Seamless roaming between WANs and WLANs?

Q. What are your thoughts on seamless roaming between cellular and Wi-Fi hot spots?

What are your thoughts on seamless roaming between cellular and Wi-Fi hot spots? – Janine, Akron, Ohio

The convergence of licensed cellular and unlicensed 802.11 technologies is a question that comes up often. Cellular is a mature wireless voice technology engaged to 3G wireless data; 802.11 is a young, unlicensed wireless data technology. At first glance you might wonder what cellular sees in this immature wireless data service raised in the seedy neighborhood of unlicensed bandwidth. Why stray from your 3G fiancé? Once you get over the differences in family backgrounds of data vs. voice and of being raised on different sides of the licensed vs. unlicensed spectrum, serious arguments can be made for a marriage between the two – or at least a beneficial relationship!

802.11 wireless has some very attractive characteristics. Most notably, it allows a lot of data to be delivered to users quickly and cost effectively, making it a very “cheap date.” Cellular voice networks, on the other hand, were designed to deliver voice traffic, which is very different from data. The average phone call, for example, is less than 5 minutes. Furthermore, 1,000 minutes of voice traffic amasses only about 15M bit/sec of traffic. In comparison, data traffic is measured in hours. Downloading a few PowerPoint presentations would easily blow away an entire month’s worth of voice traffic. So while cellular can satisfy the need for Short Messaging Services, it needs a partner such as 802.11 to satisfy the needs of the mobile Internet surfer.

As with most relationships, there are some issues that need to be overcome. For one, a nationwide coverage footprint is required. As it is unlikely that any single carrier will own and deploy a nationwide 802.11 infrastructure, the need exists for cross-billing agreements and cross-roaming standards between service providers. Second, service providers must address how to deliver quality of service over the unlicensed band and across separate, disparate networks. Several companies are working on resolving these issues, and in my opinion they are solvable.

There is no reason why these issues cannot be ironed out and with the ever-increasing number of 802.11 clients being built into laptops and the emergence of other 802.11 platforms, the pressure is on to make this marriage happen. In my opinion, it is just a matter of time before you start to see handsets and other products with converged 802.11 and cellular technologies.