4G Networks Tested: WiMAX vs. HSPA+
Jun 4, 2010, 11:01 AM by Rich Brome
A look at 4G and "4G speed" networks currently being deployed in the US; how Sprint's WiMAX technology compares to T-Mobile's HSPA+ technology.
Today, America's first 4G phone goes on sale. We just published our
in-depth review of the HTC EVO 4G, but the other half of the story is the 4G network on which it runs. How does Sprint's shiny new 4G network - which uses WiMAX technology - actually perform?
Also making waves these days is T-Mobile's claim that its new HSPA+ network offers "4G speeds". How accurate is that statement, really?
We set out to answer those questions by conducting extensive testing in Philadelphia, one of the few areas where both technologies are commercially deployed. 4G means a lot of different things for the companies involved, but for consumers, it's basically about data speed; how fast can you load full web sites on your phone or watch Hulu on your laptop? We wanted to see how these fancy new networks stack up where it counts. What we found may surprise you.
Is Sprint's 4G network "up to ten times faster" than 3G, as Sprint claims? Eh... based on our tests, we'd say that's misleading. But Sprint's 4G network does work, and it is fast.
Does T-Mobile's HSPA+ network offer "4G speeds". Yes, absolutely. In fact, despite being an upgrade to existing "3G" technology, we found that T-Mobile's HSPA+ network was often slightly faster than Sprint's "4G" network. By some measures, it's much faster.
That's the problem with the term "4G". There's some confusion about what it means.
To the engineers that create these technologies and decide the standards - like the fine folks at the ITU (International Telecommunication Union) - a technology is only "4G" if it meets a list of criteria. The ITU says "4G" should offer speeds of at least 100 Mbps. No current technology comes close to meeting that requirement, so according to the ITU, what Sprint's offering - and even the LTE technology Verizon is working on - are not true 4G.
But try telling that to Sprint and Verizon, whose marketing departments have clearly decided that their big new networks are "4G". It's not purely marketing spin, though; there is some sense to it. Sprint and Verizon are building these 4G networks from scratch, not upgrading their 3G networks. That's because Sprint's WiMAX - and Verizon's LTE - are all-new technologies that have very little in common with 3G. These new technologies are more modern and more data-centric. Because it's a whole new generation of technology, more advanced than the existing 3G (3rd-generation) technology, it makes sense to call it 4th generation, or 4G.
T-Mobile's story is different. They're taking the existing WCDMA/HSDPA 3G network and upgrading it to HSPA+ technology. It's still technically considered 3G technology by most, but on the most important spec - data speed - it's just as fast as the other networks' 4G, making it very much a viable competitor, regardless of what "G" it is.
In this article, we didn't set out to compare all carriers' data networks head-to-head. Rather, we're focusing only on the new technologies being offered by the two carriers advertising 4G or 4G-like speed. For a comprehensive look at all carriers' 3G networks, PC Magazine just published a good comparison.
We chose six locations around Philadelphia: five downtown, and one in the 'burbs. At each location, we tried each technology, ran three different speed tests, and for each test, used at least three different test servers located in different but nearby cities. These were then averaged to get the speed for that technology and location combination.
If we tried this in a different city, the results might be a bit different, and even just using slightly different locations in Philadelphia would change the overall average a bit. However, having performed well over 300 tests total, in a variety of locations, we feel confident that our results reflect what users should expect.
The bottom line is that Sprint's WiMAX network and T-Mobile's HSPA+ network delivered roughly similar download speeds, just shy of 3 Mbps on average. These are real-world, average speeds, not ideal numbers skewed by a marketing department. 3 Mbps is easily twice as fast as your typical real-world speed with 3G, and faster even than many home DSL connections.
|Tech||Averages||Location||Down (kbps)||Up (kbps)|
In the chart above, locations A-E are in downtown Philadelphia. Location F is out in Northeast Philadelphia; the suburbs, basically. Location F is worth noting for a couple of reasons.
First, location F is where we saw the worst WiMAX performance. We didn't do enough testing in the 'burbs to say definitively that WiMAX coverage in suburbs is poor, but it says something that we couldn't find a spot with signal that weak downtown. We weren't surprised to see worse coverage in the 'burbs, because Sprint's 4G network is a new network being built essentially from the ground up. Like nearly all networks in the early stages, good coverage starts in a few city centers, then expands and improves over time. Don't let anyone tell you 4G uses the same tower locations as 3G and coverage will be just as good. That's far from accurate. Of course, Sprint's goal is good 4G coverage, so definitely expect the situation in the suburbs to improve over time, but it will be a while before 4G coverage matches that of any current 3G network.
In the meantime, we really wish Sprint had a better 4G coverage tool on their web site. Sprint's current coverage map is nearly useless, showing vast areas simply as "covered", rather than making a distinction between good and poor signal. The difference can be vast, as our tests show. Therefore be sure to ask people in the area or take advantage of a trial period before assuming 4G coverage will be good where you need it. That's good advice for any wireless service, but in weak areas, 4G can be slower than 3G, so it's especially important in this case.
Just as Sprint is still building its WiMAX network city-by-city, T-Mobile is still in the process of upgrading its network to HSPA+, also city-by-city. Once a city has been upgraded, T-Mobile's HSPA+ coverage is the same as their existing 3G network coverage, since it's the same network, just upgraded.
The second reason location F is notable is that it's within a special area of T-Mobile's network that they use as a testbed of sorts for 3G technology. This is where they try new tower technology before deploying it nationwide, so it's a kind of showcase for what HSPA+ can do. Indeed, we saw impressive speeds there.
We also compared WiMAX and HSPA+ against 3G technologies.
Both were considerably faster than CDMA EVDO Rev. A, the 3G technology deployed by Sprint and Verizon. In Sprint's case, that's pretty easy, since - at least in Philadelphia - Sprint's 3G network is dismally slow: half the speed of Verizon's 3G network, which uses the same technology. But even if you're switching from Verizon 3G, you'll get noticeably higher speeds with either WiMAX or HSPA+, at least in good coverage areas.
One curious data point was comparing T-Mobile's HSPA+ with their own HSPA 7.2 (slightly older 3G) technology. If you just look at the theoretical peak numbers - 7.2 vs. 21 Mbps - you might think HSPA+ is almost three times faster than HSDPA 7.2. You'd be wrong. We compared them extensively, in all six locations. In our tests, the difference was small. At best, our webConnect Rocket USB stick with HSPA+ was only 15% faster than a standard webConnect USB stick with HSPA 7.2.
On the flip side, that means HSPA 7.2 devices deliver surprisingly fast data on T-Mobile's upgraded network. That's significant because T-Mobile offers a good selection of phones with HSPA 7.2, not just data devices for laptops.
So far, we've only talked about download speed, and that is the most important number. However there's also the upload side of the connection, which becomes important when uploading a photo to Facebook, sending a video message, or sending email with an attachment, for example. It also impacts the quality of a video chat. On that front, T-Mobile's HSPA+ is more than twice as fast as WiMAX. Most users care more about download speed, but for some users, the faster upload speed may tip the scales in favor of HSPA+.
Curiously, Sprint told us that upload speeds are currently capped on their WiMAX network, meaning the network is fully capable of faster upload speeds, but they've opted to set a speed limit at something slower. We're not sure why they would do that, but if that's the case, it explains the relatively slow upload speeds we saw. It also opens up the possibility that they could lift the cap in the future, allowing faster uploads. But until then, our tests show what users should expect now.
In addition to download and upload speed, another meaningful number is latency. This could be described as the delay before a download or upload starts. For downloading a large file, it's not very important, but for interactive things that are supposed to be real-time, it's crucial. On this test, T-Mobile's HSPA+ was, again, twice as fast. The difference was one-tenth of a second, so it's not something you'll notice in typical web browsing, but it would definitely impact applications like multi-player gaming and video chat.
One last fact we learned while talking to Sprint about their WiMAX network is that parts of their Philadelphia network are already at capacity, meaning the network is "full" with existing users and, essentially, maxed out. Part of the reason is that the very same network is also being marketed under the Clear and Comcast brands, and both are advertising heavily here in Philadelphia. It's not a huge problem, though, because Sprint and its network partners own a boatload of currently-unused radio spectrum that they can use to add new capacity. That's exactly what they're in the process of doing, making this a temporary problem.
On the Sprint side, we tried an Overdrive Wi-Fi mobile hotspot and a U301 USB stick. We tested the two head-to-head in a number of locations to see if there was a speed difference. There wasn't. Therefore our Sprint testing was conducted using the Overdrive (with 1.06 software.)
For T-Mobile, we tried both the "webConnect" USB stick (HSPA 7.2) and the faster "webConnect Rocket" USB stick, with HSPA+. Both are made by Huawei. As we mentioned earlier, we tested them extensively head-to-head and were surprised that the speed difference was only about 15%.
When it comes to user experience, all of these devices were terrible.
All of the USB sticks required special software to work on our Windows 7 laptop. The software for each was buggy, difficult to set up, confusing to use, and slow to start and stop the connection. It's something you get used to, but it just seems unnecessarily frustrating.
The gold standard in our book is the Novatel MiFi - available for Sprint and Verizon 3G networks - that connects to the PC via standard WiFi. It's tiny, lightweight, turns on and off quickly, requires no software, is dead-simple to use and is completely wireless.
That's why we had high hopes for Sprint's Overdrive. Like the MiFi, it's a mobile hotspot that connects to your laptop over WiFi. It does indeed work, and it's nice that it requires no clumsy software or time-consuming connect/disconnect routine on your laptop. Even if you connect it to your laptop via USB instead of WiFi, it works with no extra software, using the modem function built into the laptop's OS. (Why oh why don't the USB sticks work that way?!) Even the initial setup process requires no software and works over Wi-Fi.
Unfortunately, the Overdrive is large, takes an eternity to start up and shut down, crashed on me a few times (requiring a paper clip to reset) and has a bad user interface.
The Overdrive has a relatively large color display, which is quite unusual for a modem. In theory, that should make it a breeze to use; unfortunately, it's completely wasted. We were frustrated that the display has tiny, cryptic icons that require the hard-to-find electronic user manual to figure out. For a while it was flashing an exclamation point icon at us. It took us a while to figure out what that meant. It's baffling why it wouldn't simply show a plain-English alert message; there's plenty of room for it on that display. They could have made the Overdrive smaller and much easier to use by replacing the display with a handful of LEDs and buttons.
We hope that the next version of the Overdrive is smaller, faster, and easier to use.
As for T-Mobile, they don't offer a mobile Wi-Fi hotspot product at the moment. We hope that changes soon. Huawei - the company that makes T-Mobile's current USB sticks - does make HSPA+ mobile Wi-Fi hotpsots. We checked one out at MWC in Barcelona this past February. Here's what the Huawei E5 II looks like, and how it compares to the MiFi:
Huawei E5 II
Click a thumbnail above for a larger view.
This specific version is for European 3G frequency bands, but we're sure Huawei would be happy to make a version compatible with T-Mobile's HSPA+ network. C'mon, T-Mobile, make it happen!
T-Mobile HSPA+ Home Router
We managed to get our hands on an unannounced T-Mobile USA HSPA+ device. It's a WiFi router, like Sprint's Overdrive, although it lacks a battery, so it's designed to stay at home and replace a wired broadband connection like DSL or cable. In addition to WiFi, it sports an Ethernet jack for connecting a wired home network, if you wish.
The device came from a contact involved in a closed market trial. Our contact wasn't told the objective of the trial, just to take the device and give it a spin.
Therefore, we honestly don't know much about it, except that it exists. We don't know whether they plan to bring it to market, or if it's just intended for trials. (Occasionally devices are manufactured just for trials, such as the Samsung Digital TV phone announced at CES in January.)
We tested it out briefly. It worked fine, although in our tests, it delivered speeds similar to our webConnect HSPA 7.2 USB stick.
The bottom line is that 4G is here, and it works. Both T-Mobile and Sprint offer impressive speeds that will let you browse the web faster than ever. We watched a bit of Hulu during most of our testing, and it looked impressively good with both technologies.
Sprint's WiMAX network is still growing, so you need to check coverage carefully before banking on it, but if Sprint offers good 4G coverage where you need it, it's at least twice as fast as 3G on the download side.
If you're shopping for fast data, though, T-Mobile's upgraded HSPA+ network is worth a hard look. HSPA+ is just as fast as WiMAX for downloads, and much faster when it comes to upload and latency. That means T-Mobile might be the better choice if you need to upload a lot of videos or do some serious multiplayer gaming. T-Mobile plans to have 100 major metro areas upgraded to HSPA+ by the end of 2010.
When it comes to phones, Sprint offers just one 4G model: the HTC EVO 4G. T-Mobile, however, offers nine models with HSPA 7.2 at the moment. HSPA 7.2 clocked impressive speeds in our tests, definitely comparable to Sprint's 4G.
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