This blog is by Gerald Reddig from the Networks business of Nokia.
Some of history’s most famous figures were renowned for taking brief naps during the day, including Thomas Edison, John F. Kennedy, Salvador Dali, Winston Churchill and Napoleon Bonaparte. Such ‘power napping’ is supposed to be a healthy thing to do. It’s said to ‘recharge our batteries’, help make us more effective. Smart people and smart devices have a lot in common.
Which brings us to something called LTE connected mode discontinuous reception (DRX for short). This 3GPP standard function puts smartphones connected over LTE ‘to sleep’ for short periods when they don’t need to send or receive data. This cuts overall power consumption and lengthens battery life for a better customer experience.
There are two sleep cycles that together comprise LTE connected mode DRX. The optional short cycle, typically lasting a few tens of milliseconds, kicks in when the device detects it has no data to transmit or receive. If, at the end of this sleep period, the device still does not have any data to send or receive, it goes back to sleep. This short cycle process repeats for a set number of times after which the device switches to a long cycle, sleeping for a few hundred milliseconds each time. Conserving even more battery resources, these longer cycles continue until the radio connection is finally released due to data inactivity.
Nokia’s tests of commercial smartphones and applications have shown that LTE connected mode DRX, which Nokia calls ‘LTE Smart DRX’, can reduce the energy consumed by a smartphone by as much as 86% for short background traffic activity. More realistically, a smartphone using multiple applications will see around 30% to 40% less energy use compared to when no connected mode DRX is applied. That’s an impressive gain in battery life. What’s more, the LTE connected mode DRX function is already available in the majority of LTE devices available on the market and is supported by Nokia’s commercially available LTE technology.
The length and frequency of the short and long cycles can be adjusted according to configurable network parameters. These can be tuned to match the mix of traffic in the network and customized for different quality of service (QoS) profiles, such as VoLTE. This is where Nokia’s Network Planning and Optimization (NPO) service can make a real difference. Using the results of testing and by analyzing network traffic, Nokia Smart Labs can recommend the sweet spot for the length of the LTE connected mode DRX sleep periods to ensure smartphone users enjoy the longest battery life possible without any noticeable effects on performance.
So there you have it – short sleeps really do help people and smartphones accomplish more for longer. And now that I’ve finished writing this, I’m off for a nap – please don’t disturb…
To share your thoughts on the topic, join the discussion with @NSNtweets on Twitter using #NSNperformance #mobilebroadband #LTE #3GPP #VoLTE #QoS.