Jan 26, 2009The Australian Communications and Media Authority (ACMA), the government body responsible for regulating radio frequencies, has approved the use of ultrahigh frequency (UHF) RFID interrogators transmitting up to 4 watts EIRP (effective isotropic radiated power), removing restrictions and bringing the country into line with international practices. The decision follows four years of testing on the use of 4-watt RFID interrogators by GS1 Australia and could lead to a significant increase in take-up of the technology.
The majority of countries around the world limit RFID applications to 4 watts EIRP or 2 watts ERP (effective radiated power), which is the equivalent to 3.2 watts EIRP. But ACMA was concerned about the potential interference of UHF RFID systems in close proximity to GSM-based mobile phone systems and restricted the use of such systems to 1 watt EIRP at the 918 to 926 MHz band under a Low-Interference Potential Devices (LIPD) license.
Typically, RFID devices are imported to Australia from the United States, where UHF RFID interrogators and tags operate in the 902 MHz to 928 MHz band. In Australia, however, GSM-based cell phone service provider Vodafone Australia has the right to utilize the 907 MHz to 915 MHz frequency band, while RFID interrogators and tags are allowed to operate at 918 MHz to 926 MHz.
In 2005, ACMA awarded GS1 Australia with a scientific license allowing the standards-setting organization to authorize and oversee licensing arrangements with Australian companies to test site-specific RFID systems operating between 920 MHz and 926 MHz up to 4 watts EIRP. The aim was to ease concerns of interference by testing UHF EPC RFID systems in close proximity to GSM-based mobile phone systems.
In July 2008, ACMA introduced additional restrictions when it renewed GS1 Australia's 4-watt scientific license to enable only existing authorized users to continue with applications while the agency assessed the results of testing (see GS1 Australia Is Optimistic ACMA Will Adopt 4-Watt UHF Power Limit).
GS1 Australia's general manager of standards development, Sue Schmid, says the decision to now lift the restriction on 4-watt UHF RFID systems removes a barrier to adoption of UHF RFID, which is more robust and performs better as the power output is increased.
Schmid says RFID with power up to 1 watt has limitations in terms of read distance.
"Now, companies can use power levels of up to 4 watts in the 920-926 MHz band without authorization and get more read distance, better read rates and more accurate data," she says. "In the supply chain, different companies have different needs, and this change allows business to have more options to meet their needs."
It will also enable companies to improve the efficiency of RFID systems and generate greater return on investment when using UHF RFID in the supply chain, she says.
Schmid says the lifting of restrictions on UHF RFID should increase interest in the technology but says it is unlikely that it will open the floodgates in Australia. Instead, she says in today's business environment, companies will trial the technology internally first for their own benefit. In addition, she says, significant increase in UHF RFID use will likely come when larger businesses start requiring their suppliers to use the technology.
Despite ACMA clearance to use 4 watts of power, GS1 Australia has issued some precautionary guidelines for companies seeking to use RFID devices to prevent potential interference with GSM-based networks. These guidelines include not building within 100 meters of a mobile phone base station, or if that is not possible, to point RFID antennas away from a phone base station and set the power low before gradually increasing to 4 watts
"This is just a case of erring on the side of caution," says Schmid. "Our testing indicated no risk to Vodafone's network, and we ran tests that included pointing 100 RFID readers at a base station. But as we do not know how many readers will be close to mobile phone towers, we provided advice to minimize any potential impact."
The guidelines are not mandatory, but Vodafone detects any interference, the onus is on the company using RFID to turn down the power on its equipment and ensure there are no adverse consequences.
"Not every company will need to turn up their RFID devices to 4 watts," says Schmid. "A retailer detecting items on their shelves does not want a large read range. The guidelines are simply to help companies in the process of using 4 watts of power and determining what they need."
