The city's experiment to blanket its 135 square miles with wireless high-speed Internet access has been hailed by supporters as one of the most innovative projects in the country. But some experts caution that significant technical and business issues must be hammered out before citywide wireless networks can become a reality.
Large cities such as Philadelphia and San Francisco see wireless broadband technology as a low-cost solution to providing broadband access to low-income residents.
They also believe that these Wi-Fi networks can help them save millions of dollars in operational costs by providing broadband connectivity for public-safety and other agencies within city government. Many believe the networks will help boost economic development by drawing more people to the city.
Philadelphia, which plans to have itsup and running by summer 2006, is the poster child of the municipal wireless movement.
While several smaller cities, such as Chaska, Minn., have deployed citywide Wi-Fi, the technology has not yet been tested in large metropolitan areas. Philadelphia will be the first major city to complete its network. Other large cities, including New York and San Francisco, are also looking to build their own Wi-Fi networks.
While supporters applaud Philadelphia for its vision, some experts warn that deploying Wi-Fi in dense urban areas may not be as easy as it sounds.
"Setting up a citywide network is definitely not as easy as putting up access points all over the place," said Doug Schremp, chief technology officer of , a consulting firm that designs and deploys networks. "There are some technical issues that need to be addressed, and cities really need to look at the operational and business issues that come with building and owning their own network."Building a do-it-yourself network
The idea of municipalities providing broadband service has been for the last couple of years, despite who view city-owned broadband networks as a threat to their businesses.
Some cities areto run fiber-optic lines directly to every home and business, which will increase broadband capacities well beyond those available from cable-modem and DSL service today. But these networks are very expensive to build, and many communities are looking at lower-cost, wireless technology instead.
While it would cost about $2,000 to $3,000 per household to run fiber, wireless can be deployed for about $20 to $25 per household. Philadelphia has about 590,000 households, according to the 2000 Census. Using that number, the city figures it will cost roughly $10 to $15 million to reach every household, according to its business plan.
Wi-Fi uses unlicensed broadcast spectrum, or airwaves, to deliver high-speed Internet access through a series of antennas positioned on telephone poles and other locations. Those antennas, in turn, are connected to the Internet. Depending on its location, each antenna can provide a coverage area with a radius of about 1,000 feet.
The spectrum crunch
Even though a wireless network can be built relatively inexpensively, experts say there are many challenges to providing reliable service.
One of the biggest technical issues that cities face in deploying municipal Wi-Fi is that it can suffer interference from other wireless devices trying to transmit signals in the same channel. Because wireless networks run on unregulated spectrum, many devices can interfere with transmission. For example, microwave ovens, hand-held phones, garage door openers and devices using Bluetooth applications all use the same 2.4MHz frequency used by Wi-Fi networks. What's more, thousands of computer users have installed their own Wi-Fi networks in their homes.
"The 2.4MHz spectrum is already very crowded," said Lindsay Schroth, a senior analyst at The Yankee Group. "When you have a large deployment such as Philadelphia also using that spectrum there's a lot of potential for overcrowding and interference."
Interference is a problem because it can greatly impact performance on the network by causing packets of transmission data to be dropped. The dropped packets have to be retransmitted, error rates increase and the routers that send the packets slow down their transmissions to compensate for the losses.
Cities such as Philadelphia say that they don't believe interference will be a big problem.
"We did a radio-frequency survey and didn't find any showstoppers," said Dianah Neff, chief technology officer for the city of Philadelphia. "We have 430 registered Wi-Fi networks in the city of Philadelphia, and we didn't find any problems with interference."
BTS Partners' Schremp, whose firm has surveyed Boston for a potential Wi-Fi network, says he is surprised to hear that Philadelphia hasn't talked about interference as a potential challenge.
"I know Philadelphia has said they haven't seen any problems with interference," he said. "But in Boston, we see it everywhere. We've got a ton of schools and businesses already using Wi-Fi--MIT, Northeastern, Harvard. We have to be careful if we move forward with this project that a citywide network won't impact them."
Most experts agree that interference is an issue that needs to be considered. But they emphasize that every city and every community is different, and that with proper engineering the network can overcome potential problems, even in urban areas.
One solution to overcrowding and interference problems could be for cities to share spectrum that is already available from other sources. Schremp suggests cities partner with area universities and research institutions that already have widely deployed Wi-Fi networks so that citizens in the surrounding neighborhoods can tap into the networks and share bandwidth.
He said that many institutions in Boston are willing to cooperate on such a project. But once a system has overcome interference problems, the biggest concern is how to handle network abusers, such as spammers, illegal file-swappers and people launching virus attacks.
Security and business challenges
In general, operational issues, such as dealing with network abusers, could become more challenging for cities than the initial task of engineering and deploying a citywide network, Schremp said.
While most wireless products today offer adequate security to help keep viruses and attacks on the network to a minimum, managing day-to-day operations of the network could be daunting for a city that has little experience running one.
"Building the network is the easy part," Schremp said. "Cities also have to find a way to fund the operation of the network. That's the piece many people overlook. If an access point goes out, who will go out at 2 a.m. to climb the light pole to fix it? How much tech support do you give users? These are questions all ISPs and telcos have to face."
Cities also face the challenge of developing viable and sustainable business models. Some cities, such as Philadelphia, plan to sell access to the network on a wholesale basis to Internet service providers, telecommunications companies and nonprofit organizations. ISPs and other providers will handle all billing, marketing, customer service and the at-home equipment needed to pick up the signals.
But wholesale business models are not without risks. For example, the quality of the network infrastructure needs to be solid enough for other service providers to rely on it. And because wireless is relatively inexpensive to install, at some point it will become more economical for service providers leasing the city's infrastructure to build their own Wi-Fi networks.
Then there are cities that would like to provide some or all of the access to their networks for free. For example, San Francisco, which is still in the early stages of developing its plans, would like to provide wireless broadband service for free to all its citizens.
Experts in the industry say that these plans may be a little na?ve.
"The free model is not sustainable," said Amit Paunikar, a software engineer at Nomadix, a maker of wireless access gateway products. "Someone has to pay for the construction and operations of the network. I don't think that a lot of cities get how many issues will come up."
City organizers say they understand that the money will have to come from somewhere. Many cities are cooperating with local businesses and technology companies to provide free access in public places. They plan to use advertising on splash pages and local portals to drive revenue.
San Francisco Mayor Gavin Newsom "really wants us thinking of new ways of doing things," said Chris Vein, senior technology advisor in the office of the mayor of San Francisco. "The goal is to create a service that's free to all citizens. But I don't know yet how we will do that. Some funding could come from partnerships or advertising, or some could from taxes. My job is to figure that out."
To be sure, the challenges of deploying citywide networks have given some cities pause. Earlier this month, a study group in Pittsburgh, Pa., recommended to the city council that the city wait to consider deploying Wi-Fi until officials have studied deployments in other cities.
"Using Wi-Fi to provide broadband to an entire city is still pretty new," said Alex Thomson, a local lawyer who chaired the 25-member committee examining this issue. "Our thinking was, do we really want to be the guinea pig? Philadelphia is getting a lot of great press out of this, but we still have to wait and see if the network really gets built and if it works like they hope it will."