MIT Technology Review

Tuesday, March 13, 2012

The New iPad Could Clog 4G Networks

The tablet's high-resolution screen will make for bulkier downloads and maxed-out data plans.

Those who are lucky enough to acquire a new iPad this Friday, when the latest version of the tablet goes on sale, may find their download speeds slowing over the coming months. They may also run up against the data limits in their wireless contracts.

The new tablet connects to 4G networks that are today only lightly used. If it sells in large numbers, the device will place significant new demands on those networks, experts say, requiring bandwidth to be spread more thinly. The new iPad's "retina" display, capable of playing full 1080p HD video, will likely encourage heavy data usage that will exacerbate that effect. Many users may also get their first taste of what it is like to bump up against the data limits that are now a standard part of wireless contracts.

Demand for the new iPad has been very strong; Apple says all the units it set aside for online preorders are now allocated. Long lines are expected outside stores as customers wait for it to become available on Friday. Buyers can choose to sign a contract with either AT&T or Verizon to provide wireless data to their device over new 4G networks that use LTE technology only now being introduced by carriers worldwide.

"The iPad is definitely going to be a challenge, and it will put a strain on the networks," says Michael Thelander, CEO of Signals Research, a wireless industry research consultancy that spent time late last year driving around testing the capabilities of the latest wireless data networks.

Any wireless network has only a fixed amount of bandwidth to share among its users. That means the download speeds that LTE networks can offer users—often between 10 and 20 megabits per second today—will decline. "As more and more users come on, it can't give out bandwidth forever," says Thelander. "I expect the [new] iPad to add congestion."

4G networks are relatively empty today, he says, and the devices using them are not as numerous or data-intensive as the iPad is likely to be. Laptop modems used by business travelers are the most established category of 4G devices today, says Thelander, while 4G smart phones are becoming more popular with consumers but do not use much bandwidth because phone screens are small. "The iPad's right in the middle," he says. "It will have a really strong adoption but also consume large amounts of data."

Thelander doesn't expect problems as serious as those that brought AT&T's network to its knees in some places when the first 3G iPhone was introduced. That experience taught many lessons that have shaped the rollout of LTE networks, which use fundamentally more robust and efficient technology, he says.

LTE networks are still being expanded and are far from reaching their maximum capacity, he adds, although in a recent FCC filing, Verizon said that it would struggle to meet demand for 4G data by "2013 in some areas and by 2015 in many more" (pdf).

Amit Malhotra, a vice president of Metrico Wireless, which helps test mobile device and network performance for carriers and manufacturers, says that restrictions on wireless networks' previously unlimited data plans will have a big effect on what users can do with their new iPads. "Most people are going to be limited by their data plans," he says. "One of the selling points of the iPad is the display; people are going to watch HD content, and that means larger files." Apple bumped the maximum size of mobile apps that can be installed over a wireless network from 20 megabytes to 50 megabytes last week.

A single HD movie download could be enough to exceed the limits of the entry-level data plans for the new iPad: AT&T offers three gigabytes of data every month for $30 and Verizon two gigabytes for the same price. Both companies levy fees for data used in excess of a person's plan limits.

"Verizon is offering 10 gigabytes for $80 a month, which is about six hours of Netflix, but I would imagine most people won't go for that," says Malhotra. Streaming HD content from Netflix can consume as much as 2.3 gigabytes of data an hour, the company says.

That could frustrate users, who will have to learn that life with a new iPad imposes some constraints. "What will likely happen is they will get very efficient at switching to Wi-Fi whenever there's an opportunity," says Malhotra.

Given the likely problems, Verizon, AT&T, and some app providers may find themselves under pressure to make it easier for users to track and limit their use of 4G data. Last year, Netflix added new settings for Canadian users after that country's ISPs introduced monthly data caps to many home broadband connections. Since they put an end to new unlimited data plans, both Verizon and AT&T have promoted apps that enable users to track their data usage. Buyers of the new iPad may need to become familiar with them.