LTE Power Challenges Are Significant — and Solvable

Device power – or, more precisely, the threat of running out of it too quickly – has been a significant concern of the mobile industry for years. Those concerns are heightened as LTE takes root.

This is something to worry about considering the speed at which LTE is expanding. (AT&T, for instance, said this week that it will begin service to 77 markets this summer.) This is especially true, as Kyle Wagner points out in this freewheeling commentary at Gizmodo, in an era in which expansive features and good looks generally stand in the way of power efficiency. In other words, the marketing department is winning.

This week, a company called Quantance raised $12 billion in series D funding from investors including the TD Fund, Granite Ventures, InterWest Partners and DoCoMo Capital, according to PR Newswire. Quantance’s basic approach is called envelope tracking. It is described at Inc. by CEO Vikas Vinayakat as continual adjustments of power amplifier voltage to ensure efficiency.

It’s no surprise that the technology is garnering support. Last month, GigaOm’s Kevin Fitchard discussed the power requirements of Voice over LTE (VoLTE), which is a potential killer app that is on the fast track to implementation.

There is both good and challenging news in the story. The challenge element is that VoLTE eats up a tremendous amount of power. A big part of the reason for this is that LTE is additive; devices have to support a backup standard since coverage for the foreseeable future at best will be spotty. The good news is that there are smart ways of doing this that haven’t been tapped into yet. This and the usual growth in efficiency that new technologies enjoy means that significant improvements are possible – and already have been noted:

Spirent recently performed a new batch of tests using Metro’s newest generation VoLTE handset, the LG Spirit 4G, and found that the current drain from a VoLTE call had dropped by 35 percent compared to LG’s first-generation VoLTE smartphone, the Connect. Improving power efficiency by 35 percent is a tremendous number when it comes to cellular battery life, which tends to measure progress in tiny increments. But there is still one big qualification to that good news: 2G is still a more power-efficient technology.

Neal Gompa at ExtremeTech discusses in great detail the ramifications of having to support two standards. The details are complicated, but Gompa sums it up nicely near the beginning of the piece:

The reason why LTE devices right now eat batteries for breakfast is because the network operators are forcing these devices into active dual-mode operation.

By this point, there has been enough new technology that it is clear that power consumption comes down over time due to both smarter and more efficient operations and technical tweaking. In other words, when it comes to the power requirements of mobility, necessity is the mother of invention.