“What is 4G? The ultimate guide to 4G wireless networks, phones, coverage, and more”

What is 4G? The ultimate guide to 4G wireless networks, phones, coverage, and more

Posted: 23 Feb 2011 12:52 PM PST

If you've seen or heard an ad about a cell phone or wireless plan lately, you may have noticed that a lot of new buzzwords are being thrown around. Words like 4G, LTE, and WiMax seem to have replaced the last set of words we barely understood: 3G, GSM, and CDMA, but what does it all mean? Is it all a bunch of marketing nonsense or are these words you should know and understand? We've got the scoop in our official mobile broadband FAQ.

The basics of 4G

What is 4G?
Do I have a 4G-capable phone?
Does my wireless carrier offer 4G?
What is the ITU?

The three flavors of 4G

What is WiMax?
What is LTE?
What's the difference between LTE and WiMax?
What is HSPA+?

4G wireless carrier breakdown

How is AT&T handling 4G?
How is Sprint handling 4G?
How is T-Mobile handling 4G?
How is Verizon handling 4G?

The basics of 4G

What is 4G?

Don't let this surprisingly intuitive naming scheme spin you around: 4G simply means "fourth generation." It's the next step up in mobile Internet speed from 3G, which is a term you started hearing a few years back. 3G is what you use if you browse the Web on your smartphone right now. It uses the networks built by wireless carriers and transfers data over them at speeds up to 2 megabits per second (Mbps), making it possible to load a website and stream videos… just not very fast. 4G networks will change that, offering download speeds comparable, if not faster than, the Wi-Fi and the broadband Internet you get on your laptop at home – all over the airwaves.

4G networks will eventually reach speeds of up to 100 Mbps, but at launch they'll likely offer actual speeds around 1Mbps to 12Mbps, which puts them about on par with Wi-Fi 802.11b networks. For example, my current cable Internet download speed at 5 p.m. in Chicago, IL is about 6Mbps. Your Internet speed is probably no greater than 15Mbps on a good day. Want to know your connection speed? Test it.

Do I have a 4G-capable phone?

Probably not, unless you just bought it recently and the phone had "4G" in its name or plastered all over its box. Wireless carriers and cell phone manufacturers are using the word 4G like it's the holy grail, so if your phone doesn't blatantly say it's 4G, it probably isn't. Most 4G phones are and will be smartphones, so if you have an older flip phone, you're out of luck for now.

Does my wireless carrier offer 4G?

All four major carriers – AT&T, Verizon, Sprint, T-Mobile – are offering services they call "4G," but their actual speeds and availability vary wildly. For the most part, 4G access on most carriers is limited to a handful of major cities around the United States, but coverage is expanding fast. To attain 4G speeds, carriers are spending billions of dollars to upgrade (or replace) their wireless networks. In our 4G carrier breakdown below, we'll go into specifics on each carrier's current 4G status and compatible handsets.

What is the ITU?

The ITU, or International Telecommunications Union, is an agency of the United Nations that sets telecommunication standards for the world. The ITU coined the terms 3G and 4G and establishes which technologies meet the requirements to qualify for the labels. Initially, the ITU claimed that HSPA+ technology didnâ€™t qualify as 4G, but reversed its decision in December 2010.

The three flavors of 4G

What is WiMax?

WiMax stands for "Worldwide Interoperability for Microwave Access." It is an ITU-approved, fourth-generation mobile broadband technology that attempts to mimic the abilities of Wi-Fi wireless Internet, but over a mobile phone network using an open protocol (802.16m). Think of it as a patchwork of Wi-Fi hotspots that, instead of reaching for a few hundred feet, can stretch for miles and overlap, eliminating coverage gaps. It provides fixed and mobile Internet access for compatible devices with less interference than traditional Wi-Fi. Theoretically, a WiMax tower could provide broadband wireless Internet over a 30-mile range, though most stations currently achieve much less. Current WiMax users can realistically expect about 3Mbps to 6 Mbps download speeds.

If you've heard of WiMax, it's probably due to Sprint, which is working with Clearwire to develop an extensive WiMax network. It is currently available in select cities. More on this in our Sprint section later on.

What is LTE?

LTE stands for "Long Term Evolution," and is an ITU-approved 4G mobile broadband technology. It is a direct competitor to WiMax. LTE is more of a successor to current mobile 3G standards than WiMax. However, instead of transmitting data using microwaves, LTE uses radio waves. Theoretically it can attain speeds up to 100Mbps, though real-world speeds on Verizon's network are around 6Mbps to 12 Mbps. LTE was developed as a long-term alternative to DSL, cable, and other wired forms of Internet.

The two largest carriers in the United States, AT&T and Verizon, are both investing in LTE networks, though Verizon has already launched its network. MetroPCS is also working on a LTE network.

Wait, so what's the big difference between LTE and WiMax?

WiMax is based on IEEE (Institute of Electrical and Electronics Engineers) standards, meaning it uses an open protocol that has been debated and approved by a large community of engineers. LTE, on the other hand, is a standard that was cooked up by the 3GPP (Third Generation Partnership Project), which is an organization consisting of wireless agencies and telecommunications companies. The 3GPP organization came up with 3G standard for GSM some years back, which was adopted by a majority of wireless carriers around the world (except here in the U.S. where Verizon and Sprint chose to use CDMA).

However, LTE and WiMax aren't enemies like CDMA and GSM have been. Both technologies use OFDM (Orthogonal frequency-division multiplexing), which means that unlike competing 3G networks like CDMA and GSM, WiMax and LTE are more like siblings. They aren't entirely incompatible. Hopefully, it will be easier and cheaper to design devices that incorporate both technologies.

Similarities: Both use SIM cards, both are backward compatible with existing CDMA and GSM networks, both use OFDM and MIMO (Multiple In, Multiple Out), both have similar speeds, and both are IP-based.

Okay, then what the hell is HSPA+?

Calm down. We were getting to that. HSPA+ stands for "Evolved High-Speed Packet Access." It has been touted by some carriers as a 4G mobile broadband network type, and the ITU recently changed its 4G definition to put HPSA+ under the umbrella, but really, it is merely an upgrade to existing 3G GSM technologies. Think of it as a stopgap or bridge between 3G and 4G. Though it offers download speeds that can theoretically reach 84 Mbps (possibly even higher in the future), it is not a next-generation network. It still uses the old interface and standards implemented years ago for 3G, and lacks the response time of LTE and WiMax. It's like comparing a Formula 1 race car to a souped-up Toyota Camry; the Camry may move fast, but it wasn't designed to race. HSPA+ is the definition of an old dog that has learned new tricks. LTE has a lot of small back-end improvements to its core technology that better suit it for the future, but many carriers may stick with HSPA+ for a couple years due to the savings. HSPA+ networks will likely feature download speeds from 1Mbps to 7 Mbps at first, though performance may vary wildly.

T-Mobile has been a big proponent of HSPA+, touting itself as "America's largest 4G network." More on that below. Since it is relatively cheap and speedy to upgrade a GSM network to HSPA+, both T-Mobile and AT&T have implemented HSPA+ in a large number of major markets and are quickly rolling the service out across the country. AT&T is also developing a next-generation LTE network.

4G carrier breakdown

In this section, we will detail each carrier's current and future 4G plans, including what network technologies they've chosen, what 4G devices are available, in what geographical regions 4G coverage is accessible, how fast they're network is, and how much they're charging.

AT&T's 4G network

Summary: If you're on AT&T, you won't get left behind, but the carrier was caught off-guard by 4G. In fact, AT&T actually got mad at Verizon and T-Mobile for discussing 4G services back in May 2010. Since then, the carrier has completely gone against its own criticisms and marketed its own 4G services and devices using HSPA+, with a promise that LTE is coming by mid-2011. AT&T claims its strong implementation of HSPA+ will allow it to have a strong backup if customers move out of LTE range.

Technology: AT&T is currently using a standard called HSPA+ 21, which allows for theoretical maximum download speeds of up to 21Mbps, though actual rates are said to be around 1Mbps to 7Mbps. We do not yet know the details on AT&T's planned LTE roll-out later this year.

Devices: Motorola Atrix 4G, HTC Inspire 4G, Samsung Infuse 4G (coming soon), and AT&T USBConnect Shockwave 4G modems. (All current device offerings are only HSPA+ compatible.)

Coverage: AT&T's coverage map is right here. Currently, only a few major cities have actual HSPA+ access.

Sprint's 4G network

Summary: Sprint went all in with WiMax, but now it seems to be having some buyer's remorse. In February 2011, a Sprint executive claimed that the company is not shutting the door on LTE, especially since its current network could be upgraded to the new service. WiMax, on the other hand, has required Sprint to work with Clearwire, which has purchased a chunk of 2.5GHz spectrum needed to run the network.

Technology: Sprint 4G runs on WiMax in collaboration with Clearwire. It claims that users will get average download speeds around 3Mbps to 6Mbps and peak download speeds of more than 10Mbps. Check out of hands-on test of Clear's WiMax service (the same network Sprint uses) in Portland.

Devices: HTC EVO Shift 4G, HTC EVO 4G, Samsung Epic 4G, Dell Inspiron Mini 10 (netbook), Dell Inspiron 11z (netbook), Sprint 3G/4G USB U600 (modem), Overdrive 3G/4G Mobile Hotspot (modem), Sprint 4G USB U1901 (modem)

Coverage: Sprint's coverage selector is right here. The service is still available in 76 major cities and the carrier claims there are 120 million people living in areas where its 4G is available.

T-Mobile's 4G network?

Summary: T-Mobile has been aggressively rolling out HSPA+ upgrades to its networks. The carrier claims to have the "largest 4G network," which may be true in overall geographical area covered, though we suspect AT&T will soon catch up with its HSPA+ enhanced network. T-Mobile executives claim that they plan to hold off on LTE upgrades until 2013.

Technology: T-Mobile 4G runs on a version of HSPA+ with theoretical download speeds up to 21Mbps. Realistically, most users will probably get somewhere around 1Mbps to 7Mbps. Check out our hands-on test of T-Mobile's HSPA+ service in Portland.

Devices: T-Mobile G2, T-Mobile myTouch 4G, Dell Streak 7 (tablet), Dell Inspiron Mini 10 4G (netbook), T-Mobile Rocket 2.0 4G Laptop Stick (modem)

Coverage: T-Mobile's 4G coverage map is right here. The carrier claims more than 200 million people live in areas where T-Mobile 4G is already available; it is available in more than 80 cities.

Verizon Wireless's 4G network?

Summary: Verizon's 4G strategy may be the most advanced and forward-thinking of the bunch. The carrier has already launched its LTE network in the States and announced more than 10 devices that will support 4G LTE connections in the first half of the year. Unfortunately, none of them have been released yet. The first will be the HTC ThunderBolt, which hits shelves Feb. 24. Verizon also plans to upgrade the quality of its voice calls and video chat in the coming months.

Technology: Verizon believes its LTE network will retain speeds of 5Mbps to 12Mbps, even in congested areas and periods of high usage. Testers in the beta program late last year were actually attaining much faster speeds, leading some to believe Verizon's estimates are conservative. No matter which way you slice it, Verizon's minimum LTE speeds appear likely outrace a majority of other 4G offerings.

Devices: HTC ThunderBolt (available Feb. 24), LG VL600 (modem), Motorola Droid Bionic (coming soon), Samsung 4G LTE (coming soon), LG Revolution (coming soon)

Coverage: Verizon's coverage map is right here. Currently, the service is available in 38 markets, 60 major airports and is expanding quickly. Verizon expects to cover areas with a combined population of more than 110 million by the end of 2011 and have complete 4G coverage by the end of 2013.

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