AT&T Growth Slows
Following T-Mobile's lead, AT&T began branding its wireless broadband service and phones as "4G" this year. And, like T-Mobile, AT&T's HSPA+ service is definitely delivering 4G-like speeds. In our laptop-modem tests, the service produced an average download speed of 2.5 mbps in our 13 testing cities.
AT&T tells customers to expect download speeds of "up to approximately 6 mbps" in "key markets such as Chicago, Houston, and Charlotte [North Carolina]." Although we didn't see many 6-mbps scores in our laptop-modem tests, the network did hit download speeds of more than 2 mbps most of the time (64 percent of the time, to be exact). In fact, AT&T showed average speeds of roughly 2 mbps or greater in all of the 13 cities in which we tested. The network produced its fastest average download speeds in Chicago (3.3 mbps) and San Francisco (3.0 mbps).
AT&T's upload speeds were also strong, and similar to T-Mobile's. Upload speeds in our laptop-modem tests grouped around the 1-mbps mark, with Baltimore hitting a high of almost 1.4 mbps. This is a substantial step up from AT&T's 13-city average upload speed of 0.77 mbps in last year's tests, if not as dramatic an improvement as we saw in AT&T's download speeds.
AT&T's HSPA+ network produced latency times that were very similar to T-Mobile's. We measured an average delay of 169 milliseconds across 13 cities (T-Mobile's average was 173 milliseconds); we saw the highest average latency scores in San Diego (273 milliseconds) and San Jose (226 milliseconds).
Yet the growth of AT&T's data speeds has slowed. Last year we found that AT&T's data speeds had increased 72 percent over the previous eight months. This round, AT&T's speeds continued to grow over the past year, but not as rapidly, and certainly not as swiftly as its competition.
Consequently AT&T finished third in both our laptop and smartphone performance tests. In our laptop-modem results, AT&T trailed T-Mobile only slightly, but showed well less than half the download speed of Verizon LTE.
AT&T's slowing growth was even more apparent in our smartphone tests. In our early-2010 study, we measured a 13-city average download speed of almost 1.3 mbps on our AT&T iPhone 4, an improvement of 54 percent over the previous year. In this year's tests using the same phone, that number moved up to 1.5 mbps, an improvement of only 15 percent.
Some cities were better than others for AT&T smartphones: Chicago saw an average speed of 2.5 mbps while San Diego averaged only 0.8 mbps. Upload speeds improved dramatically, however, as our AT&T smartphone averaged 0.2 mbps in our 2010 tests and improved to just about 1 mbps this year.
AT&T believes that its new 4G smartphones (which weren't available at the time of our testing) and other devices will better utilize the speed of its network. "AT&T has introduced two 4G phones--the Motorola Atrix and the HTC Inspire--and has announced plans for about 20 4G devices this year," the company says in an e-mail. "Regarding network speed, thorough and expansive testing has concluded time and time again that AT&T operates the nation's fastest mobile broadband network."
AT&T's speed increases over the past two years can be attributed to software upgrades and infrastructure improvements. The operator completed a networkwide upgrade to HSPA 7.2 technology in late 2009, then announced earlier this year that it had finished another upgrade to HSPA+ technology, which it says allows for maximum theoretical download speeds up to 14.4 mbps. AT&T also has been investing large amounts of capital in fiber-optic lines for the movement of cellular data to and from the core of its network.
AT&T plans to launch its own 4G LTE network, as well as some 4G LTE smartphones to match, later this year.
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