Software helps carriers add Wi-Fi to mix

Roaming between a wide-area mobile data network and high-speed wireless local area networks (LANs) may get easier to set up after a recent successful demonstration by a Canadian mobile operator.

The carrier, Rogers Communications Inc.’s Rogers AT&T Wireless unit, was able to integrate IEEE 802.11b wireless LANs into a General Packet Radio Service (GPRS) network using software from Mobility Network Systems Inc., according to Naveen Dhar, vice-president of marketing and business development at Mobility, in San Jose, Calif.

The integration allowed Rogers, in Toronto, to use the same user authentication, billing and security systems for both GPRS and wireless LAN services. That means users could go from accessing data on a GPRS network, for example, while walking down the street, to getting that data over a much faster wireless LAN in a public place such as a restaurant or hotel lobby. Charges for both services would appear on a single bill from the carrier. In the trial, designed to test use of the networks for a notebook PC, users did not roam in real-time but turned on the client in each coverage area.

GPRS is a mobile data technology that typically delivers about 35Kbps to 40Kbps and is offered today mostly in specialized mobile phones. IEEE 802.11b wireless, also called Wi-Fi, has a maximum carrying capacity of 11Mbps. It is available today in PC Cards and integrated into some notebook PCs. With a relatively short range, it is intended mostly for offices and public “hot spots.” A more recent technology, 802.11a, can deliver as much as 54Mbps.

Hardware products that can take advantage of both GPRS and Wi-Fi networks are just beginning to emerge. For example, Nokia Corp. makes a PC Card wireless adapter with GPRS, Wi-Fi and High-Speed Circuit-Switched Data (HSCSD) capabilities. Mobility’s software is designed to make it easier for existing carriers to upgrade their back-office systems so they can add wireless LANs to their services.

In the test with Rogers, it took just 24 hours from the first connection attempt to get roaming fully up and running, Dhar said. The test involved hot spots on a campus in Toronto and Rogers’ current commercial GPRS network, he said.

Rogers is already equipped for per-bit billing, because it charges for its current GPRS services based at least in part on the number of bits a customer uses, Dhar said.

In the test, users were authenticated on Wi-Fi networks through the Subscriber Identity Module (SIM), a small card that typically is installed in a Global System for Mobile Communications (GSM) or GPRS cell phone. Using Mobility’s software, carriers could also authenticate customers by other means, such as a user name and password. By using the SIM card method, Mobility demonstrated it could carry off the hardest approach, Dhar said.

As Wi-Fi roaming services are rolled out, software-based authentication methods are likely to predominate because SIM cards require special hardware, can be lost and normally carry a per-card fee from the carrier, said Ken Dulaney, an analyst at Gartner Inc., in Stamford, Conn.

The biggest problem for carriers that want to offer Wi-Fi coverage as part of their wireless service is that none has enough Wi-Fi networks to make the service attractive, Dulaney said.

“If you’re going to sign up for a service, you would probably expect it to be most everywhere you travel…that’s why the monthly plans that include both are of questionable value,” Dulaney said. Service plans that combine Wi-Fi and mobile data probably will start to become valuable in three to five years when carriers can offer access to Wi-Fi in more locations.

The Mobility software has two components, both of which run on standard server platforms. The Radio Access Controller runs at a carrier’s central office, or a carrier can run Mobility’s software on its own server. The Radio Link Manager operates at the site of a Wi-Fi hot spot. The company has implemented the software on Linux and Sun Microsystems Inc. Solaris servers and can port it to other platforms, according to Dhar. The Mobility software will be available in the fourth quarter of this year; pricing is not yet available.