You're lost in a city of 6 million people. It's midnight, you're in a scary neighborhood and you desperately need directions to your hotel. No problem. Just whip out your smartphone, which will bail you out of this sticky situation by providing detailed, interactive maps.
There's just one problem -- your phone's data connection is achingly, exasperatingly slow. So slow, in fact, that you finally give up on your much-cursed phone. And then you buy a map at a gas station.
Without a speedy data connection, your smartphone seems, well, pretty dumb. No matter how expensive or fancy your phone, you still depend on a wireless network to deliver the goods – the data, that lifeblood of all things digital. And the current generation of 3G (third-generation) networks, while speedy, often can't provide a dependable mobile Internet experience.
What your suffering smartphone really needs is the kind of broadband (high-speed) Internet service that you tap into on your home computer. You need mobile broadband. You need 4G. And so does everyone else.
In 2009, for the first time, network traffic for mobile broadband exceeded traffic for voice calls [source: Ericsson]. And demand for data will be 33 times higher by 2020 [source: 3GPP]. As more and more people buy mobile devices that require lots of data, networks have to keep up.
To do that, service providers (called carriers or operators depending on your location) are investing heavily in their infrastructures, meaning the hardware and software that makes cell communications possible. By some estimates, they'll spend as much as $53 billion in the United States alone, in large part to support the expansion of faster networks, often referred to as 4G (fourth-generation) [source: Fool.com].
But what exactly are 4G networks? And why are they the subject of so many loud, brash commercials? What makes them different from old-school 2G networks, which primarily worked for voice calls? And how can you tell a 4G network apart from 3G?
The answers aren't always as clear cut as we'd like them to be. In a sense, the world of 4G is as disorienting as being lost in a megalopolis without your collection of online maps.
But have no fear. We'll steer you through the acronyms and the marketing convolutions and guide you past the skyscrapers of techno mumbo-jumbo. Along the way, we'll show you how lickety-split 4G speed could power the mobile Internet into a new age.
Wireless networks are hodgepodge of various and overlapping technologies. No matter how convoluted the acronyms, what it always boils down to is this -- wireless networks are radio systems. You can read about the basics of cell phone technology in How Cell Phones Work and How Smartphones Work.
No matter which wireless technology might dominate your part of the world, you have something in common with the rest of the planet – you're part of the wireless explosion. There are nearly 6 billion cellphone subscriptions active in the world [Source: 4G Americas], and mobile phones are only getting more and more popular.
To keep up with the demands of billions of wireless phone customers, networks must change and adapt to handle more users and more data. Every leap in network performance or capability is denoted (often vaguely) as a so-called new generation.
Old-school 1G (first-generation) networks, built in the 1980s, were analog, and they carried only voice calls. In the early 1990s, digital 2G (second-generation) began their ascent, allowing for basic data services such as text messaging and email.
3G networks began spreading in the early 2000s, and with them, so too did the concept of mobile Internet. With a fast connection, you could surf the Web, play streaming audio, although the experience was sometimes obscenity-spewing slow.
Then consumers began clamoring for even more fabulous, Web-centric mobile capabilities. Mobile devices with advanced and data-hungry capabilities exploded in numbers. In the meantime, network infrastructures began creaking under the weight of immense demands for data.
3G needed more oomph. It was time for wireless networks to evolve once again, this time to provide speedier mobile broadband service. That time is now.
These days, network generational lines are a little more confusing. There's no universally recognized standard for 4G.
So, faster-than-3G systems are often referred to as 3.5G or 3.9G, or simply 3G+. However, marketing campaigns from major carriers, who are always looking for a competitive edge, refer to these networks as 4G. In short, 4G is merely a marketing term. It means only that a network is faster than 3G. That's it.
But there are different flavors of 4G, or mobile broadband. On the next page you'll see how 4G is different from its wireless forebears, and then delve into the details of what makes it so much faster than the first 3G systems.
Using these standardized packets, your data can traverse all sorts of networks without being scrambled or corrupted. To send and receive packets, first your phone has to communicate with a base station. A base station is just industry speak for those tall cell towers affixed with all sorts of antenna equipment; a base station relays data to and from the Internet and your mobile device.
There are a lot of different methods (called air interfaces) to establish a link between the base station and phone. You can read more about older air interfaces and their tangle of acronyms here in How Cell Phones work. We'll touch on newer 4G air interfaces later.
We won't blind you here with the definitions for each acronym, but common 3G interfaces include CDMA2000, HSPA, 3G LTE, EV-DO Revision B, DO Advanced, and Mobile WiMAX, to mention just a few. Each of these interfaces transfers data in different ways through radio waves in a given spectrum. You can quickly review those older technologies here.
Currently, 4G systems aren't really all-IP, simply because there's still lot of overlap between 3G and even 2G networks throughout various countries and around the world. But as 4G infrastructure advances, the all-IP data delivery system will be more fully realized.
This idea of IP-based wireless is just one factor that defines 4G. On the next page you'll see that a lot more ingredients go into the recipe that makes for tasty 4G performance.
Mark Murphy, innovation lead at Ericsson, says that beyond speed, 4G has some other defining traits that make it stand apart from older technologies.
4G has higher capacity, meaning it can support a greater number of users at any given time. It sports higher data rates, so that multimedia applications such as video calling or YouTube clips work more smoothly. With a 3G tower, about 60 to 100 people can share the signal and get fast, reliable service. A 4G LTE (Long Term Evolution) tower, however, can serve around 300 or 400 people.
And 4G features reduced latency. With less latency, or delay, you see more immediate response to your commands, which is especially helpful when you're playing fast-paced online games or remotely controlling a car or robot. A network that qualifies as real-time speed has a latency of 50ms (milliseconds) or less; 4G LTE has a latency of only around 20 to 40ms. Low latency also means voice calls don't have any lag or echo, echo, echo.
4G is more spectrally efficient than 3G. Think of radio spectrum as a pipe of a certain diameter; only so much data can go through that pipe at one time. But 4G uses clever coding schemes to dramatically increase the amount of data that rushes through the spectrum. Ultimately, it delivers more bits per hertz than 3G.
But what it is about 4G that actually drives these improvements? Keep reading and you'll see how 4G gets its real horsepower.
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