Evaluating how well a mobile device works across different mobile networks is difficult. First, there's the characteristics of the phone itself, added to the technology type of the carrier, whether a GSM/UMTS network like AT&T or the CDMA EV-DO 3G mobile networks of Verizon and Sprint.
On top of that, each carrier's network strength, usability and reliability depends upon tower placements and the backhaul networks that connect them, making some spots or even regions better on one carrier than another, independent of the conditions of another nearby spot or region across the country.
We didn't test the strength of radio connectivity between phones and towers, which is reflected in the "bars" of service reported by a phone. Instead, we measured actual data throughput, providing a better indication of how well the iPhone will actually work on each carrier when you look up maps, browse the web or make Siri requests.
Evaluating carrier claims
Carriers are often very secretive about their networks, hoping to avoid disclosure of any competitive disadvantages. On the other hand, they're very open about any competitive advantages they hold. AT&T advertises the nation's fastest 3G network, while Verizon claims the best coverage and Sprint trumpets its status as the last US iPhone carrier offering an all you can eat data plan.
AppleInsider has been evaluating the three carrier's networks in a series of West Coast tests that seem to have provided fairly conclusive results on what users can expect from each network. The tests of three iPhones on each carrier were performed in parallel across urban areas of San Francisco, Los Angeles, Sacramento and Reno, Nevada, with some rural testing performed between those locations.
The tests we performed won't tell you what level of data service you can expect in any specific region across the US on each of the three carriers. Each provider has strong and weak spots related to their national build outs. Each also has technical pros and cons, divergent plans for the future of their networks, and differing policies for supporting data throughput.
However, while our tests were confined to a limited area of the US, the tests do provide pretty clear results that seem to represent the findings of other users and the reports of other mobile data tests, indicating they are representative of the carriers' own policies that have influenced how their nationwide networks are configured and operated.
On page 2 of 3: AT&T is indeed the fastest phone network, Verizon coverage is indeed more widely available.
AT&T is indeed the fastest phone network
Apple's originally exclusive iPhone partner, AT&T, is clearly the fastest US mobile network. That's largely due to the fact that AT&T's GSM/UMTS network takes advantage of the iPhone's ability to support AT&T's newest UMTS network technologies: High-Speed Uplink Packet Access Category 6 (supporting data uploads of up to 5.76 Mbps on iPhone 4 and 4S), and High-Speed Downlink Packet Access Release 5 (enabling data downloads of up to 14.2 Mbps on the iPhone 4S or up to 7.2 on the iPhone 4 and 3GS).
AT&T doesn't come close to saturating the iPhone's data capabilities; the best download we observed in testing was 5.4 Mbps, and the best upload was 1.2 Mbps. But those speeds are comfortably fast, comparable to accessing WiFi from a mobile device. For data downloads, AT&T's top speed was more than twice as fast as the best scores obtained on Sprint or Verizon, although AT&T's fastest uploads were largely comparable with the best uploads found on Sprint or Verizon.
Whether you're using Maps or Siri or watching videos, AT&T provides hands down faster experiences, at least when you have good service. Whenever you don't have AT&T's best service coverage, speeds drop considerably, even falling to zero in some places. However, on average across all the tests performed in parallel in both rural and urban settings across California, AT&T averaged 1.623 Mbps down and 0.764 Mbps up, numbers than were more than twice as fast overall compared to Verizon's downloads (averaging 0.724 Mbps) and 2.9 times as fast as Sprint's download average (0.559 Mbps).
In terms of upload speeds, AT&T's average was about a third faster than Verizon's average upload speed of 0.557 Mbps, and 1.8 times faster than Sprint's, which clocked in at 0.422 Mbps. If you want the fastest mobile service for your iPhone, AT&T is the clear winner, even when you figure in areas of weaker coverage.
AT&T also has the greatest potential for building on its 3G speed lead for iPhone users. Verizon and Sprint are tied to CDMA EV-DO for their 3G service, and those networks can't get much faster (although they could be make more reliable, potentially raising their average speeds closer to the technology's theoretical maximum of 3.1 Mbps down and 1.8 Mbps up).
AT&T is already delivering download speeds quite a bit faster than EV-DO is capable of ever achieving. On top of that, AT&T's network and the iPhone 4S are capable of even faster speeds up towards the theoretical 14.4 Mbps, something that Sprint and Verizon simply can't achieve with their existing 3G networks. That's why both Verizon and Sprint are working to build out LTE networks capable of faster speeds (although those networks won't ever benefit existing iPhone users unless they begin using an external MiFi wireless LTE device to relay WiFi data service).
Bottom line: AT&T is already fastest in general, significantly faster on average, and has far more room to grow in progressively rolling out even faster speeds to existing iPhone users over the next couple years.
Verizon coverage is indeed more widely available
Neither the average speed of AT&T's network nor its fastest peaks will matter to you, however, if you routinely want your iPhone to work in areas where AT&T delivers poor coverage. For example, we found specific locations where an AT&T iPhone simply wouldn't ring or get any service: at home, in most of the mezzanine level of the San Francisco Muni Metro, in parts of the forest headed to Lake Tahoe, and in the shadowed valley of Los Angeles' Runyon Canyon Park.
There are plenty of areas where mobile phones of all types fail to find service, but both AT&T and Sprint seemed more likely to lose coverage in certain dubious fringe areas than our Verizon test phone. Even in areas where one might expect not to have data coverage (such as in an underground metro station) the Verizon iPhone could often find enough service to remain marginally usable. These cases provide reasons why you might opt for slower overall coverage in order to have at least minimally functional service more of the time.
Having switched to Verizon in San Francisco earlier this year (as soon as the Verizon iPhone 4 became available), I have to report far fewer occasions where I discovered having no service at all, compared to AT&T. However, Verizon's data service is noticeably slower (particularly evident when loading maps) and belying its heavily promoted "better 3G coverage" rhetoric it seems to drop from 3G EVDO to "o" service (apparently 2G CDMA2000 1x, which feels significantly slower than AT&T's EDGE) surprisingly often. Driving across the country this summer I noticed Verizon losing service completely in some rural areas. Overall however, Verizon has demonstrated functional service in more areas than AT&T, 3G or not.
The decision to pick Verizon over AT&T therefore depends upon how much of your mobile experience occurs in areas with reliable AT&T's coverage. If you travel through lots of rural areas or know of poor coverage by AT&T in or around your home, office or school, you might likely be better off with Verizon's slower but in many cases more dependable service coverage.
At the same time, AT&T is incrementally improving its coverage map. Additionally, Apple's new iMessage and FaceTime capabilities means that you can now contact people and receive texts from other iOS 5 users even if you don't have good mobile service, if you are located somewhere that WiFi is available. Previously, if you didn't have mobile coverage, you couldn't send or receive any texts at all. That makes WiFi availability a secondary consideration when deciding whether to opt for AT&T's faster coverage or Verizon's often better coverage at slower data rates.
On page3 of 3: Sprint is indeed the only unlimited iPhone data contract still available, US iPhone carrier overview.
Sprint is indeed the only unlimited iPhone data contract still available
And then there's Sprint. As the newest iPhone carrier in the US, Sprint is also the last to still offer an unlimited data contract. The problem, at least right now, is that Sprint's data service is so bad it's unlikely you could ever get your money's worth of data using a Sprint iPhone. While neither Sprint nor Apple have really addressed the issue directly, there seems to be something tragically wrong with how the iPhone works on Sprint's network. If it's not something unique to Sprint, it would be hard to imagine how Sprint has remained in business this long.
We briefly compared Sprint's iPhone service to an Android HTC EVO 4G phone, and found better data throughput on the EVO in the same location, even when confined to working on the 3G network. Sprint has been selling the EVO for much longer, so it appears to have worked out more kinks that have not yet been resolved for the new iPhone. Until Sprint solves its iPhone service issues, it would be frustrating to try to use Sprint as an iPhone service provider.
Sprint served the slowest data by far, and we found "no service" problems more often on Sprint's network than AT&T. Even at times when the Sprint iPhone was able to complete a data test, it often wouldn't work well enough to bring up a map, check email, or respond to Siri requests. Given how frustratingly bad Sprint's 3G network was in practice, it seems very likely that there must be a fix in the works to solve the iPhone's terrible performance on its new carrier. That wouldn't be unprecedented, as Apple has consistently released updates that have aimed at improving how well the device works on specific carriers.
At this time however, it's extremely hard to recommend the Sprint iPhone, unless the problems we saw were unique only to San Francisco, Sacramento, Los Angeles, Reno, Nevada, and various points in between. Judging from online service complaints, it appears Sprint's network needs additional work to properly support the iPhone.
US iPhone carrier overview
While our tests averaged in poor results obtained in each carrier's "service holes" that we discovered while performing tests at scores of locations throughout California, the tests weren't intended to capitalize on areas of known poor service. For example, we didn't purposely conduct a series of tests in metro stations or in other areas where most carriers seem to lack decent service, such as within the bowels of San Francisco General Hospital or deep in the middle of the forests around Lake Tahoe.
We tried to incorporate a variety of test locations that reflected where users might expect to actually use their phone: in the car on the freeway in both urban and some rural settings, walking downtown, in urban parks and in residential neighborhoods. The results seemed very consistent: AT&T regularly delivered significantly faster speeds, although it was not always the winner and occasionally failed to find service. Verizon seemed to deliver moderately good service at slower overall speeds, but often continued to work after AT&T and Sprint began to fail due to being in a difficult topography or further from civilization. Sprint was just flat out abysmal overall, although it did occasionally deliver top speeds rivaling Verizon.
It's also important to consider that the data speeds you enjoy will be influenced by the demand around you. For example, we observed download data speeds of 2.0 to 3.9 Mbps on AT&Ts network at LA's Hollywood Bowl when we initially arrived for a show, but after the concert venue filled up, data service plummeted to a nearly unusable 0.18 to 0.27 Mbps during the show's intermission, when the entire area was saturated with smartphone users trying to post photos on Facebook.
At the same location, Verizon initially provided downloads that peaked at 1.1 Mbps, but which similarly plunged below 0.150 once the venue filled up. Sprint's service there was at best reaching 0.660 to 0.730 Mbps before many had arrived, but similarly dropped into a virtually unusable state, reporting data throughput of just 0.022 Mbps once the area was full.
The idea that AT&T is a terrible service provider and certainly the worst in the US (and in particular in San Francisco), was flatly refuted in our testing. AT&T not only won overall in speed tests by a wide margin, but also delivered the fastest peak scores by far. The carrier also trounced its competitors within the average scores tallied in San Francisco and in LA, and even beat both Verizon and Sprint in rural tests between San Francisco, Sacramento and Reno Nevada.
Examining the data scores we achieved on each carrier (compiled by the independent third party Speedtest.net app, which rates bandwidth by sending bits back and forth to its servers) further notes that AT&T's throughput only dipped below 0.500 Mbps in 17.5 percent of our tests. Verizon dipped below that same threshold in 47.6 percent of our tests, while Sprint delivered scores below that more than half the time, in 55 percent of the tests.
Conversely, AT&T's download results were better than 1.5 Mbps in more than half of our tests, 50.8 percent of the time. Verizon only beat that threshold in 11.1 percent of our tests, while Sprint only exceeded it 6.4 percent of the time.
These findings make it even harder to recommend Verizon over AT&T, for anyone other than individuals who happen to live or work in a known AT&T dead zone. AT&T's fatal flaw is that it doesn't cover as much area, so its tremendous speed advantage can become irrelevant when you need to place a call or look up information just as you happen to walk into a dead spot.
Sad prospects for improvement in US mobile networks
The results indicate that AT&T has made significant improvements to its network over the past few years as the iPhone's exclusive carrier in the US, and suggests that the complaints about AT&T as a carrier have been somewhat overblown, just as issues with the iPhone's longevity, antenna design, battery life and other factors have been wildly overstated by its most negative, vocal critics. At the same time, the hope that AT&T might rapidly improve its network by incorporating T-Mobile's resources is looking increasingly less likely as the FCC moves to block the merger on the grounds of competition.
Unfortunately, the FCC isn't bothering to make any efforts to actually compel US mobile carriers to build out better coverage, nor is it doing anything to supply carriers with the bandwidth they need to offer globally competitive service. In the case of AT&T and T-Mobile, the agency is blindly following an agenda that prioritizes the number of national mobile competitors over the sustainability of each of those carriers, apparently unaware that T-Mobile's parent company, Deutsche Telecom, doesn't want to be in the market and won't be spending the billions needed to make T-Mobile a real competitor even if the FCC is successful in preventing AT&T from acquiring its assets.
The result is that the US is constrained by weak networks that can either boast coverage or speed, while even their top speeds pale in comparison to what carriers in other affluent nations offer, often for much less. Sanford Bernstein analyst Robin Bienenstock noted that a primary reason why US networks are so pathetic is because the American government doesn't regulate how carriers build their networks as European nations do, providing the example of rules mandating a minimum number of base stations that, if not achieved, will result in the carriers losing their spectrum allocations.
"Let's take California and Spain as an example, " Bienenstock wrote. "Telefonica has some 33,000 base stations in Spain (yes, miserable, economically imploding Spain). Conveniently, California is a similar size, has a similar topography, and has very similar population density. In California, AT&T has just over 6,000 base stations. The spectrum allocation per pop in these two operators (TEF in Spain and AT&T in California) is remarkably similar. A similar analysis looking at New Jersey and Massachusetts vs the Netherlands shows similar results.
"Why are European networks so much denser than American networks? In large part the answer lies (again) in regulation. In Europe, the spectrum auctions of last decade came with 'use it or lose it clauses' that obliged operators to build a minimum of base stations or face sanctions from fines to loss of spectrum. The result is clear to any American visiting Europe and more frustratingly obvious to any European visiting the States.