iPhone Troubles Might Go Beyond Signaling

What's ailing the AT&T Inc. (NYSE: T) 3G network might not be fixed with the simple backhaul upgrade that the carrier is touting. But it's possible that boosting the signaling capacity, which has been flagged as an alternative answer, won't do the trick either.

It depends on whom you talk to, of course. Nokia Networks claims it's got the surprisingly simple answer for the signaling problem, but Alcatel-Lucent (NYSE: ALU) tells Light Reading that AT&T's problems are probably multifaceted and can't be fixed in one blow.

The issue at hand is the rate of dropped calls and bad connections on the 3G network, a problem that's caught fire since Apple Inc. (Nasdaq: AAPL) released the 3G iPhone. (See AT&T Mobile Boss: NYC & San Fran Are 'Underperforming' and AT&T to Spend $2B More on Wireless in 2010.)

And now, Apple has released the iPad, at least in the United States, leading to concerns that things might get worse. (See Apple to Ship New 3G iPads by May 7, Will the Apple iPad Crush 3G Networks?, and Apple Delays International iPad.)

Ars Technica mentioned the signaling factor in February. The iPhone frequently disconnects its data connection in order to prolong battery life. But that means that to do tasks like check for new emails, the device has to reintroduce itself to the network, restarting the secret handshake that requires lots of signals traded back and forth. The result is the equivalent of thousands of new phone calls, and it could be overloading the network's signaling capacity. (See What if Capacity Isn't AT&T's iPhone Problem?)

Folks at the 3rd Generation Partnership Project (3GPP) predicted this problem, it turns out, and there's a standardized, years-old fix for it, according to Phil Twist, Nokia Siemens's head of network systems marketing and communications.

It's called the paging channel, or Cell PCH, and it's been in Nokia Siemens gear for five years, with more than 50 operators using it, Twist says. It's just a simpler standby mode, one that uses fewer signaling calls to ping the network.

"It's a simple software feature that reduces the overall congestion of the network by a factor of three and doubles the user's battery life," Twist says. "It's been in every handset shipped since 2007."

But as Twist noted in this message board post, and as he explained to Light Reading at the time, equipment vendors haven't bothered to implement it. Equipment vendors other than Nokia Siemens, that is. Instant publicity blast!

So, it would appear the signaling problem will remain unaddressed unless AT&T's radio network controller (RNC) vendors -- Alcatel-Lucent and Ericsson AB (Nasdaq: ERIC), according to Heavy Reading analyst Gabriel Brown -- can provide the software upgrade to incorporate the paging channel. (This might be a convenient point to mention that AT&T declines to comment on the whole signaling issue.)

But wait. AlcaLu is quick to point out that signaling isn't likely to be the only thing affecting calls on AT&T's network.

A rainbow of troubles
Networks are as different as fingerprints, and there isn't always one specific cause of bad service, says Mike Schabel, an Alcatel-Lucent general manager.

While he won't talk about AT&T specifically, Schabel says there's a long list of problems he's seen in general: security problems introduced by laptops, wireline applications that prove inefficient on a wireless network, or plain old misconfigurations. "There's never been, in any network I've gone to, the same root cause," he says.

As you'd expect, AlcaLu claims it's got just the tool for the trick: the 9900 Wireless Network Guardian. It's a software package that runs on "semi-custom" hardware at one location in the network, Schabel says. From there, it measures each network element's contribution to bad service, letting operators decide where to prioritize their corrections.

Schabel works on test gear like the 9900, not wireless gear, so he doesn't have a comment about whether AlcaLu will be implementing Cell PCH. But he does have an opinion: He thinks Cell PCH, in any network, is one small fix applied against a group of big problems -- not a cure-all, in other words.

So, maybe AT&T does need to add more capacity and more backhaul to its 3G network, and maybe it does need to cool down the signaling chatter among smartphones. But if Schabel's world view is right, neither fix is going to put the iPhone Effect to rest.

— Craig Matsumoto, West Coast Editor, Light Reading

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