Road test: Does WiMax work in the real world?

Performance is good when you're sitting in an office or cafe, but don't count on connecting from a moving train or car

Just a couple short years ago, many people were abuzz over metro Wi-Fi experiments in Philadelphia, Houston, and San Francisco, only to see those efforts largely collapse as slow speeds, expensive deployments, and economic tussles between carriers and municipalities resulted in low adoption. But waiting in the wings for several years has been the promise of WiMax technology to deliver broadband connectivity wirelessly across entire cities with less equipment to deploy than metro Wi-Fi. After nearly two years of uncertainty, Sprint and its partner Clearwire are now starting to set up WiMax networks in several cities.

WiMax promises users a wireless connection that rivals wired DSL or cable links in speed and reliability. Does it actually deliver on those claims? To find out, I tested the Clearwire Mobile High Speed Internet service for about a month in one of the first deployment areas: Reno, Nev. The results were mixed: The WiMax service provided good connectivity and performance when I was working in a fixed location, whether at my home office or at a café. But I could not get it to work when I was on the move, such as when being driven in a car. (To be completely accurate, the Clearwire service is not officially WiMax but OFDM, the underlying technology behind the WiMax standard. Clearwire deployed the Reno network before the WiMax standard was final, but it is practically the same technology.)

[ WiMax  is in for a fight with 4G cellular networks. See "The looming battle over wireless broadband." ]

Setup was straightforward: Run the installation CD and pop the PC Card into your laptop. I did have an issue with my company laptop because of security measures that disabled installation of unapproved applications, but that had nothing to do with the Clearwire product. If you're considering equipping your laptop users with Sprint or Clearwire WiMax service, be sure to work out the security issues on a test system first. Although Clearwire tried to help, the issue was beyond its scope, and the corporate security staff also couldn't figure out how to authorize the service on my company-issued laptop. The service installed with no problem on a personal laptop that didn't have such security measures applied to it.

WiMax performance is decent but not always consistent
With the software and PC Card installed on that personal laptop, I was good to go. The network connection established itself right after I inserted the PC Card. I was now able to connect wirelessly pretty much everywhere in Reno. A nice touch was that when you start up the PC, the Clearwire software lets you choose between connecting via WiMax or Wi-Fi; Wi-Fi is typically faster when it's available.

To see if the WiMax service truly met broadband speeds, I took speed tests throughout the day from my home office. I got consistent performance much of the time, with download speeds between 1.5Mbps and 2.0Mbps, and upload speeds between 275Kbps and 325Kbps. Sometimes, speeds dropped to less than 1Mbps down and 125Kbps up, but not for long, so they didn't affect my use. It's not clear what caused these occasional slowdowns, and they occurred both when the laptop was stationary and when it was in motion.

Location mattered somewhat in terms of performance. At Walden's Coffee Shop, a local café in west Reno, the Clearwire service came up quickly and worked well. At a medical office complex in southwest Reno, the service also worked well. In a shopping mall in central Reno, the Clearwire service came up readily, but its performance was quite a bit slower than most other locations. This might have been due to the heavy steel construction and high volume of electronic "noise" in the area -- both of which can interfere with WiMax signals. Network performance was fine, even though transmission speeds were a bit slower. At another building with significant steel and electronic noise -- a casino where those slot machines can be a nuisance -- the Clearwire service came up quickly and performed adequately for e-mail and other typical business usage, about the same as at my home office.

At their best, the Clearwire WiMax speeds compare to the landline broadband speeds I have gotten with DSL and cable modem services. However, the DSL and cable speeds are more consistent. Plus, cable service is much faster outside of peak hours. (As more folks in an area access the cable service, such as in the evening, the bandwidth for each user is reduced.)

The WiMax speeds are slower than what I get through my home office's 802.11g wireless network, but comparable to the Wi-Fi speeds I get at public hotspots such as T-Mobile's service at Starbucks. I can't compare the Clearwire WiMax service against 3G cellular broadband offerings from carriers such as Sprint and Verizon, since I don’t have such 3G service. But usage of various 3G networks on handhelds by InfoWorld's Tom Yager show that at best -- on the most modern networks -- you get between 700Kbps and 1Mbps connections, and at worst -- on the older networks -- you get less than 300Kbps.

I took the laptop PC to several locations around the Reno/Sparks area and found only one location where the WiMax service was not available: the Caughlin Ranch area in west Reno. I could not get a connection even when I attached the Clearwire antenna (which is supposed to increase signal strength) to the PC Card.

I did test the antenna several times in numerous locations and could not discern any difference in signal strength or performance whether the antenna was attached or not.

Overall, the performance was fine for business uses such as working with e-mail, file attachments, and Web sites. The speed was not sufficient for bandwidth-hungry tasks such as downloading large video files or trying to play high-end games -- but no wireless services support those uses today.

Quirks and quibbles
While I liked the Clearwire WiMax service overall -- I could get good connections most of the time -- I did uncover a few quirks. None of them would be showstoppers, but they could be a nuisance. 

The first quirk was that the Clearwire connection did not always reactivate after I woke up the laptop from sleep. This occurred both when I had moved the laptop from one location to another and when it remained in the same place. Fortunately, it only took a click on the icon in the lower toolbar to reinstate the connection. A related quirk was that the network connection sometimes took a long time to re-establish itself after waking up or restarting the laptop -- as long as 60 seconds. I didn't see a pattern as to why the time to re-establish a connection varied so much.

My second quibble was that connection times varied based on location. In some cases, the network started right up as the laptop finished its initialization processes. In other cases, the PC Card took quite a while to find the network service -- though never more than a couple of minutes or so.

Although WiMax is often thought of as a mobile broadband service, it's really a portable broadband service meant to be used while a device is stationary. The convenience is being able to take that device and use it in different locations, all with the same broadband service. The Clearwire WiMax service scored well on that count.

But it did not work in a truly mobile context: I tried to get a connection while traveling in the car in Reno and in Sacramento and could not connect to the network. That will limit WiMax's utility in trains, buses, and other commuter contexts.

Finally, I was reminded that WiMax's range -- though much, much greater than the range of Wi-Fi hotspots -- is, in fact, limited. I was in Sonoma County, Calif. -- about 240 miles from Reno -- and fired up my laptop. There's no Clearwire WiMax service there, so I had no connection. I had grown accustomed to being able to use the laptop pretty much anywhere in Reno, and suddenly being disconnected was a jolt. That issue will hobble adoption among many business travelers, who will likely consider 3G services that are more widely available or stick with Wi-Fi hotspots that are less convenient but also more predictable. Perhaps Sprint could offer 3G and WiMax as a bundle, so you're covered most broadly with one service and one PC Card.

Still, my test of the Clearwire WiMax service does demonstrate that it is a viable alternative to other broadband services -- where it's available -- for typical business usage. If your main use is for video downloads and 3D gaming, that's another story.


Copyright © 2008 IDG Communications, Inc.