4G Wireless Speed Test : Which Companies Can Reliably Provide Next-Generation Speed ?

By now you've seen all the ads pitching wireless companies' new 4G mobile broadband services and devices. But beyond all the buzzwords and hype, which companies can reliably provide next-generation speed?

We decided to find out by testing each of the four major national carriers--AT&T, Sprint, T-Mobile, and Verizon--in 260 locations spread among 13 U.S. cities. We found some clear winners and losers, and some good news about wireless service in the United States as a whole. Here are our conclusions.

Wireless data speeds have soared: Since this time last year, the major wireless carriers, as a group, have increased their average download speeds for laptop-modem users by more than threefold, an apparent result of their urgent transition from 3G to 4G network technology.

(We measured the best service we could get--3G or 4G--in each testing location.) Over laptop modems, the Big Four carriers now have a collective average download speed of roughly 3.5 megabits per second in our 13 testing cities, versus a nearly 1-mbps average download speed in those cities at the beginning of 2010, a remarkable improvement.

In our previous wireless-network performance studies, we measured the "reliability" of the data service, expressed as the percentage of tests in which we could obtain a good connection. But our test results show that network service has improved to the point where it's rare to find an unusable signal or no signal at all. So we have retired our reliability measurement--another testament to the dramatic improvements of the past year.

Verizon's 4G LTE is for real: Verizon's 4G LTE service, which is now in 38 U.S. markets, was widely available in 12 of our 13 testing cities. (We didn't go out of our way to test in areas served by Verizon's LTE network; we haven't changed our list of testing cities in the three years we've done these tests.) Our laptop-modem tests on Verizon clocked speeds that were far faster than those on competing 4G networks in the same tests (twice as fast as the second-fastest service, in fact). Verizon's network had an average download speed of roughly 6.5 mbps and an average upload speed of 5.0 mbps.

One important caveat: A relatively small number of Verizon customers currently use this new network. During our testing period, Verizon offered only two laptop-modem models that worked on the network, and none of the company's smartphones could take advantage of the new 4G speeds. The performance of Verizon's network could degrade as more people--and devices--connect to it.

And there's a downside to Verizon's 4G success. While the new 4G LTE network is lightning-fast, our smartphone-based tests suggest that the 3G CDMA network that most Verizon smartphone customers use today may actually be getting slower. The connection speeds we measured on our Verizon (3G CDMA) testing smartphone (a Motorola Droid 2) stayed the same or decreased in 10 of our testing cities since last year. And at the moment, those CDMA phones are all that's available to Verizon Wireless customers.

T-Mobile smartphones are fastest: Verizon may have the fastest network for laptops, but in our tests T-Mobile had the speediest results for smartphones. The T-Mobile HTC G2 we used for testing produced a 13-city average download speed of almost 2.3 mbps; that's about 52 percent faster than the second-fastest phone, Sprint's HTC EVO 4G, which had an average download speed of 1.5 mbps.

T-Mobile also impressed in our laptop-modem tests. Although only half as fast as Verizon's, T-Mobile's download speeds averaged almost 3 mbps in our tests--more than a threefold increase from the carrier's nearly 0.9-mbps average download speed in our January 2010 survey. With these laptop- and smartphone-based results, T-Mobile is proving to be a worthy challenger to its much-larger competitors.

AT&T continues to grow, but perhaps not fast enough: AT&T, the big winner in our January 2010 survey, has continued to ramp up throughput speeds at about the same pace, judging from this year's survey results. Its average download speeds in our laptop-modem tests grew 76 percent to a roughly 2.5 mbps average this year. But each of its competitors showed bigger jumps in download speeds over the past year, resulting in a third-place finish for AT&T in this year's speed results.

And AT&T's speed gains didn't translate well to our smartphone-based tests: The average download speeds we measured on our Apple iPhone 4 (1.4 mbps) increased only 15 percent over the speeds we measured on the same device in early 2010. However, AT&T intends to launch its own 4G LTE network later this year, a move that might tip the balance of the 4G speed race in its favor once again.

Sprint needs more 4G: In the cities where Sprint offers its 4G WiMax service, customers saw large speed increases over the past year. Sprint's average download speeds grew 170 percent to 2.1 mbps in our tests this year; the result would have been even better had the WiMax service been more consistently available throughout our test locations. But in cities such as New Orleans, Phoenix, and San Diego, where Sprint still relies on its 3G CDMA network for data service, download speeds have fallen, and remain well below the 1 mbps mark.