well in all regions.
In the world of EPC standards, no personal consumer information is stored on RFID tags. The limited data (96 bits, stored in HEX) referenced by the EPC code that is stored on the tag is maintained in one or more secure databases (e.g. manufacturers, distributors, retailers, etc.) so that these organizations can efficiently track to movement of goods through the supply chain. If someone were to hack into a system where this information was stored they may learn who manufactured the product, when it was made, product ID number, etc. – pretty boring stuff and nothing that you can’t read on the packaging. Reading UHF Gen2 tags happens in milliseconds; encoding the tags takes a good bit longer. The EPC Gen2 standard requires support to re-encode tags but in practice once they are encoded for a specific purpose the are rarely re-encoded.
RFID – Facts, Myths, & Innovation
The easiest way for someone to understand RFID technology is to suggest it’s like electronic barcode. The primary difference being that barcode readers require “line-of-site”; the barcode scanner must “see” the lines of the barcode in order to read the data. This also means that barcode readers can only read one barcode at a time. RFID does not require line of sight as tags can be read through a variety of materials. For supply chain applications the key benefit of RFID is its ability to provide granular data on unique items, cases, and pallets of products as they move from manufacturing through consumption. This differs from linear barcode systems that apply codes that are often not unique (.e.g. every widget has the same barcode). RFID readers can read multiple tags in milliseconds at one time where barcodes scanners are limited to processing one barcode at a time.
A great deal of attention has been paid to the use of RFID for supply chain applications ever since Wal-Mart announced their RFID Supplier Mandate. The value proposition for consumer goods manufacturers continues to be elusive even when the RFID labels are as cheap as $.10. An area that gets much less attention, and has significantly more value for enterprise organizations, is using RFID for managing high value assets including IT assets, healthcare equipment, specialty tooling, shipping containers, and aircraft parts. Tags for asset management applications can cost several dollars each but the value proposition to the end users easily justifies the added cost.
In the early days of the RFID mandates privacy advocates were concerned that RFID tags will enable companies to track consumers to influence purchasing habits and invade their privacy. The physics of passive UHF RFID alone dictate that it is a really lousy way to try to track some let alone steal their personal information. I would be much easier for a thief to simply steal your wallet. The truth is that if you have a mobile phone, surf the web, use a free email service like gmail or yahoo, and make purchase with credit cards, you have already agreed to trade off a great deal of your privacy. For individuals concerned about privacy having an RFID chip in a credit card that you willing hand over to strangers in restaurants RFID is the least of your worries.
RFID tag designs vary based on the type of item being tagged and the operational environment. For cases and pallets of consumer goods or as hang tags on apparel items the most inexpensive RFID labels will work just fine. Based on volume these tags are now priced under $.10 per tag. These inexpensive RFID abele however will not work in more demanding applications and will not work when applied to metal objects. For asset management applications when most items are metal a tag designed for on-metal applications must be used. On-metal tags come in a wide variety of shapes and sizes. Construction of the tags also varies based on the environment conditions in which the tag mud operate. Simple on-metal tags for IT assets in office environments are less expensive than tags designed to survive on construction equipment in Alaska. Determing which tags are best for your applications requires the type of expertise provided by companies like RFID TagSource – which is a blatant plug for our RFID company.
It is important to note that passive RFID tags have no inherent location/GPS capability – location information is determined strictly by a reader “checkpoint” (e.g. tag ABC passed reader 123 at 10:40 AM…). It is also important to note that any RFID chips embedded into credit cards, transit cards, NFC stickers, etc. are all Near Field tags that can only be read when the tags share the same magnetic field with a reader and are limited to a read distance of a few millimeters Regardless of the claims of self appointed privacy advocates…Passive RFID tags can NOT be tracked by satellites and thieves will NOT be able to use a handheld RFID reader to steal your identity while you hand your credit card over to teenager you’ve never met at your local coffee shop.
Contactless Cards and NFC
Most common payment systems (e.g. credit cards, ATM cards, transit tickets, etc.) require physical contact between a magnetic strip on the back of a card/ticket and a magnetic head in a reader/terminal. Over time card reader machines need to be repaired or replaced due to wear and tear. For a small restaurant it is not such a big deal. For a large transit systems with thousands of ticket dispensing machines and turnstiles this represents a huge expense. Transit systems in Europe and the Asian Pacific region have long adopted High Frequency (HF) RFID “contactless smart card” systems eliminating a great deal of the expense of maintaining equipment.
NFC builds upon the previous “contactless smart card” standards by adding more robust and secure two-way contactless communications. The benefits of using NFC for contactless transit tickets by daily users of public transit systems are understandable. Pushing NFC into credit cards and mobile phones to replace traditional credit cards is less understandable. I am already on record stating NFC is DOA in the US and the recent announcements regarding NFC and Apple Pay do little to alter my opinion. Mag strip credit cards are very easy to use and credit card terminals are ubiquitous. NFC is currently very difficult to use as NFC terminals are few and far between – and even if you can find one chances are the retailer does not know how to process an NFC transaction.
I recently met several NFC proponents at a local IoT meet up who were espousing that NFC is going to be “HUGE”. When I asked them about their personal experiences paying with NFC it was as if I called their baby ugly. I rest my case.
In a consumer sense IoT “Beacons” are a fairly recent development primarily being promoted by Apple via their iBeacons™. “Beacons” are low-energy bluetooth devices that operate by broadcasting a unique identifier to a specific local area. Devices with applications that support receiving beacon notifications will then be made aware of a specific event (e.g. secret sale on funky socks for beacon users) along with an estimation with how far away the user is from the beacon. The only examples I have heard for beacon applications come from the world of retail sales. I am admittedly at the end of my knowledge of beacons, but If you are concerned about your privacy and fearful technology could be used to influence your purchasing decisions…let the beaconed beware.
Sensors require power, which pretty much eliminates all forms of passive RFID tags. Active RFID tags have had sensor capabilities such as monitoring shock, vibration, temperature, humidity, etc. for many years. A limited number of battery assisted passive (BAP) tags are also adding sensor support. The downside of these active RFID sensors is that they are often proprietary and very expensive. A better option would be to look at Low Energy Bluetooth sensors that are increasingly available at more attractive price points and do not require proprietary hardware/software to gather the sensor data.
So there you have it – a basic primer on RFID, NFC, & Beacons and my view of how these technologies may fit in the emerging IoT market. Keep in mind that RFID, NFC, Beacons, etc. are enabling technologies; the real value comes from developing intgrated solutions that may include RFID, Mobile, WiFi, Bluetooth, Cloud, and legacy enterprise applications. Do not make the mistake of looking for “An RFID Solution”. Do your homework, develop your requirements, and combine best of breed technoogies that best support your specific needs.
Comments and questions are always welcome and appreciated. I can be reached at kevin@TheIoTGuy.com