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Rejected tags
29 March 2004

Solutions based on electronic tags RFID have a long way ahead before they will be usefully implement in business. There are a lot of technical and standardization problems still unresolved, no to mention security.

Author: Tomasz Grabowski
Translation: Aleksandra Malak
Called as “new”, technology of electronic tags RFID (Radio Frequency Identification) is in fact not that young-first identification systems, based on automatic signals send by radio waves appeared during the second World War. What is really new is miniaturization of sending systems, and as the result of it, the individual cost of RFID systems has been reduced. At the present their cost is in the level of 15-20 cents per unit, and in the next few years should decrease below 5 cents.

Tags price decrease means new trays of usage, which–for cost reasons-hasn’t been thought before. Intelligent tags could potentiality solve many problems of business network or logistic operators, as the form of merchandise and wrapping marking, and even common offices, for example as a tool for equipment stock-taking, and in case of system equipped in computational power/ability, they would make remote operations possible, by for example measurements or illumination control.

At this moment, a proverb “red light” should light up for net administrators. Why? Basically all technologies, which, even if there were not designed for business, for some reasons become their part, caused people responsible for computer science a headache. That happened with Internet, Windows systems, and lately the same situation occurred WLAN technologies.

Possibilities of usage for RIFD solutions had been widely presented by Antonii Bielewicz in his article: “Coś wisi w powietrzu” (CW 8/2004)- “There’s something in the air”, that’s why instead of dwelling upon it, I suggest to look at RFID solutions from strictly engineering side, and think, what challenges any company can expect, if it decides to implement them.

On the basis of RFID technologies lies radio communication, which uses many different frequency ranges. So fundamental requirement is to attend the same frequency range both by RIFD systems and reading apparatus which collaborate with them. RFID systems use most often one of three frequency ranges: low (approximately 125 kHz), high (13,56 MHz) and ultrahigh called UHF (850-900 MHz). There are also devices that work on microwave frequencies (commonly free frequency band 2,45 GHz), but this situation happens rarely.

Radio waves act differently in different environments. Frequency selection should not be accidental. Tags that are working in lower frequency band, are much cheaper than the one that works in UHF-they use less energy, and their signal, because of bigger wave length, better permeates through non-metallic objects. Those systems can be used especially for marking products consisting a lot of water, for example: fruits. A disadvantage of the chips which are working in this frequency range is a fact, that they can be read in relatively short distances.

Systems, which are using UHF waves, make possible communication on long distances, however they use much more energy and they have problems with permeation through most of materials. They are used, when on a distance between a tag and a reader are no objects, that is for example on products tray or some kind of boxes, cases, containers.

To complicate the case more, in different countries different frequencies are used. And so in Europe UHF band is 868 MHz, in USA-915MHz, and in Japan it is forbidden to use UHF in RFID devices. Moreover governments determine maximum of power for readers, to do not cause interference with other radio devices. Global Commerce Initiative Organization is trying to convince all governments to determine uniform frequency standards and power levels, but for now, their actions did not give any positive results. Also producers of this devices are trying to create systems, which would be able to work on many frequencies.  

Even thought many frequencies are used, there’s still the problem of waves permeation through water and metal. The highest frequency, the biggest waves are absorbed by them. Implementation of RFID technology in that kind of environment would require very precise tests and accurate readers layout, and even skilful merchandise placing in storehouse. It may appear that in case of some products, costs and problems connected with RFID devices might exceed potential advantages.

Technology without standards

RFID tags can be different from each other, not only in regard to radio frequencies that are used. We can distinguish two kinds of them: Active and passive. Active have it’s own battery, which is used for feeding logical circuit and for sending signal to it’s reader-even in the situation when it is not nearby.

Passive tags don’t have it’s own battery. They get energy from electromagnetic field generated by a reader instead (on principle similar to zooming access control cards in accommodations). There also occur such hybrid solutions, which are equipped with battery for feeding circuit, but for sending returnable information to a reader, they use energy contented in electromagnetic wave send by that reader.

Active and hybrid tags have 30-40m range, which should be admitted as relatively large, but they are more expensive than passive solutions (cost approximately one dollar). The  best application of those tags, would be for expensive products, which require long distance scanning, like containers or a wagons. Passive tags costs approximately 15-20 cents, but their range is only 3m. So they can be used only in case of products, which can be scanned from short distances.

RFID tags generated by different companies, also differ in their memory capacity and its type. On the average it’s 2 kB, so sufficient enough, to hold all necessary product information’s in it. Moreover, some chips enable saving new and deleting old product information’s. Usage of those tags is much bigger than non-recurrent tags, unfortunately higher-and sometimes multiply-is their price.

One device of that kind may cost even dozens of dollars. In this situation most of applications must be dropped off, the few left, is to use tags for marking expensive products like cars-tags would keep information about technical survey, services, subassembly replacement.

Tags which still grows

Preliminary practical researches shows, that in RFID nets many problems occur, which if that technology is supposed to become popular, should be solved as soon as possible. First of the problems is so called tags interference, which proceeds, when after sending a demand for hiding information to a tags net situated in a reader range, the reader gets more than one answer in the same time. Every producer developed its own method for solving that problem. In most cases, tags are designed to respond with a pseudorandom delay, and considering that those delays are counted in milliseconds it has no effect on speed action of the system itself.   

The second problem is readers interference. It occurs when tag is situated in a range of more than one reader, that is when ranges at least two readers overlap. Also in this case, the solution of the problem is to insert differences in time between readouts, however each producer uses its own techniques and algorithms. In a long period, in case of both tags interference and readers interference, it would be necessary to work out a standard, which enables cooperation of tags and readers from different producers. 

Third problem concerning RFID nets, is connected with multitude of information, that can be sent in a readers direction, after giving a question to a net. We can imagine a situation, when a number of tags in a range of the reader, is simply too big, or the content of the demand which was send to tags, cause a situation when tags must sent relatively a lot of information’s at once.

These situations would need middleware applications, which will intermediate in communication between a reader, and for example ERP systems. Their task may consist on managing queuing messages, and from the other side, on their preliminary analysis, to decide which should be send further. Instead of, for example currently inform about expiry date of all products in a warehouse, this application would inform only about those products which expiry date was just exceeded. It may also generate a warning, in situation, when the amount of given products in a warehouse, is dropping below some restricted level.

Those softwares are already offered by IBM, Microsoft, Oracle, SAP, Sun Microsystems, and also by a less known companies like ConnecTerra, Manhattan Associates or Provia Software. Nevertheless, those implementation should be threaten more like a test, because the expectations of a potential clients, and the awareness of technology possibilities under suppliers side, are still evolving. “The situation is changing literally from week to week”-says Christine Overby, Forrester Research analyst.

With investments in products of any mentioned company, we should wait, until the bigger pilotage projects will be finished. Especially that individual solutions, even from pretence, are not compatible with the others. Though in the frames of one company we can easily choose one tags and readers caterer, it’s hard to consider the fact, that all companies connected with trade turnover in frames of the same logistic chain, would supply in the same caterer. Creation of standards seems absolutely indispensable to make RFID technology disseminated.

Not private and not safe

New problems are still appearing, For example, it appeared that in shops which dill with a wholesale of clothing, when scanned clothes lie flat on the ground, all tags are read every time, but when the clothes hang on the hanger, the ratio of read tags total up approximately 96%

Many problems are also connected with a limited range of transmission from tags to a reader. Metal and concrete obstacles absorb even weak signals and electric engines make disturbances. In one case, even a glue used for sticking tags into a product become a problem, because in low and high temperatures it lost it’s qualities.

RFID tags stir up anxiety of disturbing privacy. The exact tracking of the way that every product takes, may enable company the access to many information’s about peoples purchase customs, and that would brake their right to privacy. Against that background many serious argues between trade nets, which experimented with RFID tags, and social organizations happened. That’s why there is a chip kill function in tags, which allows to delete all information’s saved in it, and even completely deactivate the tag. That operation can be carry through with a usage of a simple reader, for example  by the cash register.

The anxiety of producers, and the consumers also, stir up the security level assured by RFID systems. Both, in presently used Class 1 EPC specification, and expected in this year Class 1 Gen 2 EPC there are no mechanisms to encode or control access to data stored in tags. Other words, in a very easy way we can read data from neighbouring
tags, and sent any data to a reader. This can become the biggest barrier for implementation of RFID systems.

Waiting for its turn

Potential abilities of RFID nets are undoubtedly very promising. Nevertheless, it’s hard to not see that form enterprises point of view that technology is still origin. On solidly secured solutions and branch standards we have to wait few more years.

ICD foresees, that in a year 2008 the market of RFID solutions will get the value of 1,3 billion USD. If the forecasts will prove, we can expect a flood of products equipped in electronic tags, which can facilitate the existence of not only the big companies and stores, but also the citizens. In expectation for a boom it’s worth to abstain from investing in new technology.

All interested with RFID subject, should trace pilotage programs realized by the biggest companies. Those greatest players like Wal-Mart will define the track of expansion for RFID solutions. If they succeed, others will follow.