AT&T is rushing to rollout a major upgrade to its 3G mobile data service in anticipation of a tenfold increase in network traffic from new iPhone hardware expected to go on sale in June, according to a vendor source.

Apple’s exclusive mobile service provider in the US has already laid out plans to upgrade its 3G data network on multiple fronts. Last month AT&T CEO Ralph de la Vega said in an interview that “we have the infrastructure capability to go to 7.2 [Mbit/s], and we’ll have the capability to go 14.4 and 20 in the next couple of years, so I think there’s coverage we’re going to improve, there’s quality we’re going to improve, and there’s speed that’s also going to get improved.”

The current iPhone 3G only supports a maximum of 3.6 Mbit/s, so AT&T’s plans to achieve the full potential of its current 3GPP Release 5 network technology would require new iPhone hardware to fully exploit. However, the wireless link between the phone and the cell tower is only part of the network speed equasion. Another factor is the speed and capacity of AT&T’s network backbone.

Reports have already indicated that about half of the mobile data traffic AT&T handles is related to the iPhone. Web statistics from Net Applications also show that more than two thirds of all US mobile web data traffic is used by the iPhone, which also makes use of WiFi.

But AT&T’s upgrade is expected result in moving even more data across its mobile network, with one source saying they “expect [to] see 10 times as much data traffic as they are now experiencing” once new iPhone hardware is released this summer.