NSN throws down gauntlet on smartphone signalling burden

Most infrastructure vendors are failing to address the signalling burden placed on 3G mobile networks by high end smartphones, according to Nokia Siemens Networks (NSN).

The German-Finnish JV says it has implemented a solution to the problem in its own products based on 3GPP standards and has accused its competitors of overlooking the fix.

“We know what an iPhone can do to an Ericsson base station,” Michael Matthews, head of strategy and business development at NSN told telecoms.com. “It can kill it.”

The correlation between smartphone penetration and signalling burdens was highlighted recently on telecoms.com in this feature. Some estimates suggest that for every bit sent or received a smartphone generates eight times more signalling than a laptop connected to the network with a dongle or embedded chip.

A subscriber using a laptop will likely consume more raw bandwidth than a smartphone user. But the greater volume of smartphones in the market – and the behavioural pattern of those terminals – means that the signalling traffic they produce far outstrips that generated by laptops.

While laptop connections can be kept open as they are often plugged into the mains (or otherwise powered by substantial batteries), smartphones do not have the battery muscle to remain truly ‘always on’. In order that they can give the impression of being so, however, handset vendors have designed smartphones to repeatedly awaken themselves from their idle modes to ping the network for updates before putting themselves back to sleep.

Many of the most popular smartphone applications, social networking and email solutions chief among them, require constant updates from the network. Each update, according to Phil Twist, head of marketing and communications for Network Systems at NSN, can generate 21 signalling messages, which roughly equates to the network usage required by a voice call. With a smartphone typically updating every one or two minutes, he told telecoms.com, the signalling traffic is comparable to 1,000 voice calls each day.

“The reason we’re claiming we have an answer here is because of an intermediate idle state called Cell-PCH. This uses the paging channel and requires only four signalling messages back and forth across the network to do that ping for updates. And it has similar background battery power consumption to the idle state, which is less than 5 milliamps.”

Read the full interview with Michael Matthews, head of strategy and business development at Nokia Siemens Networks

This translates into an 80 per cent reduction in signalling traffic, said Twist, and an improvement of up to 100 per cent in standby battery life for the smartphone.

The Cell-PCH software feature is not mandated by 3GPP and NSN claims it is the only vendor to have implemented it voluntarily. To implement it retrospectively is a non-trivial exercise, Twist said, adding that the feature could save a ‘typical’ network in the region of €45m.

The firm has had the feature activated since 2007, he said, but it has only recently become relevant as smartphone usage and data consumption has started to cause problems for network operators.