The recent trend
of cities establishing miles-wide WiFi (News
) networks has brought to the forefront important questions about the technologies available to make broadband accessible to mobile workers and other users.
For example: Is it better to use WiFi mesh network, or invest bigger bucks to lay down fiber? Where does WiMAX work best? How concerned should cities be about the evolution of industry standards?
WiFi Mesh Network
The most commonly chosen method to deploy a citywide WiFi network, Settles told TMCnet, is to set up “a bunch of access points that are very similar to the WiFi that you have in your home, except they're access points on steroids.”
For every x number of access points (depending on how the network is used) there is a gateway that aggregates the data and sends it to a major collection point, and then out to the Internet, he explained.
This type of deployment is referred to as a “mesh” network.
Mesh networks are the most common type because they’re low-cost. The fixed access points are relatively cheap, and chips embedded in mobile devices to provide access cost about $5 a pop.
Settles noted that, in a city the size of Seattle
(217 square miles
, greater area population of 3.4 million
), it might cost $10-$15 million to create a mesh network. Cost depends on how the network will be used, and the geography and demographics of the city (building density, number of users, usage peaks, etc.)
Another reason mesh is so popular is that it works very well in city areas, Settles told TMCnet. Physical structures are needed to mount the access points on, and in cities there are plenty of buildings and lamp-posts to fill that need.
But, the more spread-out structures are, the more difficult it gets to create a working mesh network.
WiMAX: Taking WiFi to the Next Level
In areas where there aren't enough structures for regular WiFi, Settles said, WiMAX
is the solution. WiMAX networks also use access points, but these are capable of carrying signals a half mile or more between points.
“You would use WiMAX in a sparsely populated area because you don't have to have as many access points,” he explained.
WiMAX is more expensive, making it cost-prohibitive in many city deployments. That's because WiFi signal doesn't penetrate buildings very well, so in some areas quite a few access points may have to be installed around a building to provide street coverage.
Fiber: Not Wireless, but Worth Mentioning
Any discussion of broadband networks should include a mention of fiber-to-the-home
, Settles said. Usually referred to as FTTH or simply “fiber,” this is high-speed cable buried in the ground that delivers broadband Internet access.
Fiber is very expensive, Settles noted, but it will last essentially forever and will always be fast. It offers the benefits of longevity and speed.
“In the discussion of high speed you talk about fiber versus mesh,” Settles told TMCnet. “With the fiber, you're getting maximum speed and a hedge against obsolescence.”
The downside of fiber is that, because you have to physically dig up grown to lay cable, it costs a lot more. For a city the size of Seattle, it probably would cost $200 million or more to install a fiber network.
Despite the cost, some cities are investing in fiber. Nashville
, Tennessee, for example is looking into this option.
Mesh and Fiber: The Best of Both Worlds (For Now)
If you’re wondering whether mesh and fiber can be combined, the answer is yes.
“The middleground, and what addresses the mobility factor, is using a combination of fiber and mesh,” Settles said.
In typical hybrid network, fiber is used for backhaul
—the outlet to the Internet where all the WiFi gateways dump their data—and mesh is used for the rest of the network.
Fiber is actually cheaper and more reliable for backhaul than WiFi, Settles pointed out.
An example of this type of deployment is Morrow County, Oregon
, which uses two fiber networks strung in from Portland
for backhaul. Fiber goes to some of the city's administrative buildings, while WiFi access points provide mobile access.
“You can have any variation of a hybrid system,” Settles explained.
Returning to the example of a city the size of Seattle, he said a fiber-mesh combo network might cost $25 million.
In a sense, hybrid network provide the best of both worlds when it comes to weighing cost against performance. Settles stressed that hybrids are still a trade-off, though, since fiber ultimately is a better technology for delivering high-speed access.
Bringing WiFi Indoors
Bringing WiFi inside buildings involves what's called customer premises equipment
(CPE)--signal boosters that allow WiFi to penetrate walls. That's how hotspots in malls, for example, are created.
CPE is an affordable and workable way to bring municipal WiFi deployments indoors, Settles said.
In fact, some service providers tapped to create or maintain mesh networks give away CPE as a way to streamline a municipal WiFi deployment. It's easier (and cheaper, in terms of technical support) for all the buildings involved to be using equipment that the service provider knows how to set up and maintain.
Settles stressed that any city setting up a WiFi network would be wise to plan carefully during initial testing and set-up, and also to think ahead to what happens after everything is up and running.
WiFi networks by their very nature will require regular upgrades and other changes as time goes on. For example, as city geography and demographics shift (building go up and down, population numbers change), additional access points may need to be installed and existing ones moved.
Planning carefully, and performing small-scale tests (as Philadelphia
is now doing with its 15-square-mile proof-of-concept network), will allow city governments to predict with a fair amount of accuracy what will be needed to keep the network running once it’s up.
“If you've done your technology due diligence, you get an idea what issues you'll have to deal with,” Settles pointed out.
Compatibility and Standards
It's also very important for cities to consider compatibility issues and industry standards for WiFi technology, Settles said. Vendors should be chosen that support current standards and are taking a proactive stance regarding future changes to technology.
“As long as you're adhering to standards, then changes won't be the kiss of death,” Settles advised.
He also warned that cities shouldn't expect to work with just one vendor, nor should they expect that the primary vendor will stay in that role forever.
Settles advised that any city setting up municipal WiFi should have at least a 3-4 year perspective regarding management of the network. An eye should be kept on the evolution of WiMAX.
If any WiMAX equipment is used now, the city should make sure it's backwards-compatible with WiFi, he added. WiMAX is set to become less expensive as time goes on, increasingly its usefulness in urban settings.
Don’t Forget About the Business Sector
Since it costs money to set up and maintain WiFi networks, Settles advised cities to keep in mind the business sector as an important revenue source.
Business customers are much more willing to pay for services than the average consumer, he noted. WiFi access is especially appealing, since it often offers significant price savings when compared to cellular services.
But, and this is a very important point, if cities hope to tap into this important revenue source, their WiFi networks must be built with the business community in mind.
“If you take that into account, it should impact your network build-out,” Settles stressed.
For example, cities may discover that higher-speed equipment is needed for businesses than ordinary citizens in order to deliver mobile workforce and asset management applications.
The better job cities do at meeting business needs, he noted, the more revenue they'll be able to generate.