Is ’5G’ mobile broadband just around the corner? IMT-Advanced explained
Can't wait to get on the 4G LTE bandwagon? Think bigger. A new standard called IMT-Advanced promises speeds up to 10 times faster, and it's just been approved.
With Verizon, AT&T, and Sprint racing to bring 4G LTE services to customers (and T-Mobile having long marketed its hot-rodded HSPA+ as 4G technology) it might seem the 4G mobile broadband is on the verge of going mainstream. But what if we said these technologies were really just a sort of “4G Lite,” and the real 4G was just around the corner — and up to 10 times faster than what mobile operators are touting as 4G today. Would you be interested?
That’s exactly what’s happening. At its meeting this week in Geneva, Switzerland, the International Telecommunications Union, the United Nations agency focused on communications technology, has just approved the specifications for IMT-Advanced.
“IMT-Advanced marks a huge leap forward in state-of-the-art technologies, which will make the present day smart phone feel like an old dial-up Internet connection,”" said ITU secretary-general Hamadoun Touré, in a statement. “Access to the Internet, streaming videos, and data transfers anytime, anywhere will be better than most desktop connections today.”
Sound good? We thought so.
What is IMT-Advanced?
IMT stands for “International Mobile Telecommunications. For the last 25 years or so, the ITU’s IMT standards have helped shape the way mobile services have developed worldwide. IMT-Advanced isn’t a specific technology like HSPA+, WiMax, or LTE—rather, it’s a specification and list of requirements for high-speed mobile broadband service. Communications developers still have to build gear that meets the specs, and they can do that any way they like. Once their technologies have been proven to meet the requirements, they can get the official IMT-Advanced designation.
The last set of standards the ITU approved were called IMT-2000, and they’re the basis for the 3G technologies carriers have been rolling out for the last decade. IMT-Advanced is the next generation of these technologies, so technically IMT-Advanced defines 4G. And guess what? The LTE, WiMax, and HSPA+ services that have been rolled out to consumers and marketed as “4G” don’t measure up.
Right now two technologies have been found to meet the IMT-Advanced criteria: WirelessMAN-Advanced and and LTE-Advanced. WirelessMAN-Advanced is an evolution of the 802.16e technologies that serve as the basis for today’s WiMax services (WiMax is essentially a friendlier marketing term). As the name implies, LTE-Advanced is a further refinement of existing LTE technology that brings it into full compliance with IMT-Advanced requirements.
Just as with WiMax and LTE today, there will be likely be competing technologies bringing IMT-Advanced capabilities to consumers. Right now, LTE-Advanced would seem to have the upper hand, primarily because the vast majority of wireless operators around the world have worked to standardize on current LTE technologies, and that ought to give them a leg up on moving to LTE-Advanced. However, there are networks — like Sprint and Clearwire along with others in South Korea, Russia, Belarus, and Nicaragua — that have chosen to run with WiMax technology.
What will IMT-Advanced bring?
The main benefit of IMT-Advanced will be bandwidth, but we’ll simplify that to speed.
Today, most mobile data users rely on 3G technologies, and typical download rates are around 2 Mbit/s downstream, and far less upstream — something like 200 Kbit/s. Given the right conditions, 3G technology can hit 14.4 Mbit/s downstream and 5.76 Mbit/s upstream. Tweaks to the systems and HPSA+ services like those operated by T-Mobile can push that theoretical limit to 42 Mbit/s downstream — and T-Mobile hopes to be able to crank that up again to 82 Mbit/s downstream in order to compete with LTE services.
The “4G” WiMax and LTE technologies being marketed today improve on 3G capabilities. In ideal conditions (and with a full 20MHz of frequency space available) WiMax can offer up to 128 Mbit/s downstream and 56 Mbit/s upstream, and LTE has a theoretical peak capacity of 100 Mbit/s upstream and 50 Mbit/s downstream in the same conditions. Of course, real-world bandwidth is going to be lower: Some of the capacity is taken up with protocol transaction and housekeeping to keep things moving along, and sometimes problems or interference means data has to be re-sent. Furthermore, not all base site locations are going to have a full 20MHz available, and a site’s bandwidth is shared amongst all users connected to a particular site. Those ideal conditions mean you can’t be moving: The more (and faster) your mobile device moves, the worse its data performance becomes.
Mobile technologies implementing the IMT-Advanced requirements will blow all those technologies out of the water. IMT-Advanced is to offer a nominal data rate of 100 Mbit/s downstream while moving, even at high speeds relative to a base site. That means users in cars, trains, and even planes should be able to receive mobile broadband service in the neighborhood of theoretical maximums for current “4G” mobile broadband technology. And it gets better: if you’re not moving, IMT-Advanced technologies should be able to deliver a theoretical maximum of 1 Gbit/s, which is ten times more bandwidth.
If all that seems like technical gobbledegook, think of it this way: With IMT-Advanced technology, it should take about 20 seconds to download a full-length (44 min) standard-definition television episode to a smartphone. Want high-definition? It’ll take less than a 90 seconds. How about a whole album of music? Roughly one minute at full CD quality, no compression. That’s faster than most users’ fixed-line broadband connections to their homes.
IMT-Advanced also includes new techniques for dynamically sharing network resources, so base stations using the technology can support more concurrent users per cell. The technology is also designed to offer global roaming capabilities and seamless handoffs between base stations, meaning users are less likely to experience hiccups as they move between one site and another. For markets like the United States where available radio spectrum has often been sliced up into lots of tiny pieces, IMT-Advanced also scales well from small to large blocks of spectrum, enabling operators to use their spectrum more efficiently — although the best performance (of course) comes with the biggest blocks.
How will all that bandwidth be used?
Like current WiMax and LTE technologies, IMT-Advanced 4G connectivity can be used for a broadband connection to homes or businesses. Since those connections won’t be moving, fixed-point connections should enjoy lots of bandwidth, assuming providers want to offer affordable service plans. For folks who can’t get cable, fiber, or high-speed DSL connections (or just don’t like the strings providers attach to those services) IMT-Advanced technologies might be a viable alternative, particularly in rural areas and other communities under-served by existing broadband providers.
For mobile users, IMT-Advanced holds out the possibility of significantly raising or perhaps eliminating those pesky data caps imposed by mobile operators. As LTE users are already discovering, data caps can be a significant impediment to use: Some users of Verizon LTE have reported they could potentially blow through a month’s worth of LTE data service in less than an hour of Internet use.
The notion that raising the bandwidth capabilities for mobile networks could raise or eliminate data caps might seem counter-intuitive: After all, U.S. mobile operators (particularly AT&T) have long been complaining that they have trouble keeping up with the data demands of their customers.
However, the only way mobile operators will be able to sell services using the bandwidth offered by IMT-Advanced technologies will be to introduce innovative new services that require that bandwidth. Obvious applications include things like offering high-definition streaming video. With IMT-Advanced technologies, mobile users might be able to engage in high-definition video chats or watch live, high-definition television (or, heck, even slap on 3G headgear) while on high-speed commuter rail — and never experience a hiccup.
When will IMT-Advanced reach the streets?
The ITU’s formal adoption of the IMT-Advanced specification doesn’t do much for getting the technology deployed. The ITU doesn’t develop or build telecommunications gear itself. Furthermore, despite its role within the United Nations and broad international support, ITU requirements aren’t considered binding standards. The ITU is just one standards body among many: the WiMax Forum, 3rd Generation Partnership Project (3GPP) and Institute of Electrical and Electronics Engineers also play roles in solidifying telecommunications technologies. In other words, implementation details still need to be hashed out amongst other standards bodies, licensing issues resolved, and then telecommunications developers can start working to build gear and adapt their existing technologies to support IMT-Advanced. Bottom line, it’s going to be at least a couple years before IMT-Advanced starts to trickle into the marketplace.
For now, when AT&T, Verizon, Sprint, and T-Mobile are trying to peddle their latest 4G services, just remember “real” 4G is just around the corner — although, when it gets here, we’re sure mobile operators will be tempted to call it “5G.”