Since Avaya, Proxim and Motorola announced the initial results of their research on seamless roaming between 802.11 (WLAN) and 2.5/3G cellular networks earlier this summer, there have been a flurry of announcements of plans to converge cellular and Wi-Fi networks. Case in point: yesterday, Chris Rice, the CTO of SBC (NYSE:SBC), claimed that the carrier's public Wi-Fi hotspots will be used to carry calls from Cingular users by 2006.  The new modus operandi will be for phones to become aware when a WLAN Access Point (AP) is nearby and automatically handoff the call to the Wi-Fi network (what I call the ABC - Always Best Connected - model) 

Rice said that SBC can improve Cingular's cellular coverage by filling in the gaps, relying on Wi-Fi hotspots in places like restaurants, hotel lobbies, coffee houses, etc. to mitigate some of the spectrum demands on the wireless operator.  Achieving this goal might be a challenge from a timeline perspective, as there are quite a few details that still need to be worked out.  For instance the systems that can support the 3G/WLAN seamless roaming entail special client equipment, only working with APs supporting newer technology (e.g. 802.11e, which is the QoS standard that also enables longer battery life, due to the "deep sleep feature").  What about all the older APs that have already been deployed?  Nevertheless, it was interesting to see SBC give a sneak preview about its future Wi-Fi/wireless strategy.