Net Waves: Public Wi-Fi: Is it Good Enough?

While there are ample benefits in the design and configuration of a Wi-Fi network the size of a city -- there's also plenty of room for errors.

February 18, 2005

4 Min Read
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I've tested wireless LAN equipment in metro areas, and it's not easy toprovide widespread mobile access. Large structures, such as high-risebuildings, often get in the way. In addition, Wi-Fi standards were notreally intended for large areas. WiMax, which is slowly becomingavailable, is likely a better fit for covering metropolitan areas.

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System integrators have had problems covering midsize venues, such ashotels and airports, with Wi-Fi service. I travel a lot and takeadvantage of public Wi-Fi access whenever possible. For example,recently I was staying at the Four Seasons Hotel in Philadelphia andmoderating roundtable discussions for one of my clients. My room wastop-notch and the staff service was excellent, but the Wi-Fi coveragewasn't too good from my room. Later that same week, I was in Houstonstaying at a Hyatt, and again Wi-Fi coverage in my room was poor. Thecommonality between these two hotels is that they're large and charge$10 per day for Wi-Fi access.

A few weeks ago, I completed a nine-day, 2,500-mile road trip by carthroughout much of the South Eastern United States while working for oneof my clients. This project had a tighter budget, so I stayedexclusively at Holiday Inn Express hotels. They're relatively small andfairly nice for the money, and they provide free public Wi-Fi servicewith excellent coverage, at least in the eight different hotels where Istayed. I guess the old saying that "you get what you pay for" doesn'tapply to public Wi-Fi!

While on these trips, I (for fun) generally measure the Wi-Fi coveragethroughout as much of the hotel as possible. I'm finding that, usually,the signal strength in hotel lobbies is excellent and the sleeping rooms(at least the ones I've stayed in) have good or poor signal strength. Inother areas such as hallways and elevators, Wi-Fi coverage is generallynon-existent. Synchronizing e-mail and browsing the Web may be good ifyou're lucky, but be ready for dropped calls when using voice-over-Wi-Fiphones when roaming throughout the hotel.I mention these experiences, which are common to my travels, mainly asthe basis to underscore my points about public Wi-Fi service. It's verydifficult to cover the large areas, especially in and around bigbuildings such as hotels and airports. In addition, the Wi-Fi servicecurrently available is not consistent in all places. And how will systemintegrators manage the deployment of Wi-Fi service effectively incitywide areas when it's not being done well for even midsizeestablishments now? This question scares me a bit.

If you're a mobile user or an IT manager outfitting users to takeadvantage of public Wi-Fi, then you definitely want to do the obviousthings like securing the mobile devices with end-to-end encryption suchas VPNs. But don't expect too much in terms of performance. Before goingout and purchasing a truck load of WLAN phones and subscribing tovoice-over-Internet services, consider where you'll be using the publicWi-Fi services and whether coverage patterns will accommodate yourneeds. If you'll be using corporate applications that require continuousconnections with the server, then think about deploying data replicationand wireless middleware solutions to take over if the connection islost.

If you're deploying public wireless LANs, then choose proven equipmentand designs. Be certain to review applicable testimonials and evenperform testing at live, relevant public Wi-Fi sites that include theequipment you're planning to deploy. If relevant sites are notavailable, build prototypes and conduct pilot tests in a limited areawithin your environment before installing the entire network. This isespecially true with larger hotspots. Again, I've seen too many midsizeand large Wi-Fi hotspots have lots of coverage holes and unacceptablesignal strength.

Pay close attention to the RF (radio frequency) aspects of the system.Always complete thorough RF site surveys at installation sites todetermine optimum antenna type and placement. Consider the use ofamplifiers, too, but don't forget to apply for licensing with theapplicable regulatory agency such as the Federal CommunicationsCommission in the United States.

The implementation of Wi-Fi service in a coffee shop is one thing, butcitywide deployment is definitely another. In a Starbucks, you canprobably get by with a single access point installed just about anywherewithin the store. With a citywide deployment, there are many accesspoints and lots of obstacles that can get in the way. A problem is,environments change in ways that impact Wi-Fi coverage. For example,tree leaves come and go throughout the year, presenting a significantchange in radio wave attenuation and corresponding signal strength thatusers encounter.So don't hurry the deployments of these larger networks. Instead, fullyunderstand the technical risks and plan accordingly. Because there arevery few of the bigger public Wi-Fi installations, carefully design thesystem and perform testing to iron out the wrinkles before building alarge body of subscribers. This is undeniably a case where you have tolearn how to walk before you can run!

Jim Geier is the principal of Wireless-Nets Ltd., a consulting firm assisting companies with the implementation of wireless mobile solutions and training. Read more analysis from Jim on his Wireless LAN Blog. Contact him at [email protected].

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