Vodafone’s new high-speed GPRS network may be hobbled by concerns over radiation levels before consumers even get to use it.
A report in New Scientist magazine says transmission speeds will have to be reduced to avoid exceeding European emission guidelines.
GPRS, general packet radio service, is a so-called 2.5G system that promises theoretical connection speeds of up to 144Kbit/s to the cellphone. Vodafone New Zealand claims to have the world’s first national network ready for GPRS, it just needs “handsets and applications” to be able to offer the service.
But a Motorola marketing manager confirmed to New Scientist that transmission speeds will need to be a great deal less than 144Kbit/s to keep radiation levels to within international standards. “We have known for ages about these limitations,” says Rainer Lischetzki of Motorola. Motorola has since claimed Lischetzki is not qualified to discuss GPRS issues, despite being Motorola’s technical marketing manager for GPRS.
But Vodafone New Zealand’s director of engineering Arthur Neely confirms that such speed restrictions will take place. “I think that’s an accurate comment,” says Neely when asked about transmission being restricted to 20Kbit/s to 30Kbit/s.
“I think the next round will be compression techniques to get it up to 54Kbit/s or 56Kbit/s.”
GPRS is an extension of the GSM network that Vodafone uses here and other telcos use around the world. Telecom is currently piloting the rival technology CDMA. GSM uses channels sliced into eight slots — each running at 9.6Kbit/s. GPRS allows users to access more than one slot at a time, but New Scientist points out that using two slots may cause the phones to overheat and using more than two increases the radiation emission levels beyond European standards.
New Zealand standards for such emissions are similar to Europe’s.
“It’s not an easy thing to measure — you can’t just wave a device by the phone and say this one’s okay, that one’s not,” says National Radiation Laboratory spokesman Martin Gledhill, who refers to an emission’s specific absorption rating or SAR. He says New Zealand's maximum SAR of two watts per kilogram averaged over any 10 grams is consistent with international guidelines. Gledhill says that on first reading the idea that increased bandwidth would also increase the radiation output “makes sense”.
But Ericsson communications manager Alison Crosbie says there is some confusion over the issue.
She claims the first wave of handsets are limited to only two slots and that will restrict the speed to a maximum of 20Kbit/s but the second generation of GPRS handsets, due in July, will allow up to four slots to be used at one time.
“The network would still be 144Kbit/s but the phones wouldn’t work at that speed.”
Crosbie says she has not seen the New Scientist report and cannot comment on it.
Telecom spokesman Glen Sowry says Telecom’s alternative 2.5G network, using CDMA, will initially launch at 14.4Kbit/s and the company will increase speed across the network to 144Kbit/s with an upgrade to take place towards the end of the year.
“The phones are expected to operate near that theoretical limit.” Sowry knows of no concerns over radiation emission levels for CDMA handsets.