February 22, 2012, 10:29 AM — Roughly a year after Verizon Wireless established LTE-based 4G mobile phone and data service in New York City, AT&T's rival LTE network is up and running here and in several other cities. Although its average speeds lagged behind Verizon's in my tests, AT&T's 4G LTE service has a lot going for it.
That's because in a few spots the AT&T network wasn't just fast, it was blazingly fast, with a peak throughput of over 40Mbps. More details on the strengths and weaknesses of each network later. First, let's take a look at the technology.
AT&T's new network is based on the same Long Term Evolution protocol that Verizon's 4G network uses. As the latest upgrade of the Global System for Mobile Communications (GSM), LTE has a theoretical top speed of over 100Mbps.
At the moment, both AT&T and Verizon take advantage of the 700MHz spectrum band that was used for analog TV broadcasts prior to 2008, when it was auctioned off by the FCC. As its LTE rollout proceeds in other cities, AT&T plans to use the 1.7GHz and 2.1GHz bands as well, according to a company representative.
Network availability
So far, AT&T has set up its 4G LTE service in 28 major metropolitan areas, from Boston to San Diego. By comparison, Verizon, which has a year's head start, offers LTE service in nearly 200 cities -- some as small as Dover, Del. -- as well as in 122 airports.
Neither network has much in the way of LTE service in rural areas such as the upper Midwest and plains states, although Verizon recently added Duluth, Minn., to its list. Look for both networks to continue to broaden their reach, but don't expect 4G service in places like West Texas that haven't even gotten 3G service yet.
In the New York metropolitan area, Verizon's network reaches beyond the five boroughs into parts of New Jersey and Connecticut, while AT&T's LTE network is restricted to New York City. In fact, my office, which is a couple miles north of the city border, sometimes has access to AT&T's LTE service, other times not.
Speed tests
To see how these two mobile networks stack up, I ventured in and around New York City for three weeks in January and early February. I had with me two Android smartphones -- an LG Nitro and a Motorola Droid Razr -- which I used to gauge the AT&T and Verizon LTE networks, respectively.
4G confusion
While Verizon was outfitting its cell towers with 4G LTE equipment in 2010 and 2011, AT&T was upgrading its 3G HSPA network to work with evolved high-speed packet access (HSPA+) technology, which brought a speed boost to much of its existing data network.
Like T-Mobile, AT&T refers to its HSPA+ service as 4G, but its theoretical peak download speed of 84Mbps falls short of LTE's 100Mbps theoretical peak. What's more, HSPA+ enhances networks originally built for voice traffic, while LTE networks are built especially for data traffic. Thus, HSPA+ is regarded by many industry watchers (including me) as more akin to 3.5G technology than 4G.
Now AT&T is rolling out its own LTE network, which in my book can more legitimately be called 4G. The problem is that AT&T is still calling its HSPA+ service 4G in ads and in icons on HSPA+ phones. The new service is called 4G LTE -- a difference that may not be obvious to consumers.
To do this, I first loaded Ookla's Speedtest.net app on each phone. At eight separate locations, I took readings for download and upload speeds as well as latency. To eliminate variations due to Internet bottlenecks, I took simultaneous, side-by-side readings for each network. After noting the highs and lows, I averaged all the results.
In some places, AT&T's brand new 4G LTE network was remarkably fast -- for instance, it hit a scorching peak speed of 42.8Mbps in the Wall Street area. That's nearly 50% faster than Verizon's top speed of 28.2Mbps and more than five times what I typically see from a wired cable modem in my office.
