Telephone and Data Systems has launched a WiMAX network in Madison, Wis., tapping into the economies of scale generated by Sprint's upcoming Xohm launch. While Sprint has launched trial networks in only two markets, its planned nationwide launch is expected to produce WiMAX devices, modems and infrastructure at the 2.5 GHz frequencies from a plethora of vendors--all of which can be used to fuel WiMAX launches from any carrier owning similar spectrum.

TDS today unveiled a six-tower network built with Alvarion 4Motion Mobile WiMAX gear, a multiple-antenna system that can utilize the same mobile gear that Sprint and Clearwire will support in their upcoming rollouts. Like Sprint and Clearwire, however, TDS is starting off with fixed broadband access, using externally mounted customer premise equipment and desktop gateways to offer broadband data and VoIP service to residential and business customers. The network spans six towers, ringing Madison's outskirts and covering roughly 55,000 homes and 10,000 businesses outside Madison's core downtown Isthmus. But TDS officials said today that as portable and mobile devices become available they would support mobility on the network.

TDS isn't the only operator to hang on Sprint's coat tails. Quad-Cities Online is using Nortel 2.5 GHz gear to launch a fixed wireless and mobile network spanning four towns in Iowa and Illinois, and more small networks are likely to emerge as Sprint's WiMAX rollout gets underway and Clearwire follows suit. There are a lot or rural and regional providers that have 2.5 GHz licenses, and WiMAX will likely be the cheapest way for them to use it. Sprint and the operators that became Verizon Wireless seeded the CDMA market in the U.S. for the hundreds of Tier II and tinier companies that adopted the technology. Now Sprint's doing the same for WiMAX.

TDS may also be able to follow Sprint's example in other ways. TDS owns U.S. Cellular one of the larger Tier II operators in the market. Just as Sprint is using its CDMA footprint to site WiMAX base stations, TDS could do the same with its U.S. Cellular footprint. While Madison is headquartered in Madison, explaining its launch there, it probably didn't hurt that Madison is one of U.S. Cellular's major markets.