20 January
Chips with everything - an RFID primer
Radio frequency identification (RFID) technology was first envisaged just after
the Second World War, when transponders for aircraft were developed using a
precursor of the technology, as outlined in The
history of RFID. Today, thanks to advances in miniaturisation and radio
communications, millions of RFID tags now litter our retail products,
warehouses, medical institutions, and even our pockets. What are they, how can
they be used, and how are they developing in line with future requirements?
Passive RFID
The most common type of RFID is known as a passive device. It requires an
external electromagnetic source to activate. In a passive scenario, a reader
provides enough power for passive fight the tag to transmit its data over a
short distance. It is primarily used for applications in which a dormant item
must be read infrequently, such as in retail, where tags on items of clothing
may occasionally need to be queried.
There are many other applications for passive RFID.
Active RFID
Active RFID has a number of
differences compared to passive RFID. It contains a battery, allowing it to
autonomously broadcast its signal, without waiting to be activated by an
external reader. It also has a much longer range, of 100 metres or more,
compared to the 3 metre range inherent in passive RFID tags. Generally, active
RFID will contain more data, and will cost somewhere in the region of 50 times
the price of a passive tag.
The benefit of active RFID tags is that they can be used within a large
designated area, such as a warehouse, or a road toll system. Conversely, the
shorter range of passive RFID tags makes them more suitable for scanning very
narrow areas through which high volumes of goods will pass (such as a retail
point of sale system).
Because of its broader range, active RFID has significant potential in
enterprise applications such as ERP, where supply chains must be monitored in
environments that cannot be very closely scan. One example might be shipping
containers, which might be scanned from a dock while they are sitting on a
boat.
Machine to machine (M2M) applications can be used to automatically scan active
RFID tags in such environments, feeding the data through to ERP software
applications that can use it to update product and material workflows. For
example, a container of chilled food might log its temperature constantly on an
active RFID sensor, which might communicate its logs to an M2M application when
it hits the port. This could relay the history to an ERP application, which
might automatically adjust the scheduling of the food on retail shelves based
on the data. ERP applications such as SAP and Oracle support RFID, but commentators
suggest that some middleware customisation may be necessary to make it work
seamlessly.
NFC and mobile phones
Based on RFID, Near Field Communication (NFC), as promoted by the NFC Forum, is a two-way communication
technology that works over much shorter distances, measured in centimetres
rather than metres. Consequently, it is referred to as a contactless
technology, which generally requires one device to be touched to another (or at
least waved very close) for a data transaction to be completed.
One area of NFC that is beginning to open up is low value transactions. MasterCard
operates a system called PayPass, in which a card preloaded with plants can
be tapped against the reader to pay for groceries, and other items. Visa has a
similar system called payWave.
Oyster card, designed
to store credits for use on the London public transport system, also uses NFC
technology. Users charge up the card by paying at a kiosk, and then touch the
card against a reader when they want to begin a trip. The card is then debited
to reflect the payment.
The ultimate logical conclusion for NFC technology is to put it directly into
mobile phones, which are becoming hubs for general day-to-day interaction with
social networks and consumer services. Instead of touching a card to pay for a
low value item or gain paid admission to a service, users will be able to touch
their phones to a reader instead.
Projects supporting this idea are already underway. For example, Orange
conducted a trial with Reading Borough Council in the UK in late 2008,
enabling members of the public to pay for past services using a Sony Ericsson
mobile phone with an NFC chip and a SIM card to authorise payment.
Security
However convenient NFC technology may turn out to be, there are also
significant security implications. In June 2008, Dutch academics developed a technique
to clone an access card using the Mifare
chip, which forms the basis for the Oyster card, among many other
smartcards.
Other security problems have been discovered with RFID. For example, Adam
Laurie, a researcher specialising in RFID security, demonstrated how to clone
the UK's recently introduced biometric
passport in 2007. He managed to guess a key, printed inside the passport,
which is meant to give access to the encrypted data on the RFID chip. They key
was not created randomly, and he could guess it using specific facts about the
recipient of the passport. He then used the key to read the chip from a
demonstration passport which was still inside a sealed envelope, as it would be
sent in the mail. This would then enable him to clone the passport.
Cost and reliability
The manufacturing cost of passive RFID tags is far lower than their active
counterparts, because of the simple components, and the lack of a battery. As
large retailers including Wal-Mart mandate the use of such tags, it is hoped
that the economies of scale will continue to bring down costs. Reliability
problems, which were an issue with some of the earlier RFID tags, are now being
resolved thanks to better technology. It is becoming easier to read these tags
when they are positioned on and around lots of metal objects such as clothes
hangers, for example.
Standards
Perhaps the biggest barrier to the take-up of RFID is the lack of
standardisation. There is no single body governing a global standardisation
movement, although EPCGlobal, an
organisation set up to standardise electronic product code techniques, is
currently the main contender. EPCglobal created the EPC Gen2 standard, focusing
on passive RFID, and designed to bring the cacophony of different protocols
underpinning the medium together.
