The airwaves in the city of Riverside, California, just got a lot more crowded.
On Monday July 9, the city switched on its municipal wireless network, delivering free internet service to more than three square miles of the downtown area. According to MetroFi, the wireless service provider that teamed up with AT&T to build the network, the ad-supported service offers up to 512-kbps download speeds to each resident in the area covered.
Yet, for many living in the inland empire's capital city, the free service isn't a bonus, it's a burden. The new network adds even more sources of interference to the already crowded wireless spectrum.
MetroFi installed 25 to 30 wireless nodes per square mile to cover the downtown Riverside area. Because wireless signals in the most commonly used Wi-Fi band of 2.4 GHz are scattered by buildings and trees, MetroFi's wireless nodes could interfere with other wireless networks in the area, and vice versa.
Craig Mathias, principal analyst and founder of wireless research firm Farpoint Group, says such citywide Wi-Fi projects could overwhelm nearby residential systems.
"We have definitely seen a negative impact from these systems," he says. "But we just haven't been able to quantify that impact."
Interference on wireless networks will likely get worse before it gets better. Sometimes, the most egregious offenders aren't nearby residential networks or municipal Wi-Fi grids, but the myriad electronic devices in people's homes. Poorly shielded microwave ovens leak radio waves tuned to 2.45 GHz, the resonant frequency of water. Many cordless phones operate in the 2.4-GHz band as well. Wireless keyboards, Bluetooth devices, wireless security cameras and baby monitors can all interfere with a Wi-Fi network.
"It's a worse problem for a consumer than it is for an enterprise, because you have a lot more wireless gizmos in your space," says Neil Diener, chief technology officer for wireless-solutions provider Cognio.
Most people don't notice interference problems unless the cacophony of electronic signals causes their residential network connection to drop. MetroFi, which has covered 77 square miles with wireless networks in the San Francisco Bay Area, has received only five e-mail messages regarding interference problems, the company said.
Diener says the low level of concern is because consumers typically underutilize their wireless networks. For most, wireless is a way to connect to the internet. While even the best residential broadband speeds may reach 5 Mbps, today's wireless network equipment makers boast speeds up to 54 Mbps for popular 802.11g equipment.
If the wireless network can maintain even slight connectivity, Wi-Fi will outperform current broadband solutions, Diener says.
"It's like when your arteries are partially clogged, you don't know it until you have a heart attack," he says.
As consumers push more bits over their wireless networks, the slowdowns will likely become much more obvious.
Apple TV uses next-generation wireless networking technology, dubbed 802.11n, to shuffle multi-gigabyte video files to and from computers on a home network. Cell phones that allow users to browse the internet and even make calls using the local wireless network, such as BlackBerry devices and the iPhone, are increasingly popular. Game consoles like the PlayStation Portable allow players to connect to the internet and each other using Wi-Fi. The next-generation of Wi-Fi has both benefits and drawbacks in terms of interference.
Wireless networks using the most popular protocols, known as 802.11b and 802.11g, use a part of the unlicensed radio spectrum in the 2.4-GHz band by default. The next-generation 802.11n also uses the spectrum by default. While 802.11n access points use multiple antennas to allow the devices to cope with interference and improve range, many consumers will be tempted to use a new feature that doubles the speed of the device -- at the cost of hogging double the amount of spectrum bandwidth.
That's a recipe for greater interference, says Farpoint Group's Mathias.
"That will cream the bandwidth," he says.
While there are a few tricks consumers can try to help deal with interference problems (see sidebar), a solution for the coming flood of Wi-Fi chatter is not yet on the radar.
MetroFi and other service providers already have their hands full making sure interference doesn't impact their own networks, says Chuck Haas, CEO for the Mountain View, California, company. In the company's municipal networks, each node is programmed to dynamically adapt to nearby interference, minimizing its impact on service.
"The ability to deal with interference in the unlicensed band is critical for us," says Haas. "The good news with a lot of this interference is that it is interference with a lot of low-power devices so it might be seen by your neighbor but doesn't affect our outdoor mesh network."
Some consumers -- mostly the tech-savvy ones -- have learned to work around the issue by adding specialized hardware, such as directional antennas, to their networks to improve connections.
"Using a directional antenna that faces away from the noise and toward the users can make a world of difference," says Frank Keeney, the owner of wireless-hardware retailer Pasadena Networks and co-founder of the Southern California Wireless Users Group. "Often the access points are overwhelmed with trash."
However, according to Farpoint Group's Mathias, the real solution has to come from wireless-equipment makers. Until access points and other wireless-networking hardware can adapt in real time to interference in a way similar to MetroFi's municipal network nodes, then wireless chatter will continue to be a problem.
"The good news is there's plenty of spectrum available," Mathias says. "This is not a show stopper. There should be plenty of innovative solutions down the road to fix this problem."