Voice calls over 4G LTE networks are battery killers

Every mobile carrier wants to replace their old voice services with new VoIP-based systems utilizing their 4G networks, but it looks like they’ve got some big kinks to iron out in the technology first.

Wireless testing and measurement vendor Spirent Communications has identified a big problem with voice over LTE (VoLTE): it consumes twice as much power as a traditional 2G call, which could have big implications for mobile phone battery life. Metrico Wireless, a radio field testing company Spirent acquired in September, conducted voice trials on a commercial VoLTE-enabled network in two U.S. cities, comparing the power consumption of VoIP calls made over LTE against the power used by the same carrier’s CDMA systems. Spirent-Metrico didn’t name the carrier, but it’s not hard to guess. 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 results of those tests should give carriers and consumers pause. The average power consumption for a 10-minute CDMA circuit-switched call was 680 milliwatts (mW) while the average consumption for a VoLTE call of the same duration was 1358 mW. That’s double the power drain. 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.