AT&T Wireless confirmed its plans to begin throttling data speeds for its heaviest data users, beginning October 1.

The new policy will reduce the network speed of the top 5 percent of smartphone data users with unlimited data plans. The speed will be restored at the beginning of the next billing cycle, but of course it will get slowed down again should data usage reach that top tier again.

“These customers on average use 12 times more data than the average of all other smartphone data customers,” an AT&T Wireless statement said. “This step will not apply to our 15 million smartphone customers on a tiered data plan or the vast majority of smartphone customers who still have unlimited data plans.”

The company suggests any customer concerned about being throttled could switch to a tiered plan, under which they would end up paying more for the data they use but never get their speeds reduced.

AT&T Wireless suffered network congestion and failures after it began offering Apple’s iPhone. With the iPhone 5 expected out within the next few months, discouraging unlimited access may be a strategic step to avoid a recurrence of those problems.

The company, while not addressing the iPhone issue directly, did say it hoped the new policy would result in better service for the majority of customers. “Even as we pursue this additional measure, it will not solve our spectrum shortage and network capacity issues,” AT&T took the opportunity to add. “Nothing short of completing the T-Mobile merger will provide additional spectrum capacity to address these near term challenges.”

There is no defined amount of data that will definitely put a customer in that top 5 percent, but 9to5mac reports, “We’ve been told that 12,000 emails, 12,000 website views, 4 streaming movies and 5 hours of streaming music will start to put you close to that upper range of usage.”

Related Links:

AT&T Wireless statement –

9to5Mac –