WSN and the New Internet of Things

25 Sep 2012

The Internet of Things was conceived in Massachusetts Institute of Technology in 1998. It was believed that RFID tags could be made so cheaply that they could be fitted to trillions of items, tadalafil even printed directly onto them like most barcodes today. After all, recipe about three trillion items of consumer packaged goods are made yearly in the world and it seemed that we were headed for one trillion postal items yearly. Barcodes and phosphor dots were woefully inadequate for monitoring at a distance and sometimes at speed: these things could be dirty, torn and misoriented and trying to read them one at a time was ridiculous. Automated monitoring en-masse throughout the value chain could make logistics faster and more cost effective, reduce theft and counterfeiting and provide other benefits such as no stock-outs in shops. All that was needed was a new numbering system to handle more items and a few simple improvements to systems and, yes, ways of making the RFID tags for one cent or less, would be easily achieved by design tweaks and sheer volume. It has not turned out that way.


Human frailty intervened in the form of committees writing specifications of military complexity for a host of “nice-if” features, this making the tags more expensive than necessary. Even if that error had not been perpetuated, there was the problem that retailers are technophobic beyond their databases and terrified of anything regarded, even by a handful of people, as a potential threat to privacy. The usual ruse of requiring the suppliers to do it all for nothing, despite the benefit almost entirely accruing to the retailer did not work. It had worked with anti-theft tags but with RFID the costs were one hundred times larger and the suppliers of fast moving consumer goods, with their wafer-thin margins, dragged their feet even though they had unloaded hundreds of millions of dollars of losses on their over-enthusiastic, naive RFID sources. Many in the value chain went to the wall and only certain things such as tagging apparel became successful, with demonstrable paybacks. True, some countries are proceeding as a matter of national prestige rather than payback. For example Russia intend to RFID tag all postal items but, at best, it all adds up to tens of billions not trillions yearly, woefully inadequate in getting costs sufficiently low. Companies printing RFID to make it cheap have largely collapsed or failed, as yet, to get yield that is high enough for viability. Those making primitive, very cheap ink-stripe RFID run afoul of the over-specifying by retailers and others. For example, most passive tags are required to be read-write yet very few use that facility once it is in place.


Nonetheless, a catchy title like Internet of Things is too good to go to waste so it has been high-jacked by some of those making and using active tags and their systems i.e. ones with their own on-board power source which is usually a battery today. Over the last decade, the money spent on active RFID tags and systems has grown from around 10% of all RFID to something more like 30%. The percentage of all RFID projects that are active RFID has similarly grown, as monitored in the IDTechEx RFID Knowledgebase  of 4500 projects in 124 countries and growing all the time. In the past, active RFID usually meant things like your car key fob opening or locking the vehicle at 30 meters, one-on-one. Some big military money went on active RFID with sensing but that was also usually one-on-one. However, nowadays the primary attention is on applying second generation active RFID called Real Time Locating Systems (RTLS) where, usually but not always, the tag knows its location thanks to “seeing” several RF emitters and applying various measurement principles such as time of arrival, angle of arrival, received signal strength and so on. More and more, this is done without human intervention in contrast to the nurse pressing her RTLS pendant in emergency, which was an early success. It becomes Machine-to-Machine (M2M).


Then there is third generation active RFID called Wireless Sensor Networks (WSN) or, in Korea, Ubiquitous Sensor Networks, where the tag is called a node because it acts as both RFID tag and RFID reader. To qualify for this terminology, it has to be a mesh network in computing terms, self-organising and self-healing. Drop them from a helicopter on an oil spill and they form a useful RFID system by themselves. This is all very like the internet so, bingo, let us call it the Internet of Things without a retailer in sight and with sensing in every case.

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