technologies

This page offers a very basic introduction to RFID technologies and their development.

It covers -

• introduction
• classes of tags
• reading
• spectrum - what frequencies are in use
• drivers - what is driving development
• development challenges

     introduction

RFID technologies centre on

• tags (aka chips) that emit short-range radiofrequency signals
• devices (aka readers) that pick up the signal and that may be networked to databases of varying sophistication
• databases that hold customer account, stock control or other information that is used by a single entity or by multiple entities
• software that integrates information supplied by the tag to the reader with information held in one or more databases

From a transmission perspective there are essentially two types of RFID tags: active and passive.

An active tag - used in for example a vehicle traffic management system for automated payment on tollways - uses its own power source to contact the reader. That power enables transmission of a signal over a greater distance (eg up to 100 metres) than that of a passive tags. The advantage is, however, usually offset by the greater cost, size and weight of the tag.

A passive tag does not require its own power source. The tag instead derives its power from the electromagnetic field created by a RFID reader. That generates sufficient power for the tag to respond to the reader, ie to supply its information.

Passive tags have a shorter range than active tags, varying from a few centimetres to a few metres and affected by barriers such as metal shipping containers or concrete walls. However, the absence of an integrated power source means that they can be smaller (one state of the art tag is as small as half a millimetre, with a 128-bit ID number), potentially more resilient and - through economies of scale - substantially cheaper.

     classes of tags

From a content perspective we are seeing the emergence of three classes of tags: 0, 1 and 2.

Class 0 are factory programmable only. Class 1 tags can be programmed by the retailer or supplier. A proposed Class 2 will feature more memory and data.

RFID tags can be incorporated in plastic security cards, paper passports, consumer packaging or even in living creatures. Typically they are being used as unique or generic identifiers (eg for a particular card, object or class of objects). There is major commercial interest in uniform numbering schemes, similar to those used for product barcodes (and in ISBNs and other metadata), such as the emerging global Electronic Product Code (EPC) for use in supply chains. They can also be used for authentication purposes.

The tags can used in isolation - for example solely as a vehicle's registration number - or can be integrated with sensors that collect a range of data, for example temperature or salinity.

     reading

Use of radiofrequency means that they can be read in proximity to a reader and thus are not dependent on physical contact (as in, for example, a magnetic stripe card) or direct line of site (eg a laser-scanned barcode).

An RFID tag can be read in the dark, in smoke, in bright sunlight or other environments where visual recognition is difficult.

Subject to interference or transmission barriers, reading can also be almost instantaneous.

That speed of data acquisition is particularly attractive for supply chain applications ranging from manufacturing through to retail, with for example the diverse contents of a shipping crate or shopping basket being identified in less time (and with less labour) than is required to read the barcode on an individual item.

     spectrum

In discussing networking and the global information infrastructure we have noted that 'wireless' is a shorthand for applications using a range of frequencies.

Various RFID schemes thus use different frequencies that include -

125 and 134.2 kHz
433.05-434.79 MHz
1.77-2.17 MHz
2.93-3.58 MHz
7.2-10.01 MHz
13.553-13.567 MHz
918-926 MHz
2400-2450 MHz
5725-5795 MHz
5815-5875 MHz
24000-24250 MHz
5795-5815 MHz

Some of those frequencies are (or will be) shared with other devices and applications.

     what is driving development?

Development of RFID technologies and applications is being driven by four factors.

Firstly, the declining cost and increased reliability of small passive tags, heading to the point where they can be routinely incorporated in disposable consumer items rather than restricted to overall supplychain shipments (eg to identify a can of softdrink rather than a shipping pallet).

Secondly, perceptions that some RFID applications potentially have a strong business case, with appropriate ROI over a three to five year period.

Industry group EPCGlobal has suggested that US retailer Wal-Mart would save US$407 million by having suppliers attach RFID tags to all pallets, based on industry-average operating margins. Requiring an RFID tag on every item would save US$7.6 billion, primarily in labor costs associated with loading, warehousing, stock management within stores and checkout operation.

Thirdly, claims that RFIDs can leverage substantial existing investment in commercial EDI (with greater flexibility and detail than barcodes), enable dynamic pricing (similar to online airline demand-based ticket pricing) in retail environments or offer practical solutions to hitherto intractable problems such as tracking livestock from pasture to the table.

Those claims have been endorsed by major hardware, software and integration service providers - such as IBM - although much analysis is patchy.

Finally, the technology is being spruiked by particular vendors - some of which sound increasingly zany as they burn the last of their capital - who are offering solutions in search of problems.

     development challenges

Key challenges are -

• the cost of tags, with passive tags currently costing between US$1 and 20 cents. Large-scale commercial adoption - particular for item by item identification (rather than generically by product type) of low-value items in supply chains - is dependent on costs being reduced to a small fraction of those figures. At the moment tags typically represent upwards of 60% of implementation costs, with other spending on systems integration and on readers.
• agreement on standards for tags, devices and data (in particular numbering schemes that are sectoral rather than restricted to a particular vendor/user or that are used in most links of a supply chain)
• reluctance of potential commercial users, notably small organisations, to invest in RFID technologies and more broadly in EDI. As with uptake of barcodes, implementation is accordingly often driven by a few dominant actors in the supply chain (WalMart for example has attracted attention) or as an extension of existing EDI in particular sectors such as auto and computer component manufacturing/assembly
• optimisation of technologies (eg 'fixing' small passive tags in wet or cold environments) and deepening of knowledge about placement (eg best positioning in a crate, shipping container, vehicle, package or pet)
• addressing consumer concerns (and subsequent indecision or delays by regulatory bodies) over "the spy chip" per se or the handling of data that might be collected using RFIDs. Consumer perceptions of the balance between benefits and threats are highlighted in a 2001 Auto-ID survey (PDF).

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