TechHive's Wireless Week: Testing America's networks

AT&T clocks best overall speeds with 3G/4G combo

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TechHive's Wireless Week: Testing America's networks

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When your cool new LTE phone loses touch with your LTE network, the 3G radio inside the phone will immediately connect to the older 3G network for your data service. But 3G is slower, so the downshift needs to be a smooth one—one that doesn’t yank you down to a speed so slow, you can’t continue what you’re doing.

If such a jolt were to happen while you're watching streaming video, your movie might might begin to stutter, playing in fits and starts. It might even stop working altogether.

That’s why a comparison of the major national carriers’ combined 3G and 4G speed is important. The fastest LTE speeds can be easily forgotten if your backup 3G service slows throughput to a trickle.

TechHive benchmarked nationwide wireless speeds throughout March and April, and our 20-city tests show that AT&T’s LTE service and HSPA+ service offer the fastest combination of 4G and 3G for dual-mode smartphones and tablets. AT&T’s LTE service showed average download speeds of 13.15 megabits per second, and average upload speeds of a solid 6.45 mbps across our 20 testing cities.

AT&T got a late start relative to rival Verizon in building its LTE network, but it has moved fast and now reaches a respectable 200 million people with its service. Verizon LTE service is now accessible to 287 million Americans, and is generally more accessible as one travels outward from densely populated urban areas.

The downshift

It’s likely, then, that AT&T devices must downshift to HSPA+ service more often than Verizon devices must downshift to CDMA data service—but when they do, AT&T users don’t see nearly the drop-off in speed that Verizon subscribers experience upon downshift. The average download speed of AT&T’s HSPA+ service was almost 3 mbps in our tests.

The average LTE-to-3G downshift for AT&T customers, from 13.15 mbps to 2.97 mbps, represents a 77 percent drop. The average downshift for Verizon subscribers, from 9.61 mbps down to less than 0.80 mbps, represents a 92 percent drop.

We tested 3G speeds with an iPhone 4S.

It gets uglier with Sprint service. When Sprint customers lose LTE service and fall back to 3G CDMA, their speeds drop by more than 90 percent. And the drop-off starts from a far lower height: Sprint’s average for LTE downloads is only 4.32 mbps. The carrier’s backup CDMA 3G service averaged a mere 0.40 mbps in our tests.

T-Mobile didn’t produce LTE speeds as fast as AT&T’s, but its drop-off of 62 percent from an average 4G download speed of 9.01 mbps to 3.13 mbps was the least of all the carriers.

The new LTE technology is, on average, ten times faster than the 3G service many people are used to, and the carriers are doing their best to upgrade their 3G device-owning customers to new LTE devices, with some success. When we conduct our tests next year, well more than half of U.S. cellular customers will likely have moved over to LTE networks.

For now, however, 3G still matters. A lot. Only a quarter of cellular subscribers use LTE networks today; the rest use 3G.

We evaluated 4G speeds using a Samsung Galaxy Note II, a model that all major carriers sell.

“Despite all of the hype around 4G, the performance of 3G networks remains an important consideration; with most service providers still expanding the coverage and capacity of their 4G LTE networks, 3G is often the dominant technology used by most customers today,” says Dan Hays, US wireless advisory leader at PwC.

“The continued advances in 3G speeds demonstrate that service providers are not standing still there, either; they continue to invest in maintaining and even advancing performance, as 3G networks will continue to be used for many years to come,” Hays notes.

The price of speed

But how much do these combined buckets of speed really cost you?

When you buy a smartphone (or some other mobile Internet device), you buy a data plan too. In the end it’s the voice, text, and data plan that costs you more money, not the phone. Of the services you buy, the data service costs you the most. And there’s no guarantee of the quality of data service you’re going to get.

Our speed tests take some of the mystery out of the question by providing some idea of the real speeds of each service. The following chart demonstrates how much you’re paying for that speed, by equating it with the dollar amount you might pay every month for your phone and service plan.

To come up with these results, we figured the total monthly cost of owning each of the phones in our speed tests—the 16GB iPhone 4S and the 16GB Samsung Galaxy Note II. That total includes the cost of the device, monthly plan charges, and any one-time activation fee the carrier charges. We added up all of these costs over a two-year contract period, and then divided by 24 to get an estimated monthly cost. (Click on the chart for a larger image.)

What it all means

The prices in the chart above aren’t meant to reflect actual data-service costs. It’s the difference in the cost per mbps of the various services that’s meaningful. For a 4G/LTE phone (here, the Samsung Galaxy Note II), you’re likely to get the most bang for your buck from AT&T. You’ll get the most megabytes per second of data throughput at the best price, at $5.27 per megabit per second of throughput.

T-Mobile is less than a dollar behind, and Verizon’s 4G speed prices are only $2 behind AT&T’s. Sprint’s 4G network is by far the most expensive for LTE phones, at about $10 more per megabit of throughput than AT&T’s.

Both AT&T and T-Mobile have 4G HSPA+ as the 4G “fallback” network, meaning that when a smartphone cannot pick up an LTE signal, it will pick up the HSPA+ network instead. That could explain why AT&T and T-Mobile share such a close lead for 4G LTE network speeds: Their secondary, fallback networks provide higher speeds than those of Verizon and Sprint provide.

“[We’re] launching 4G LTE on top of our leading 4G HSPA+ network, which means our customers’ experience will greatly improve,” T-Mobile CTO Neville Ray told TechHive. “Plus, they won’t leave an LTE coverage area and wonder where their 4G speed went, as happens on some competitive networks.”

In our 3G cost analysis, we found larger price gaps between carriers. T-Mobile offered the best price per megabit of throughput when we compared iPhone 4S speeds and plan prices across our four networks, at $22.28 per second of throughput. That’s roughly $7 less than our 3G runner-up, AT&T.

But the gap between T-Mobile and Sprint, which has the priciest speed, is astounding: Sprint’s speeds result in a cost of $157.04, because you’re paying more money for less throughput speed (Sprint’s 3G download speed average is only 0.40 mbps).

Comparison methodology

For each carrier in our comparison, we selected the most cost-effective service plans that offered unlimited phone, texts, and at least 4GB of data per month.

For AT&T, that meant Mobile Share (surprisingly, it is cheaper for a single-device user to sign up for a Mobile Share plan with 6GB of data per month than to sign up for an individual plan with 5GB of data per month). For Sprint, that meant Simply Everything; for Verizon, Share Everything; and for T-Mobile, Simple Choice.

Then we combined the average upload and download speeds that we recorded with our two smartphones on each carrier. For the iPhone 4S, that meant combining the download and upload speeds for just the 3G network. For the Galaxy Note II, that meant looking at 3G and 4G throughputs, since the phones fall back to 3G speeds when they can’t access a 4G signal. Finally, we divided the monthly cost of each phone by the combined throughput per second to figure out the cost per second of throughput.

This story, "AT&T clocks best overall speeds with 3G/4G combo" was originally published by TechHive.

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