Is the AT&T iPhone 4S a 4G phone or not?

If AT&T's marketing of the iPhone 4S as a 4G phone has left you scratching your head in confusion, you're not alone.

AT&T has ramped up its marketing efforts lately, airing commercials on TV that highlight the iPhone 4S as a 4G device. The TV ads emphasize that AT&T's version of the iPhone 4S can download Web content three times faster than its competitors because it's operating on AT&T's 4G network. While technically the iPhone 4S on AT&T may be faster than the same device on Verizon and Sprint, is it really a 4G device? In this edition of Ask Maggie I try to clear up the confusion.

Deceptive advertising by AT&T?

Dear Maggie,
While watching TV this morning I saw an ad for the iPhone 4S on the AT&T network. As you can see from the attached screenshot, AT&T is claiming that their 4G network makes downloads faster on the iPhone 4S. I was under the impression that the iPhone 4S is a 3G phone on all carriers. Kent German backed this up in his review of the phone.

Isn't this deceptive advertising by AT&T? The advertisement paints a picture that the iPhone 4S on AT&T is running on a 4G network.

What do you think?

Thanks,
Frank

Dear Frank,
Let me start by saying that I agree with you. I think that AT&T is confusing customers by calling the iPhone 4S a 4G phone. The device runs on AT&T's HSPA+ network, which is merely an upgrade to its traditional 3G network. That said, AT&T's claim that the iPhone 4S uses technology that is three times faster than its traditional 3G network, is true.

But it's still way slower than the 4G LTE network that the new iPad uses. It's also considerably slower than even more advanced versions of HSPA+. The iPhone 4S supports 14.4 Mbps HSPA+. Meanwhile, there are two faster versions of HSPA+ that offer theoretical network download speeds of 21 Mbps and 42 Mbps.

In other words, the iPhone 4S offers a slight speed boost over the iPhone 4 and other 3G devices. But I wouldn't say it's significant enough to put it in the same class as devices operating on a 4G LTE network or even devices operating on the newest and fastest versions of HSPA+.

But is AT&T's 4G claim for the iPhone 4S deceptive in the legal sense? Not really. The short answer to your question is that 4G is merely a marketing term. It's like calling Vitamin Water a health food. Marketers are allowed to call it whatever they want, but the truth is that Vitamin Water is full of sugar, which isn't all that healthy. And AT&T's HSPA+ version of 4G is also not what I or most other experts would consider true 4G.

I think it's unfortunate that AT&T has chosen to market the iPhone 4S in this way, since it's confusing for consumers. And it will likely only get more confusing as AT&T rolls out its 4G LTE network. This is the technology currently supported in the new iPad. And it's likely to be supported in the next version of the iPhone, which I expect will be introduced later this year.

Will the real 4G please stand up?

So what technologies are considered 4G? LTE or Long Term Evolution is what most experts consider 4G. Another technology called WiMax has also traditionally been called 4G. Sprint Nextel and Clearwire have built a 4G network using WiMax. Verizon and AT&T are building LTE networks. And Sprint and T-Mobile now have plans to build LTE networks.

The reason that LTE and WiMax have been considered 4G is that they are based on a new type of network technology that is more efficient than previous 3G technologies. LTE and WiMax use what's called orthogonal frequency-division multiple access or OFDMA modulation.

LTE and WiMax also differ from traditional cell phone technology because these networks are exclusively data-centric. While traditional cellular networks, have a separate voice network, WiMax and LTE will offer voice service over the data network, much like VoIP services like Skype or Vonage operate on a traditional broadband network. Treating voice as just another data application on the network allows for more efficient use of the wireless spectrum and network resources. And this is a big reason why carriers are switching to these "4G" network technologies.

But 4G wireless technologies are also supposed to bring much faster upload and download speeds to the network. LTE, WiMax and even HSPA+ all offer faster speeds. But the truth is that none of them live up to the official definition that has been established by the International Telecommunications Union, an international telecom standards setting body within the United Nations.

According to the ITU's IMT-Advanced specification, for a technology to be considered "4G" it must deliver downlink speeds of 1Gbps when stationary and 100Mbps when mobile. So far no commercialized standard -- whether it's WiMax, LTE or HSPA+ -- has even come close to reaching these aggressive specifications.

Today's WiMax standard has the potential to achieve theoretical downloads of 40 Mbps. And LTE can achieve speeds of 100 Mbps. There are updates to each of these standards coming. And WiMax 2 and LTE-Advanced are expected to get these technologies closer to the ITU's 4G spec. HSPA+, which doesn't use OFDMA, is also advancing and may one day achieve the ITU's 4G limits.