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The idea sounds good on paper: Build a mesh network of wireless Wi-Fi base stations and let users roam around an entire city instead of providing limited connectivity in a handful of hotspots. But will it work? The city of Philadelphia hopes so.

"This is an interesting project because it entails building the world's largest mesh Wi-Fi network," said John Krzywicki, president of the Management Network Group, speaking in an interview at the Broadband World Forum in Venice this week. But the consultant warned of challenges facing the venture.

"Even though a similar mesh network is operating in Chaska, Minnesota, that doesn't mean it will work in Philly," Krzywicki says. "The Chaska network is small. The one planned in Philadelphia is much larger, with all the complications of connecting hundreds of users in any given location at the same time."

Earlier this month, the city of Philadelphia announced its plans to invest in a new wireless mesh network based on the current Wi-Fi 802.11b standard.

Widespread Wireless

By deploying Wi-Fi antennas on street lights and other traffic control devises, city officials hope they can turn all 135 square miles of Philadelphia into the world's largest wireless Internet hotspot, the city says on its Web site.

By comparison, the Chaska Wi-Fi network covers around 13 square miles.

Between 8 and 16 Wi-Fi antennas will be needed per square mile in Philadelphia, depending on topography and buildings in the area, the city says. The plan is to connect these units and create a self-organizing and self-healing wireless mesh network.

Once complete, the Wi-Fi network, estimated to cost between $7 million and $10 million, would deliver broadband Internet almost anywhere radio waves can travel, including neighborhoods where high-speed Internet access is currently rare.

City officials aim to complete their plan by early December and invite bids from Internet service providers and equipment suppliers by February of next year.

Krzywicki says he knows of one other large U.S. city planning the construction of a similar mesh Wi-Fi network, but he would not identify it.