Sony Ericsson helps bridge the Wi-Fi/GSM gap

The GC79 card will let mobile workers connect to GPRS phone networks and to Wi-Fi hot spots, but users will have to wait a little while before they can easily roam between the two

Sony Ericsson is to launch a combined Wi-Fi / GSM PC Card that will help notebook users take advantage of the coverage offered by mobile-phone networks and the higher speed of 802.11b -- or Wi-Fi -- hot spots. Although it will support both types of network, users will have to wait for other bits of the jigsaw puzzle to be put into place before they can seamlessly roam between the networks.

The card, dubbed the GC79, is an update of the existing GC75, which only offers GSM and GPRS connectivity. With the GC79, Sony Ericsson has removed the external antenna. It will support all three GSM bands, for worldwide connectivity, as well as GPRS class 10 and 802.11 Wi-Fi, which provides 11Mbps when in range of a Wi-Fi hot spot. The price, said Sony Ericsson business manager Johan Tysklind, is likely to be about 25 percent higher than for the GC75. Different deals with different network operators make it difficult to name the price, said Tysklind, but estimates hover around 350 euros.

The GC79 will support a relatively new protocol, called Extensible Authentication Protocol, that will let GSM operators bill for Wi-Fi airtime over the GSM network, said Tysklind. EAP SIM, as it is known, should be ratified as a standard this June. Currently, customers of Wi-Fi hot spot operators have to sign up separately and be given a password to use the bandwidth, even when the Wi-Fi service provider is BT. With EAP SIM-enabled devices running on EAP SIM compliant networks, operators will be able to bill for Wi-Fi use through the user's mobile phone bill.

However, the real benefit for many users will be an automatic handover from the GSM network to 801.11b and back, depending on whether they want the cheapest or the fastest available option. "This is not a feature of the card, it's a feature of the software," said Tysklind. "At the moment there are some proprietary applications that enable roaming between GSM and Wi-Fi, but by next year you should see the client software built into Microsoft Windows. That will make roaming much more seemless."

Some trials of GSM/Wi-Fi roaming have already been conducted. Swiss company Togewanet is currently conducting field trials with Swisscom Mobile for its WeRoam services, which lets wireless ISPs connect to the networks of mobile operators and vice versa, so that a common roaming platform can be created.

For a map of the UK's commercial Wi-Fi hot spots, click here.

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