iPhone 4 compatible with 4G ?

There is no such thing as "4G". No carrier supports anything that is technically called "4G". There is one carrier that has deployed WiMax, which is not going to become a worldwide standard, and their marketing department calls it 4G. But it isn't.

However, the iPhone 4 supports HSUPA, which has a maximum speed of 7.2 Mbps. Currently AT&T only supports it to 4 Mbps. The iPhone 4 has been tested at up to 4 Mbps on AT&T. If there were a carrier that supported 7.2 Mbps I'm sure the iPhone 4 would work on it.

Even if the next generation iPhone is an LTE (4G) network compatible phone, it will probably take AT&T 2-3 years to roll out their LTE network extensively besides major markets only. Unless you are in an area where AT&T has rolled out their LTE network, it won't make any difference. You will still be connected to AT&T's 3G or EDGE network - whichever is available at the time as you are now. Just like those with a 3G network compatible phone when in an area where AT&T's 3G network isn't available.

There won't be 4G in 2012 either. Forget the names. The iPhone 4 in a 3g area is faster than anything that will be available in the next 3 years. And it's as fast or faster than Sprint's "4g", which isn't really available except in some smaller markets.

The next major upgrade will be LTE, and that won't be widely available for 3 or 4 years. And there's no guarantee it will be any faster than HSUPA that you can get with your iPhone 4 today.

The "4" in the name iPhone 4 means fourth generation of the iPhone, not 4G. HSPA+ (3.5G) which the iPhone 4 can run on currently supports speeds up to 42 Mbps depending on the carrier. I'm using an iPhone 4 here on Rogers HSPA+ network which currently supports up to 21 Mbps which the carrier is upgrading to support 42 Mbps to launch when there's hardware capable of using it. Due to the iPhone 4 only has a maximum download speed of 7.2 Mbps due to the HSPA (3G) chip used this is the maximum speed one can get even if you're running on a faster network whether it's 3.5G or 4G. My HSPA+ USB modem (Rogers Rocket Stick MF668) which I use with my MacBook Pro supports up to 21 Mbps. It is unfortunate that Apple opted for a HSPA (3G) chip instead of a HSPA+ (3.5G) chip but this could be due to either cost or that the carriers in the USA are taking longer to get the speeds other countries such as Canada are using. It's difficult to sell a 3.5G iPhone in the USA when the carriers such as AT&T currently aren't able to provide that speed.

Why isn't WiMax 4G?

AT&T needs to get its network up to 3G everywhere first and to have that 3G working everywhere before I would even think about 4G. I have been fighting with AT&T to get my speeds over 600K download and 70K upload and I am supposed to be in a good 3G area.

AT&T will never have their 3G network everywhere just as Verizon's so called 3G network isn't everywhere, and the same for T-Mobile's 3G network.

I doubt AT&T will be following your advice.

deggie wrote:
Why isn't WiMax 4G?

Well, I guess you have a point. As there is no definition of 4G Sprint can call theirs 4G, or can call it chopped liver. That doesn't make it either. But consider:

EDGE (2G) is about 10 times as fast as GPRS.

AT&T's 3G is about 10 times as fast as EDGE.

Verizon's EVDO (they didn't call it 3G until recently) is about 6 times as fast as EDGE.

Sprint's "4G" is twice as fast as AT&T's HSDPA 3G, and slower than AT&T's HSUPA 3G, which even AT&T doesn't call 4G.

Of course, what all of this ignores is the fact that raw speed is close to meaningless, just like megapixels has practically nothing to do with picture quality. Everyone is advertising the one parameter that makes them look best. What you should really care about is how fast a page loads or how good a picture a camera takes, not the details of the technology that produces he result.

For a camera the REALLY important values are lens quality and sensor size. A good lens with a 1 megapixel camera will take better pictures than an iPhone with 5 megapixels.

For data access the REALLY important value is latency - how long you have to wait before that lightning-fast data transfer starts. Which is over a second over most cellular networks. The next most important is processor speed; After the data arrive how long will it take to render? Raw speed is way down on the list of factors that affect real-world performance.

And for data transfer speeds 1 Mbps is more than fast enough; very few web sites can keep up with even half that. You will see no significant difference between 3G, WiMax, 4G, or whatever G in doing real world tasks. For comparison note that the much vaunted "T1" dedicated circuit is only 1.55 Mbps. What it has that makes it so valuable is very low latency; typically under 10 ms.

"As there is no definition of 4G..."
Of course there is.

And that definition is?

Don't bother; here's Wikipedia's definition: http://en.wikipedia.org/wiki/4G

+4G refers to the fourth generation of cellular wireless standards. It is a successor to 3G and 2G families of standards. The nomenclature of the generations generally refers to a change in the fundamental nature of the service, non-backwards compatible transmission technology and new frequency bands. The first was the move from 1981 analog (1G) to digital (2G) transmission in 1992. This was followed, in 2002, by 3G multi-media support, spread spectrum transmission and at least 200 kbit/s, soon expected to be followed by 4G, which refers to all-IP packet-switched networks, mobile ultra-broadband (gigabit speed) access and multi-carrier transmission. Pre-4G technologies such as mobile WiMAX and first-release 3G Long term evolution (LTE) have been available on the market since 2006[1] and 2009[2][3][4] respectively.+

Note that this definition (there are others, which is why I said there is no clear definition) requires GIGABIT speeds, which even LTE cannot achieve. And it specifically excludes WiMAX.

If you dig a little deeper into Wikipedia entries (not my favorite reference by far) they discuss WiMax further and do concede that it is indeed 4G, not that there is an "official" definition of 4G anywhere nor any standards laid out that it has to meet. But it is a successor to their EVDO 3G, hence 4G, and it does have many improvements over what has become known as 3G. It has a serious downside in that it requires many, many more cell sites than LTE to cover the same area.

@ the OP

Just because it is telling you that you will not be able to upgrade until 2012, that doesn't mean it's set in stone. As someone already explained to you in another thread, AT&T is usually pretty good with allowing someone to upgrade to a next generation iPhone even if your contract currently says otherwise.

Prime examples are my husband and myself. My iPhone was only 1 year into the contract when the iPhone 4 came out, and I had no problem snagging one at 199.-
My husband had just received an iPhone for Christmas last year, and guess what?
By the time the iPhone 4 launched, he was eligible for the iPhone 4 at the same discounted rate.

AT&T WANTS you to stick around and not end your contract when it's up, so upgrades on smartphones of this magnitute are usually available as soon as the new 'superphone' goes on sale. This way, you're locked into yet another contract for a maximum of two years, or sooner if you decide to pay off what is left of your contract.

So I wouldn't worry too much. Just wait until June of next year, and enjoy your iPhone 5 at that time.

And thus you have just proved my point, that there is no consistent or generally agreed definition of "4G". So anyone can call their service 4G, or not, or 3.5G, or 6G. The "definition" is meaningless.

But if you woke a cellular engineer at 3 AM and asked what 4G meant she would probably say "LTE" 😉

I'll bite Lawrence.. what does it stand for?..lol