Apple Inc. has added a feature in the latest iOS operating system update that will reduce the amount of signaling traffic that the iPhone 4 generates on operators' mobile data networks, according to lab tests conducted by Nokia Siemens Networks.

Tests at Nokia Siemens' Smart Lab in Espoo, Finland, show that Apple's iOS 4.2 supports a newly standardized version of a state transition feature called fast dormancy, which is part of the 3rd Generation Partnership Project (3GPP) Release 8 set of specifications. This feature, also called network-controlled fast dormancy, basically sets parameters on how, and how often, a smartphone switches between idle and active modes while also preserving device battery life.

Apple's support of this feature is important because it could help operators to better manage signaling traffic loads, which have crippled some 3G networks. (See What if Capacity Isn't AT&T's iPhone Problem?, 02 Felt iPhone Crunch Too, iPhone Troubles Might Go Beyond Signaling, and AT&T: Don't Choke Us.)

As Light Reading Mobile reported recently, mobile operators have mandated that smartphone vendors support this new feature. Operators felt their networks were being overwhelmed by heavy signaling traffic, as many smartphones used a pre-standardized version of fast dormancy to save handset battery life by disconnecting data sessions frequently. Every time a smartphone sets up and breaks down a data session, it has to chat to the network, and that creates excess signaling traffic. (See Operators Fight Back on Smartphone Signaling.)

According to Nokia Siemens' mobile broadband marketing manager, Leslie Shannon, the new fast dormancy feature update will only apply to the iPhone 4. The tests in Nokia Siemens' lab showed that Apple's implementation is compatible with Nokia Siemens network equipment.

Nokia Siemens notes that Nokia Corp. has adopted a proprietary technology that imitates network-controlled fast dormancy. In addition, Research In Motion Ltd. (RIM) has said that it expects its handsets to support the standardized fast dormancy feature in the first quarter of next year.

"Having handsets support a standardized network-controlled fast dormancy mechanism will help operators manage the signaling load from smartphones and run more efficient networks," says Heavy Reading senior analyst Gabriel Brown. "Several network vendors have noted support for this feature in the iOS 4.2 release. It’s very positive how quickly the industry is working to optimize fast dormancy before it becomes a major problem."

For this feature to reduce excessive levels of smartphone signaling traffic on a broad scale, network equipment vendors will have to include it in their equipment as well and interoperate with the handset maker's implementations. (See NSN, Qualcomm Tackle Smartphone Performance.)

— Michelle Donegan, European Editor, Light Reading Mobile