Public-access wireless LAN (WLAN) hotspots are spreading rapidly throughout the UK and Europe, so much so that many people believe they constitute a serious threat to the fledgling high-speed mobile data services provided by mobile operators.
But as the mobile operators seek to turn this threat into an opportunity, it is clear that there is considerable scope for interconnecting the two technologies to provide a seamless roaming experience.
GPRS services are now available on all UK cellular networks, and the building of third-generation (3G) networks is well under way. Consequently, the mobile operators now have IP networks that consist of tens of thousands of points of presence (POPs), or base station sites, spread across the country. No conventional telecoms carrier can claim so wide a reach. And it is easy to link WLAN hotspots to these POPs, assuming, of course, that there is enough bandwidth available.
The Third Generation Partnership Project (3GPP) writes standards for present and future mobile networks, and has been working on methods for doing this. There are two main issues: how to make the physical interconnection and how to handle security, authentication and billing. The work seems to be going well and the standards should soon be issued.
The proposed system is very flexible and the main idea is to use the subscription information contained on the SIM card inside the mobile phone to provide authentication for the hotspot service. This doesn't mean that your notebook PC needs a SIM card holder; the PC would extract the information from your mobile phone via a wireless Bluetooth link. This would be very convenient, especially if roaming agreements with hotspot operators become commonplace. There would be no need to sign up each time; the charges would appear on the standard mobile phone bill.
Manufacturers are getting serious about this as well. Giga Stream, a startup company based in Germany, has just launched its Universal Navigation Switch (UNS), which makes it easy to connect hotspots and other broadband services into mobile networks. In addition, the UNS combines the functionality of several data devices used in mobile networks into one box. Other similar devices are coming from other suppliers.
Meanwhile, the IEEE 802.11i task group is working to improve WLAN security systems - particularly important for hotspots where the operators don't want their systems to be hacked. The IEEE is also busy developing 802.16e and 802.20 mobile broadband standards, through which devices such as the Giga Stream UNS can connect to mobile IP networks.
This idea of trading off data rate for range and mobility has been part of the 3G concept from the very beginning. The original planners did not expect the highest rates to be provided using WLAN technology, but the idea is in accordance with their original vision.
These new developments take us closer to the goal of universal connectivity for voice and broadband data wherever one roams. The data rates available on the move would not be much less than those available from fixed locations.
Let's hope the operators don't spoil it all by setting inappropriate tariffs.
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