What Is 4G? An FAQ On Next Generation Wireless.
1. What is 4G, and why should I care?
In theory, 4G is the fourth generation of cellular communications, a successor to current cellular networks known as 3G (third generation). In practice, 4G is a combination of marketing speak and future tech. Most of the systems billed as “4G” could be more accurately called 3.5G, or 3.75G. But the plan is for these systems to upgrade to full 4G in the future.
The promise of 4G is two-fold. Cellular data speeds will be faster — 10x faster than current 3G speeds. And the technology can help solve the “last mile” dilemma (the difficult final leg of connecting customers to a network) that prevents rural areas from getting service. 4G data can move faster, and it can get to more people.
2. So how many flavors of 4G are there, and what are the advantages of each?
Currently, advertised 4G is really just late-stage 3G. The
two formats designated by the International Telecommunication Union (ITU) as “true 4G technologies” are:
- LTE Advanced (Long Term Evolution Advanced)
- WiMAX Release 2
There aren’t any large-scale deployments of either of these. However, their predecessors — LTE and WiMAX — are currently available.
As the wireless companies advertise it, 4G consists of three different technologies:
- HSPA+ — This is more like an upgrade to regular 3G. HSPA+ offers faster speeds, but that take advantage of the same infrastructure. The first HSPA+ deployments began in 2008, and are now widely available throughout the world. T-Mobile’s “4G” network in the U.S. is HSPA+. Likewise, the first stage inAT&T’s 4G roll-out includes HSPA+.
- LTE — LTE, or Long Term Evolution, doesn’t fully comply with 4G requirements. But it is what most people consider 4G. This is the system being adopted by Verizon, Metro PCS and AT&T in the U.S. Most European carriers have also committed to LTE. It is upgradable to LTE Advanced — so once that kicks in, it will be easy to upgrade an LTE phone into full-on 4G. Verizon started deploying its LTE network in December 2010. AT&T has announced it will start rolling out 4G LTE the second half of 2011. AT&T has a HSPA+ deployment, which it will use as a backup to LTE. Both AT&T and Verizon expect to have the bulk of their LTE deployments in place by the end of 2013.
- WiMAX — This is what Sprint, Nextel and Clearwire are using in the U.S. It’s also the dominant service in Canada. Sprint’s 4G network combines the Clearwire 4G data network with Sprint’s 3G voice network.
3. When will 4G be up and running? Should I buy a 4G phone now?
Networks using either LTE or WiMAX should be able to upgrade to full 4G in the future. HSPA+ is available now. It’s a stretch to call HSPA+ 4G. WiMAX and LTE have the advantage of being precursors to the 4G standards. But the coverage area of HSPA+ far exceeds anything LTE can manage for at least three years. It’s not 4G, but it’s fast and it’s a nice stop-gap.
LTE — which is emerging as the global standard for 4G — is still in the earliest stages of deployment. Verizon is planning on doubling its coverage area in the next 18 months but it will be three years before it expects a full roll-out.
Sprint’s so-called 4G network is in 29 states and expanding all the time. T-Mobile, which has a smaller 3G network than its competitors, is trying to roll-out HSPA+ as quickly as it can. AT&T’s two-pronged 4G approach is in phase one now (HSPA+) and the LTE rollouts are planned for the second half of 2011.
Verizon announced a number of 4G devices or 4G upgradable devices at CES 2011. We should start seeing them very soon. AT&T just started shipping some of its HSPA+ devices, though a number of existing smartphones (including the iPhone 4) can work on HSPA+ networks. At Mobile World Congress, we expect to see dozens of 4G-capable handsets from manufacturers for networks all over the world.
If you want to buy a 4G phone today, Sprint is the best option in the U.S. However, the viability of Sprint’s WiMAX strategy is a concern; see below. Nevertheless, it may not matter. By the time we see widespread adoption of true 4G, your two-year contract will likely be up.
4. Is this like a VHS versus Betamax situation, where one of the flavors will die out eventually?
Sadly, yes. Fortunately, most wireless carriers seem to be rallying around one standard: LTE. It is viewed as the natural upgrade from UMTS, the 3G system in use by most of the world.
U.S. mobile users are familiar with the battle between CDMA and GSM. Verizon and Sprint use CDMA technology, while the rest of the world is on GSM. So unless a user buys a special quad-mode “world phone,” phones on those networks won’t work overseas.
But Verizon and AT&T both made the decision to adopt LTE for their respective 4G networks. LTE has already gained widespread acceptance in most parts of the world. So once LTE networks are widely deployed, manufacturers won’t have to make two different versions of the same phone (like the iPhone 4). Instead, the frequencies can just be adjusted for a particular region. The underlying technology between the phones should be the same.
In the U.S., Sprint may be the odd man out. The carrier has admitted it could make the move from WiMAX to LTE. If LTE takes off everywhere else, the carrier might have a hard time convincing phone makers to support its network.
5. How fast is 4G, really? Can I cancel my ISP subscription yet?
4G has the potential to be insanely fast. The various technologies should be able to deliver download speeds of 1Gbps when stationary (in the home), and 100 Mbps while mobile. Those kinds of speeds make cable and DSL networks look like dial-up.
In practice, neither LTE or WiMAX is going to offer that kind of speed. In the best of circumstances, users can expect around 10 Mbps from WiMAX or LTE. As coverage areas increase and networks grow more robust, that number could increase.
T-Mobile’s HSPA+ network already tops 21 Mbps in some areas. Realistically, users can expect about half of that. But T-Mobile and AT&T both plan to upgrade the HSPA+ offerings on their networks.
Most users will not be able to replace a home Internet connection with 4G, and that likely won’t change for several more years, at least. The exception is users in rural areas, where it’s often extremely difficult to get cable, fiber or DSL, and who have to rely on satellite Internet. For these users, even the first wave of LTE or WiMAX may be speedier than what they get from satellite — and at a lower price.
6. Is there such a thing as 5G, and should I wait for it?
4G was only officially ratified in December 2010, so we’re quite a few years away from 5G actually happening. The standards bodies aren’t even talking about 5G right now. But we wouldn’t be surprised if wireless carriers didn’t start describing LTE Advanced — true 4G — as 5G.
7. What is Voice over LTE (VoLTE), and why is it important?
On most 4G systems, the 4G part of the network is used for data transfer while 3G — or in some cases, even 2G — is used for voice calls.
The reason that Verizon cannot support voice and data simultaneously is because it only uses 3G for its data network and still defaults to 2G for voice. Initially Verizon was going to do something similar with LTE — that is, use LTE for data only, and default to old-school CDMA for voice calls. But earlier this month, Verizon announced it will be experimenting with Voice over LTE (VoLTE) and recently made its first VoLTE call.
Don’t expect to see phones that support VoLTE until 2012. But Verizon says some 4G phones will get software upgrades to support the feature when it is available.
Calls made from one VoLTE device to another are supposed to sound better. Because the voice network sits on top of the data network, it means video calling services like Skype can operate seamlessly (and the carriers can better compete with Skype). Increasingly, carriers are going to continue to shift from a time-based subscription model to one that is purely based on data.
VoLTE has the potential to bring both voice and data services to parts of the world that have had a hard time getting access to either.
8. Where can I learn more about 4G?
Check out these sources:
