Sales of smartphones are expected to overtake those of laptops in the next 12 to 18 months as the mobile phone completes its transition from voice communications device to multimedia computer.

Convergence has been the Holy Grail for mobile phone makers, software and hardware partners, as well as consumers, for more than a decade.

And for the first time the rhetoric of companies like Nokia, Samsung and Motorola, who have boasted of putting a multimedia computer in your pocket, no longer seems far fetched.

"Converged devices are always with you and always connected," said Olli-Pekka Kallasvuo, Nokia chief executive at last week's Mobile World Congress in Barcelona.

Last year Nokia sold almost 200m camera phones and about 146m music phones, making it the world's biggest seller of digital cameras and MP3 players.

In the coming year the firm predicts it will sell 35 million GPS-enabled phones as personal navigation becomes the latest feature to be assimilated into the mobile phone.

Form and function

Nigel Clifford, chief executive of Symbian, said: "All of those single use devices - MP3 players, digital camera, GPS - are collapsing onto the phone."

"We are going past the point where this was a phone with a few other things," he said.

Symbian's operating system shipped on 188 million phones last year and a third of those came with GPS.

"We see mobile phones evolving into multi-functional devices that now support consumer electronics, multimedia entertainment and mobile professional enterprise applications; all converging," said Luis Pineda, from mobile phone chip firm Qualcomm.

Convergence is being driven by a combination of software, services and hardware.

The first phones powered by a chip running at 1Ghz will hit the market later this year, seven years after the first desktop chip broke the gigahertz barrier.

Qualcomm's 1Ghz Snapdragon chipset will debut inside a number of handsets, including some from Samsung and HTC

"It's a first in the industry for a wireless chipset," said Mr Pineda.

As well as raw horsepower Snapdragon also features a dedicated application processor, as well as the ability to handle 12 megapixel digital photos and up to 720p high definition video imaging.

Mr Clifford from Symbian said the mobile industry had to deliver multi-function devices which did not compromise.

He said: "When we look at what is collapsing on to these devices and people's expectations with their experiences on single-use specialized devices there is going to be rising expectations."

Chip shop

More than 90% of the world's mobile phones are powered by technology created by British firm Arm. It designs chip architectures that it licenses to semiconductors makers such as Qualcomm and Broadcom.

Ian Drew from Arm said future mobile phones demanded ever more processing power.

But building chips with greater processing was not a straightforward, he said.

"If you look at a typical phone the first thing you have got to do is get within the half a watt envelope.

"It needs to get into your pocket. And there's no fan. It needs to work for days rather than hours."

He added: "When you start adding multi media experiences - such as 3D graphics, video, and games - there are two ways to do that: you can get bigger and bigger processors or you have multi core where you can switch off a processor when you don't need it."

Arm is demonstrating a chip architecture, called Coretex A9, that will offer four cores, or processors, on a single chip.

Symbian has been working with Arm on future uses for multi-core mobile phones.

"You can use massive amounts of processing if you need it. But if you don't you can power down the cores that aren't required," said Mr Clifford.

Symmetrical Multi Processing will drive the next generation of applications on a phone, he added.

"Silicon vendors are looking very seriously at how they integrate SMP."

Mr Clifford added: "The future of the internet and computing applications is not going to be in the home or at the office; it's going to be mobile."

He said gaming would be the next feature to collapse into phones.

"That is one of the next single usage devices that will start feeling the pressure from the mobile device," he said.

3D graphics acceleration is becoming standard on many of today's mobile phones and specialists like Nvidia have joined the market.

Mr Clifford said today's most powerful mobile phones, such as Nokia's N96 and NTTDoCoMo's 905 series have the same power as a laptop from 2000.

Nvidia's APX 2500 chip has enough 3D graphics acceleration to handle Quake 3, a PC game from 1999, on a mobile phone.

Handset owners were also beginning to expect the same online experience they have on their desktop PCs on their mobile phones.

"Web 2.0, social networking and video sharing; that's a real driver of horsepower," said Mr Drew from Arm.

He added: "But you need to be able to get data in. The next generation of mobile phones need high performance radios - they will have high data rates that will enable this content to be streamed to you."

Symbian is working on technology called Freeway to give phones the ability to move seamlessly between wireless networks, like wi-fi and cell networks like 3G and 4G.

"We don't want people to feel the mobile web is a second class experience."

Leading-edge phone technology on show in Barcelona