Voice Over LTE – VoLTE is the technology which will drive the future of voice call over next generation mobile networks and it will replace legacy circuit switched call technology. But recent studies made by Metrico Wireless give some scary results for mass implementation of VoLTE. The worst part is that VoLTE calls consumes more than twice battery power than traditional CS calls.

Every year smartphone battery is getting bigger and bigger. Some of the latest smartphones have the most powerful battery compared to last generation smartphones and it’s increasing at a rate of 14% per year. But still these larger batteries are not enough. The average device now has a dual-core processor, as many as five radios, a high-resolution display, one or more HD cameras, and multi-tasking apps, providing sophisticated new functions for subscribers—while increasing battery drain.

Metrico Wireless conducted studies in two different US cities comparing power consumption due to VoLTE on LTE network and they compared the results with same carrier’s CDMA network. Though Metrico Wireless did not mention the name of the operator, it is easy to guess as there is only one operator supports VoLTE in US.

MetroPCS is the only U.S. operator with a live VoLTE service and a commercially available handset. The 1540 milliamp hour (mAh)-battery on Metro’s sole VoLTE handset, the LG Connect 4G, also lines up with the battery capacity of the device Spirent tested.

The test was conducted for 10 minutes and average power consumption od 10 minute CS call over CDMA was 680 milliwatts (mW) and in the same time 10 minutes VoLTE call over LTE network consumed 1358 mW. Spirent estimated that on a full charge, its test smartphone could support 502.6 minutes of talk time using CDMA only, but the same charge would only deliver 251.8 minutes of talk time using VoIP on the 4G network. And that’s with all other data communications turned off.

If this proves to be typical for VoLTE handsets, it will be a big problem. The battery life of the first generation of LTE smartphones was atrocious, and handset vendors have tried to address the problem by slapping fat 3000+ mAh power cells onto their phones. Some carriers are already reluctant to embrace VoLTE since they can still squeeze plenty of life out of their 2G and 3G voice services. If VoLTE proves to be a battery killer, they will be even less inclined to move mobile voice into the IP age.

There are some good news about VoLTE though. Metrico Wireless found that for Multi-RAB scenarios when both Data and VoLTE are active at the same time, LTE performed better than CDMA but with a small margin.

The conclusion is that a lot need to be improved in VoLTE in terms of power consumption.