CAMBRIDGE, Mass.--As data traffic explodes on wireless networks thanks to smartphones and other connected mobile devices, 4G wireless technology is expected to solve mobile operators' network congestion problems. But is 4G really the savior so many people expect it to be?
At the Emerging Technologies Conference at MIT here this week, experts in the wireless industry warned that it will take more than the next generation of network technology to keep up with traffic demand. Wireless operators need to think differently about how they build and manage their network as well as how they develop applications that use the infrastructure to ensure they get the most use out of their networks.
The bottom line is that building new networks is not cheap. And the latest generation of technology is not enough to meet growing demand.
"4G is a step in the evolution of wireless," said Sprint CEO Dan Hesse. "I'm sure there will be a 5G and 6G someday. I just hope I don't have to pay for it. Building networks is expensive."
Sprint Nextel is the first U.S. cell phone operator to launch a fourth-generation wireless service, using a technology called WiMax. Verizon Wireless will be the second, using a competing technology known as LTE, or Long Term Evolution. It's expected to launch its network in 25 to 30 markets by the end of 2010. And AT&T, which is suffering the most from an overburdened network, has accelerated its plans to move to 4G LTE technology.
Many wireless operators are still paying for the 3G wireless network they built only a few short years ago. And now they're opening their wallets again to build 4G networks to accommodate a flood of new data traffic. Smartphones, such as Google Android phones and the Apple iPhone, are generating 30 times more data on wireless networks than traditional feature phones. Industries, such as health care, that never before relied on wireless technology are suddenly investing in wireless infrastructure and smartphone applications, further driving demand.
While today's 3G network can accommodate much of the services available on wireless devices, these networks are already under strain. 4G is expected to help alleviate these issues by offloading the heaviest data usage.
But even though 4G promises faster download speeds and more capacity, the rapid growth in data means that wireless operators need to think differently about how they build and manage their new networks.
"4G is not a panacea," said Roger Entner, senior vice president at Nielsen. "You could very well see the same problems you've seen on 3G with 4G. It's just a matter of how long it takes to fill the 4G network."
The good news is that the move to 4G will make carrier networks more efficient than they are today. WiMax and LTE, the two technologies used to deploy 4G networks, are IP-based, which allows them to transmit traffic much more efficiently than 3G technology.
What this means is that wireless operators can either serve more customers, who in aggregate consume more data, or they can accommodate the same number of customers, who are each using greater amounts of data. Given that Sprint Nextel's new 4G handsets have bigger screens with better resolution and faster processors than other smartphones, these users are expected to consume more bandwidth than subscribers using older, less sophisticated smartphones.
"We are basically raising the water level with 4G," Entner said. "So the same ship can go more easily through that channel. But if you put a bigger ship in the channel, it will eventually hit ground, too. The ocean always has a floor."
Because upgrading networks and acquiring new spectrum is not easy or cheap, Jonathan Segel, executive director of Alcatel-Lucent's CTO Group, said during a presentation at EmTech that wireless operators also need to design and manage their networks for efficiency as well as push the application community to design more efficient applications.
"Simply creating more capacity without any control on how much data subscribers use on that network will cause the network to blow up," he said in an interview after his speech. "Usage will increase to fill the available capacity. And if the service is free or usage is unrestricted, usage goes to infinity."
Bidding adieu to flat-rate data plans
Segel said this is why flat-rate data plans, which have helped entice customers to sign up for 3G wireless data services, are unsustainable.
Some wireless providers have recognized this fact. AT&T has already moved to a tiered model. And Verizon Wireless has also said it plans to offer some type of tiered pricing plan in the near future. Even Sprint Nextel, which has far fewer subscribers than either AT&T or Verizon, and still has plenty of capacity today, has admitted that it may be forced to go to metered billing in the future.
One way to increase capacity is to reduce the size of individual cell sites.
"The biggest gains that wireless operators can get today in terms of performance comes from reducing the size of the cell sites," said Matt Grob, senior vice president of research and development at wireless chipmaker Qualcomm.
Qualcomm is working on a new version of the 4G wireless technology LTE called LTE Advanced, which allows operators to mix small and large cell sites while mitigating interference.
Because wireless broadband is a shared commodity, the more users using a service, the less bandwidth is available for each individual customer. Reducing the size of the cell sites allows operators to serve fewer customers per site while giving each user more capacity.
Segel said that many operators are already offloading traffic in densely populated areas onto "metro cells," which have a range of a few kilometers. But they're also leveraging technology that puts mini cell towers, or femtocells, in the hands of individual subscribers. Femtocells are portable cell phone towers used in homes and offices that offer enhanced cell phone signals within a 10-meter radius around the device.
Femtocells help fill in coverage gaps that often occur in homes where traditional cell phone signals are weak. The three largest wireless operators in the U.S., Verizon Wireless, AT&T, and Sprint Nextel, each offer femtocells to help them extend coverage and capacity for their existing 3G wireless networks. They generally cost between $150 and $250 and they offload the wireless traffic onto wired broadband connection.
But making cell sites smaller can cause interference issues.
"You can only split the cell sites so far," Entner said. "There are physical limits."
Segel admitted other techniques are necessary to stretch the life of a given network. Specifically, he said that operators need to add intelligence into the network so that the delivery of different types of traffic is optimized.
For example, he said that voice traffic is very sensitive to latency. So networks need to have policies in place to make sure that voice and audio traffic is handled without delay through the network. Meanwhile, video eats up a lot bandwidth, but it's not as sensitive to latency since it can be buffered. But it is more sensitive to jitter.
"Recognizing how traffic should be treated differently throughout the network is very important," he said. "Without that, the best you can hope for is for the least common denominator in terms of quality."
In addition to managing the network intelligently, Segel said more efficient applications need to be developed. He used video as an example. Video eats up huge amounts of bandwidth on the network, but Segel said new ways of delivering the content can be delivered to minimize bandwidth consumption. For example, the video content could be pushed closer to the subscriber.
"These new 4G networks will not be overloaded anytime soon," he said. "But we know that the more capacity that is available to mobile users, the more they will consume, so increasing bandwidth or spectrum alone is not enough."