iPhone

iPhone 4 upgrades to HSDPA/HSUPA can double 3G bandwidth speeds

The iPhone 4 is catching a lot of criticism for the left-side antenna issue, but we have speed tests that reveal the iPhone 4 can effectively double 3G bandwidth speeds on AT&T.

The iPhone 4 is catching a lot of criticism for an antenna issue that is causing some users to lose connectivity when holding the iPhone 4 in a way that blocks the lower left corner of the device. Apple's reaction to the problem has been typical and disappointing: "Just avoid holding it in that way."

I have not been able to replicate the antenna problems that have been reported. In fact, in my first two days of using the iPhone 4 I've had a shocking discovery: It is giving me far better bandwidth on the AT&T 3G network.

I started noticing this on Thursday after I picked up the iPhone 4. The first bandwidth speed tests that I ran showed that I was getting much higher bandwidth numbers that I was used to seeing on AT&T. I was getting over 2 Mbps on downloads and over 700K on uploads. At first, I didn't think too much of it, because it was only a little higher than normal. In my 3G bandwidth tests on various devices in different cities across the U.S., the 3G speeds tend to top out at about 1.0-1.5 Mbps down and 250-500 Kbps up.

However, the increase was enough to pique my interest and so I ran a bunch of additional speed tests today between home and work and a couple other locations. The results were startling. In several spots I was able to get upwards of 4.0 Mbps down and 1.0 Mbps up.

I immediately wondered if AT&T had done a network upgrade to coincide with the iPhone 4 launch. Unlike San Francisco and New York City, AT&T has a solid network in the area where I live -- Louisville, Kentucky (where TechRepublic launched as a startup in 1999 and the editorial department still has its headquarters today). This area was a part of the traditional stronghold left over from Cingular and Bell South.

So, in order to verify whether this was just a general AT&T upgrade or if there was something going on with the iPhone 4, I had one of my colleagues who has an iPhone 3G come into my office so that we could both run the same speed tests and compare the results.

We used the two most common iPhone speed test apps, the one from Speedtest.net and the one from Xtreme Labs. I had him start his test and then I started mine. In both cases, the iPhone 4 blew away the iPhone 3G. Take a look at the results.

Speedtest.net

Xtreme Labs

More iPhone 4 speed tests

To give you a look at the rest of the speed tests that I ran on the iPhone 4 in various locations today, here's a screenshot of the history from the Xtreme Labs app.

HSDPA and HSUPA

The primary source of the iPhone 4's speed boost is the upgrade to HSDPA (which began with the iPhone 3GS) and HSUPA (which is new to the iPhone 4). AppleInsider explains:

"Support for both HSDPA and HSUPA in iPhone 4 makes the phone a '3.5G' device and means it can theoretically achieve 7.2 Mbps downloads and 5.8 Mbps uploads, but those capabilities are also dependent upon the mobile operator. In the US, AT&T's 3G HSDPA primarily maxes out at 3.2 Mbps, with typical speeds ranging from 0.7 to 1.7 Mbps. The company is in the process of deploying faster 7.2 Mbps service, but this is currently limited to just a few cities: Charlotte, Chicago, Dallas, Houston, and Los Angeles and Miami. In terms of uploads, AT&T's 3G HSUPA network operates with typical speeds ranging from 0.5 to 1.2 Mbps, roughly two to four times faster than 0.3 Mbps theoretical maximum of the non-HSUPA capable iPhone 3GS. Not all of AT&T's 3G network supports faster HSUPA service."

Your take?

What other factors could be contributing to the iPhone 4's speed boost? If you're using the iPhone 4, what are you seeing in your speed tests? Jump into the discussion.

About

Jason Hiner is the Global Editor in Chief of TechRepublic and Global Long Form Editor of ZDNet. He is an award-winning journalist who writes about the people, products, and ideas that are revolutionizing the ways we live and work in the 21st century.

9 comments
enricog
enricog

Could you do the test again with the same SIM?

craig11
craig11

Two itemss: 1. Are they both running the same OS version? Diff OS could mean newer optimized TCP/IP stacks. 2. A newer faster processor in the 4 could mean faster checksum calculations, etc. This can make a huge difference with these lower horsepower processors running the OS, speed test software, and doing packet checksums in time-slices. No TOE cards here!

D T Schmitz
D T Schmitz

Are both 3G and 4 iphones HSDPA capable? I would tend to believe 3G is not. Thus the speed difference. Yes?

pscheer
pscheer

The increased bandwidth is encouraging. But I would be very interested to know how that affects the rate of dropped voice calls, especially in crowded cities like Los Angeles, where I reside.

jasonhiner
jasonhiner

I've updated the article. The iPhone got HSDPA in the iPhone 3GS and got HSUPA in iPhone 4. That's why I've suddenly noticed the big jump in upload speeds. The iPhone 3G (second generation iPhone) does not have either HSDPA or HSUPA.

XnavyDK
XnavyDK

lack of voice (talking capability) increases the ability to receive extra bandwidth because you have to hold it sidways with one leg over your shoulder to talk because its your fault its secondary purpose is to teach you flexability with your tongue stuck to the back plate for improved reception? change the name to IctwacSSid or I cant talk worth a crap small screened internet device. its no longer a phone, its just a mini Ipad? Oh the circle of life.

RoundTheBlock
RoundTheBlock

TCP tuning, leveraging the iPhone 4's additional memory and processor speed, is the likeliest cause of higher download speeds. My iPhone 4 scores far higher 802.11 speeds (above 13.5 Mbps) in side-by-side tests against the iPhone 3 (4.5 Mbps). Antenna design is likely irrelevant since they're within 30 feet of the base station with maximum signal strength showing on the display. My 802.11 a/b/g/n base station connects to a 35mbps / 35 mbps FiOS broadband connection. Haven't tried a packet capture yet, but it's likely the TCP windowsize is 4x larger. This can make a huge difference on high-latency cell data connections.

XnavyDK
XnavyDK

your holding it wrong? you should hold it how the applenazi's tell you or they will brick it for you, BAD Izombies BAD. I think your supposed to hold it perpendicular to the top of your head facing due east for voice reception. Due west for data with the device near your mouth for optimal tongue placement

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