The Race to Make Passive RFID Real-Time

Passive Radio-Frequency Identification (RFID) has, until recently, been considered to lie outside the realm of Real-Time Location Systems (RTLS), mainly because it does not satisfy the requirements of the first two letters of the acronym: being real-time. However, companies like Zebra Technologies and RF Controls have recently developed and are now rolling out devices that can track RAIN (passive and ultra-high frequency) RFID tags in real-time and with a sufficient reading range for RTLS. The value of this development for RTLS lies in the fact that passive RFID tags are vastly cheaper than any competing RTLS location technology tags, like Bluetooth, Ultra-Wideband (UWB), or Wi-Fi. Therefore, the breakthrough of developing real-time passive RFID tracking is likely to deeply disrupt the RTLS ecosystem and give other location technologies a good run for their money.

Passive RFID tags, being battery-less, suffer from similar energy constraints as other passive location technologies. The tag is not able to constantly broadcast its location like an active one would. Instead, it must wait for a reader to send a beam in its direction, so it can reflect the signal back and answer the query. Together with short reading ranges, these limitations have meant that passive RFID has been used mostly in chokepoint applications. In chokepoint uses, a tag is only detected when it passes through a fixed detector. There is no indication of the exact position of the tag with respect to the reader, other than that it is “within reading range.” Furthermore, it can only determine the last reader in the tag was in the range of, which does not give a real-time indication of its location. Thus, passive RFID has so far failed to satisfy the prerequisites of RTLS. This scenario is set to change, however.  

In early 2019, RF Controls unveiled its new CS-445B RTLS RFID reader. It is claimed that the reader will work with any RAIN RFID tag, but the company finds that Confidex’s tags work best. The reader possesses a 13-meter reading range, and a location accuracy of about 50 cm. Judging from Confidex’s demo of the technology, it appears that tag locations are updated approximately every two seconds. With a reading range that is longer than that of traditional passive RFID and closer to RTLS technologies like UWB and BLE, RAIN RFID can now go beyond chokepoint applications. Further, location updates taking place every few seconds, it is fair to characterize it as truly real-time. Similar specifications can be found in Zebra Technologies’ ATR7000 reader, with the difference that this is an overhead reader. To locate tags in real time, Zebra’s reader uses a wide-angle antenna array that can beamform and steer hundreds of narrow reading beams in different directions simultaneously. With information on the beams’ directions and the tags’ responses, it is possible to pinpoint the tags’ locations. Zebra Technologies also claims that its reader can detect if the tags are moving and in which direction.

The price point of these readers has not yet been disclosed, but with tags that can cost as low as eight cents per unit, or even less in bulk, passive RFID RTLS will be especially appealing to verticals that need to deploy large numbers of tags, like healthcare and manufacturing. These are verticals in which asset tracking is especially prominent, with RTLS being used to track tools, pallets, and carts. They can also assist with Automated Guided Vehicle (AGV) tracking and navigating. Besides presenting business owners with information to make their businesses more efficient, these solutions can also leverage geofencing in order to reduce asset loss and larceny. In such implementations, each deployment might employ thousands of tags. Therefore, tag costs constitute a significant fraction of the Capital Expenditure (CAPEX) associated with such deployments. If a company decides to reuse said tags instead of disposing of them, the OPEX associated with tags can be significantly reduced as well.

RTLS companies have already realized that the future of RTLS does not lie in active RFID. ABI Research’s Indoor Location/RTLS (MD-RTLS-2019) market data shows that growth for active RFID tag tracking is slowing down. While active RFID tags saw a 66% Year-over-Year (YoY) growth in shipments between 2016 and 2017, this number is going to drop to 21% between 2024 and 2025. This fall is due to the fact that other forms of active RTLS, chiefly Bluetooth, have both tags and readers that are considerably cheaper and offer comparable tracking abilities. However, both the Bluetooth and RFID forms of active RTLS will struggle to compete with passive RFID RTLS, particularly in high tag volume verticals. In such scenarios, the total CAPEX of the RTLS implementation is largely driven by tag prices. If the passive RFID option offers the same benefits as its active counterparts, then, as explained in Overcoming the RTLS Scalability Challenge (IN-5349), its extremely cheap tags will help the contractor scale up and drive ROI much faster. The Healthcare and Manufacturing verticals will generate, in 2025, US$1.8 billion in revenues from tags and readers for RTLS. Should passive RFID claim even a very modest slice of this market, for instance 5% of revenues, it will be generating US$90 million worldwide. 

As previously discussed in A New Wave of Harvesting Ultra-Low-Power Devices May Disrupt RTLS and Outdoor Tracking, but Challenges Remain (IN-5418), other technologies, namely Bluetooth and UWB, have also started exploring the possibilities of passive real-time tracking. In order to compete with the lower costs of passive RFID, they will need to differentiate themselves by implementing basic sensing capabilities (like temperature and pressure) or better data encryption and security. However, in principle these can also be implemented in passive RFID. Thus, the companies overcoming the limitations of passive RFID have also potentially opened the doors to RFID constantly haunting and threatening the dominance of Bluetooth in the asset tracking ecosystem. All of this is conditional, however, on passive RFID real-time tracking delivering on its promises. Very importantly, it needs to maintain the claimed 13-meter reading range in real-life conditions: with assets blocking the way, dynamic metal parts, and people walking around the venue. Ideally, over time the companies will even increase this range by improving on the technology. We will only be able to assess that once these solutions start to roll out.

Assuming the reading range and accuracy can be maintained in real-life conditions, this technology is likely to eat into a significant part of Bluetooth and active RFID asset tracking solutions. Perhaps more importantly, however, it could unlock a new segment of the market for RTLS. There is a large number of factories and warehouses that make use of passive RFID for chokepoint applications. They have not moved into RTLS because deploying Bluetooth or UWB anchor points and substituting all of their hundreds or thousands of tags might not be justifiable from an ROI perspective. Since Zebra’s and RF Controls’ new readers work, in principle, with any RAIN RFID tag, for these businesses it would just be a matter of swapping readers to switch from chokepoint tracking to RTLS. A much lower barrier. The process of partially eating into other RTLS technologies would probably be slower due to vendor lock-in and the usually high costs associated with full RTLS deployments. It will likely take at least 5 to 10 years to start seeing a noticeable effect. However, converting chokepoint RFID businesses into RTLS is likely to be faster, with noticeable effects in 3 to 5 years.

With even passive RFID monitoring in the horizon, these new developments in the RFID world show that there is no clear champion communication standard for the enormous addressable market of asset tracking and monitoring. This fight is clearly going to continue well into the 2020s and is yet another indication that RTLS integrators will need to become more horizontal and focus on solutions, rather than technologies, should they wish to survive the tug-of-war currently taking place between the many indoor location technologies