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Network World - The phrase "4G network" suggests a seamless blanket of high-speed data connections that are always reliable. Yet the actual deployment of 4G macro cells are highly local and, as a result, there are wide variances in performance and reliability.
At the same time, carriers are experimenting with new data plans for the new 4G networks, adding to the calculus users must perform when trying to figure out if or when the move to 4G is worthwhile.
RootMetrics tests wireless performance in 75 markets every six months. The most recent "Need for Speed" report for the first half of 2012 is online. The data speeds are averaged (across LTE, 3G and 2G connections) for data, voice and texting, and packaged with interactive maps that show coverage and performance by carrier. It lets you compare carrier performance and even drill down to the city block around a home or business.
The RootMetrics' tests show LTE typically delivering average download speeds of 12M to 18Mbps. HSPA+42, being deployed by T-Mobile, averages around 8Mbps. "If you can get LTE, you'll be four to five times faster than you are today on 3G," says Bill Moore, CEO and president of RootMetrics.
In part, that difference between 3G and LTE hinges on the amount of spectrum available in a given area to a particular carrier, but also on LTE's much greater capacity and efficiency compared to 3G. For example, one crippling issue for early smartphone users on 3G data networks was less about the amount of data being sent and more about the amount of signaling traffic generated by the air interface. The signal load unbalanced 3G cells and bogged them down.
"Some of that had to do with the 3G protocol, which has a lot of signaling [overhead] associated with establishing a connection," says Vish Nandlall, CTO and head of strategy in North America for Ericsson, a major supplier of cellular base stations. "LTE is a much more streamlined protocol. There was a lot of foresight in developing LTE in terms of how many messages are passed back and forth to set up a session."
As more users come online with LTE devices, the issue will become network capacity rather than coverage, Nandlall says. LTE has a "huge capacity advantage" at the outset because it's typically using wider channels than 3G, 10MHz compared to 5MHz, he says.
Carriers are creating a distinctive network architecture for their LTE deployments: first, large macrocells for uniform geographic coverage, and then under that umbrella, an array of variously-sized smaller cells to reuse spectrum and increase capacity in local areas. "The small cells will add finer grained capacity between the existing macrocells," says Phil Bull, OSS solutions manager for Amdocs, which sells software and services for carrier billing, CRM and operations support systems.
"If you have a well-planned network, with enough capacity, it will be able to sustain the rates that you've committed to [as a mobile carrier] for a given set of users in a given area," says Eran Eshed, co-founder of Altair Semiconductor, an Israel-based LTE chipmaker.