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Everything you need to know about 4G

By Priya Ganapati
4G technology may speed up wireless connections in some cities and on some smartphones.
4G technology may speed up wireless connections in some cities and on some smartphones.
STORY HIGHLIGHTS
  • 4G is the next step in wireless network technology
  • It promises to make mobile internet speeds "blazing fast," author says
  • The first 4G phone is called the Evo; it's made by HTC and runs on Sprint
  • 4G is available only in a handful of cities; but it could be everywhere in 2 years
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(Wired) -- If your smartphone seems more like a slowphone, hang in there. The next generation of wireless technologies, known as 4G, promises blazing-fast data transmission speeds.

The first 4G handset, Sprint's HTC Evo, hits U.S. retail stores Friday, making this a good time to answer your questions about the fast wireless technology behind the Evo.

4G is just getting started, and even Sprint's network is only available in a handful of cities. But in just about two years, 4G could be almost everywhere. All major U.S. wireless carriers are working on upgrading their systems to 4G -- though we would prefer if some, like AT&T, got their 3G networks working properly in the meantime.

So what goodness will 4G bring to the world and should you hold your breath for it? Read on for our quick guide to all those burning questions about 4G.

What is 4G?

4G is a loose term for the fourth generation of cellular communications, offering speeds that are about 10 times faster than they are on current third-generation, or 3G, networks.

Its higher data speeds could make smartphones much more comparable to PCs, giving them better multimedia and gaming capabilities.

What are the different 4G technologies?

Just as in the 3G world, 4G technologies fork into two broad camps: LTE and WiMax.

They're not aligned with the old GSM vs CDMA split, though. This time, AT&T and Verizon are moving towards LTE, while Sprint has thrown its weight behind WiMax.

There's quite a bit of debate on whether LTE and WiMax meet all the technical requirements to be classified 4G technologies. The International Telecommunications Union suggests that WiMax, the standard that Sprint calls 4G, is actually part of the 3G family, though Sprint markets WiMax as 4G and its speeds are comparable to current LTE speeds.

WiMax has its roots in the wireless broadband access industry and is supported by IEEE, while the LTE standard has been created by a consortium of mobile companies. WiMax requires a new network to be built whereas LTE is an evolution of existing CDMA/HSPA networks.

How fast will 4G be?

The maximum theoretical data transfer with 3G technology is 2 Mbps. But in practice, you won't get more than 500 Kbps to 1.5 Mbps, depending on your carrier, the location of the cell tower, congestion, etc.

4G ups the game.

WiMax can offer peak download data speeds of up to 6 Mbps and up to 1 Mbps for uploading data. WiMax rival LTE says it can do much better. It has peak download speeds of 100 Mbps and can support uploads at the rate of up to 50 Mbps.

But remember, these are theoretical speeds conjured by lab rats. Add a million devices on the network, downloading Comedy Central clips on Flash-enabled phones, video chatting, streaming the next chapter in the Saw movie franchise and uploading parodies of the latest Lady Gaga release, and those speeds will drop.

For a better idea of what you can expect with your 4G device, take a look at what tests on the Sprint WiMax and Verizon LTE 4G networks have shown. PC World reports that the HTC EVO 4G phone never broke the 3 Mbps mark in its tests of the phone nationwide. And Verizon's tests showed in the real world, its download speeds ranged from 5 Mbps to 12 Mbps and with upload speeds of 2 Mbps to 5 Mbps.

I want 4G now. Where can I get it?

About 36 U.S. cities including Seattle, Baltimore, Chicago and Dallas already have 4G coverage from Sprint. There are still some big names like San Francisco and New York missing from the list, but Sprint says 4G will arrive there by the end of the year. You can check out the detailed list of the cities that have 4G coverage on Sprint's site.

Do I need a new phone to take advantage of 4G?

Yes, you will need a new phone. The first 4G smartphone is the HTC Evo, a device running Google's Android operating system, which launches today. HTC Evo is a gorgeous device with a 4.3-inch touchscreen, two cameras, GPS navigation, HDMI output and mobile hot-spot capability. The phone costs $200 with a two-year contract. Sprint is also charging an extra $10 a month, in addition to its standard data plans, as a service fee to access the 4G network.

If you don't have 4G connectivity where you live, you can still use the phone with existing 3G networks.

Meanwhile, Samsung is creating a 4G phone for MetroPCS. The excitingly named phone SCH-r900 will have a 624-MHz processor, 128 MB of RAM, a 3.2-inch display, and Windows Mobile 6.1 operating system.

There's been an iPhone 3G, iPhone 3G S. So is an iPhone 4G next?

Sure, Apple can add the 4G tag to its next iPhone if it wants to, and "iPhone 4G" is how the company has referred to its next-generation smartphone in legal documents. But we doubt that it will have 4G network connectivity -- unless Apple's creating a phone exclusive to Sprint.

What are the 4G plans of the major U.S. carriers?

AT&T: The carrier plans to start trials of its 4G network later this year. AT&T will make the most of its LTE deployments in 2011. But even that may not be enough to free us from the tyranny of capped data consumption and gaping holes in its coverage.

Verizon: In 2009, Verizon tested its 4G wireless service in Boston and Seattle. Verizon said it plans to start offering the service commercially this year in about 30 cities so it can cover about 100 million users. By 2013, Verizon hopes to have the 4G service available nationwide.

Sprint: Sprint is leading the 4G charge with the network already available in at least 36 cities. By the end of the year, most major cities will be covered by Sprint's 4G network.

T-Mobile: T-Mobile is in no hurry to get to 4G. Maybe because it first needs to get its 3G network in order. The wireless carrier is still talking about upgrading its 3G network to 3.5 G or HSPA+. HSPA+ will come to Los Angeles and other major cities in the United States this year, says T-Mobile. 4G is clearly a long way away.

MetroPCS: The first LTE 4G phone could come from MetroPCS, which is working with Samsung on the device. MetroPCS plans to start its 4G service later this year in cities such as Las Vegas.

Give me some background: What's the history here and how did we get to 4G?

Cellular systems have evolved in four major phases or generations. The first generation, or 1G, technology was analog and transmitted voice calls only.

The second generation, or 2G, introduced digital transmissions and offered the first support for data, although the focus was still on voice calling. Second-generation phones are based on one of two standards: GSM (used by T-Mobile, AT&T, and most overseas carriers) and CDMA (used by Verizon and Sprint). In either case, average data speed on a 2G network is around 9.6 Kbps, about the same as a '90s-era modems.

The intermediate "2.5G" level is where things get a little fuzzy. In the GSM camp, a standard called GPRS, which offered better data transmission capabilities, came to be known as 2.5G. GPRS has evolved into the EDGE networks (up to 400-kbps data speeds) still used by many phones today. As for the CDMA universe, 2.5G is referred to as 1XRTT, or just 1X. In the real world, it is known as EVDO and promises download speeds ranging from 600 kbps to 1.4 Mbps.

There's been some debate on what constitutes 3G. Broadly speaking, 3G is defined not by the underlying technology, but by its speed: up to 2 Mbps. Verizon and Sprint's 3G systems are referred to as EVDO, while AT&T and T-Mobile use HSDPA. A further level, known as HSDPA+ or Turbo 3G, can support download speeds of up to 14 Mbps.

The next step is 4G.

I want all the details, the nitty-gritty behind the two 4G standards. How do they differ?

LTE or Long Term Evolution, is a standard evolved by a group called the 3rd Generation Partnership Project. It is an all-IP network based upon the same core protocol of the internet, TCP/IP.

Both LTE and WiMax use the principle of Orthogonal Frequency-Division Multiple Access, which conceptually has been around since the 1960s. OFDMA is based on the idea of frequency-division multiplexing, which is a method to transmit multiple data streams over a channel. In case of OFDMA, a digital data stream that needs to be transmitted is split into multiple pieces, each of which is modulated onto a separate carrier. These sub-carriers are combined together at the end.

The difference between LTE and WiMax lies in how they handle the channel for processing data. WiMax processes all the information in a wide channel. In case of Clearwire's implementation of WiMax, that means the about two-thirds of the channel is used for downloads, while a third is used to upload data.

LTE splits the channel into two parts using frequency-division multiplexing, so the download and upload speeds are better balanced.

Just say it. Is WiMax better or LTE?

Peanut butter or chocolate? Lost or The Wire? Havaianas or Birkenstocks? There's no easy answer. It depends on where you are and what you can get access to.

If you want 4G now, WiMax is pretty much your only choice. It's also an open standard supported by IEEE. And it is less expensive for service providers to upgrade their equipment to than LTE.

But LTE is coming and almost all the major U.S. carriers, except Sprint, will be supporting it. So ultimately, LTE might win in the long run.

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Copyright 2011 Wired.com.