Batteries are a drain on smartphone performance

Batteries stand charged with holding up the mobile internet, but SMP technology can combat their limitations, says Laurence Bryant

Battery performance is what stands in the way of making the smartphone most people's primary computing platform, says Laurence Bryant.

December 2009 marked the point where mobile data traffic volumes overtook voice, with 80 percent of mobile internet users demanding broadband access anywhere and at any time. But as mobile internet capabilities and consumer demand have increased, so has the strain on the battery life of the devices used to access the internet.

Consumer choice and design aesthetics have added to the technology demands, placing added pressure on device manufacturers who have less space for batteries.

Limiting factor
Optimising battery performance is crucial to the development of the mobile internet. Without improvements, battery life remains a limiting factor in trying to meet mobile users' increasing demands.

With the industry searching for new ways to meet expectations, a process called symmetric multiprocessing (SMP) is being adopted on mobile platforms. With SMP, multiple identical processors are connected to a single shared memory and controlled by a single operating system.

SMP treats multiple processor cores as separate processors, whereby any tasks can be moved easily between them. This balances the workload between the cores, resulting in lower power consumption and longer battery life.

The number of people who use their mobiles to access the internet is on the rise. According to GSMA Media Mobile Metrics, over 6.6 billion mobile web pages were viewed in the UK in December 2009. Facebook can be credited with 2.6 billion of those views, making the social network a key driver in mobile internet use in the UK.

That trend means mobile users now expect constant connectivity and the ability to view rich multimedia content. They also think smartphones should be able to offer similar internet performance to a personal computer.

Stress on functionality
To create a true internet experience, multimedia technology has evolved to the point where there is an increased stress on functionality, with users demanding content to be played on any device.

Mobile devices can be powered with high-definition viewing and gaming, modem connectivity, HTML 5 and vastly increased levels of data processing via the internet. Gone are the days when the mobile phone was primarily used to...

...make calls, send texts and perhaps play the odd game of Snake. Now they are high-power multimedia devices.

A result of the increasing availability of multimedia content, mobile and smartphone displays have become bigger, which also places a greater strain on power consumption.

There is continued pressure to increase the performance of handsets without jeopardising long battery life — and even a move to reducing their power consumption.

The added pressure means mobile devices now need to perform elastically, working at optimal levels in low-power states, such as when on standby or voice calls for long periods, but also to be able to perform in high-performance states, running complex content applications and delivering internet capabilities on demand.

Low-power technologies
Tracking the allocation of power distribution and continuing the development of more low-power technologies is crucial to meeting the new functionality expectations.


SMP technology will be used to combat the limitations of battery life, with multi-core processors delivering higher performance than a single core alone could achieve from the same power budget.

SMP allows slow-speed applications such as voice and text to run on a single core while multiple CPUs run the more complex applications required for fast browsing, watching rich multimedia content and receiving modem speed internet connections.

If we can continue to increase performance without adding to power needs, the potential for the smartphone to include the functionality of the personal computer can be realised, making the smartphone the primary computing platform.

Laurence Bryant is director of mobile solutions at microprocessor design company ARM.


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