Enhanced Voice Services (EVS)


Full-HD Voice quality for mobile telephony


EVS is especially designed for VoLTE (Voice over LTE) services. It enables phone calls with Full-HD Voice quality, bringing call fidelity up to the same level as today’s other digital media services. Integrating state-of-the-art speech and audio coding technology, EVS removes the limitations of bandlimited and voice-centric codecs that were previously used in mobile communications.

The GSMA has nominated EVS as the mandatory audio codec for superwideband transmissions via VoLTE (please also see "Official Document IR.92 - IMS Profile for Voice and SMS").




...enables Full-HD Voice audio quality

EVS delivers unprecedented quality for speech, background music and mixed content for narrow-, wide-, superwide- and full-band services, outperforming the audio quality of today’s mobile phone calls and over-the-top communication services.


...delivers high efficiency and versatility

EVS offers a wide range of bit rates from 5.9 kbit/s to 128 kbit/s, allowing service providers to optimize network capacity and call quality as desired for their service. Bit rates for narrow- and wideband start at 5.9 kbit/s, while superwideband Full-HD Voice audio quality is supported from 9.6 kbit/s on. EVS also significantly improves the audio quality over legacy codecs at popular mobile bit rates such as 13.2 kbit/s and 24 kbit/s.


...ensures a reliable service

Mobile network services such as VoLTE or Voice over WiFi can be affected by packet loss issues, resulting in a negative impact on speech intelligibility. EVS utilizes unique concealment techniques to minimize the impact of packet loss caused by adverse conditions in the transmission channel.


...is backward-compatible to existing VoLTE services

The codec’s integrated AMR-WB interoperability mode eliminates the need for a separate AMR-WB implementation allowing the signal to quickly switch between VoLTE (4G) and circuit switched networks (3G) when network conditions warrant a transition.


There are several operators worldwide which have already launched EVS powered VoLTE services. These include:

  • NTT DoCoMo
  • T-Mobile USA
  • Vodafone Germany
  • Korean operators

Please see the following list for examples of smartphones that support EVS:

  • HP Elite x3
  • HTC One M10
  • LeTV Le Max Pro
  • LG G5
  • Samsung Galaxy Note 5
  • Samsung Galaxy S6
  • Samsung Galaxy S6 edge
  • Samsung Galaxy S7
  • Samsung Galaxy S7 edge
  • Sharp AQUOS Zeta
  • Sony Xperia X Performance
  • Vivo Xplay5
  • Xiaomi Mi5


Please note: Starting the video transfers usage data to youtube.

The Next Generation of Mobile Call Quality

Europe´s most important trade show of the mobile domain ended a few days ago in Barcelona: the Mobile World Congress. Fraunhofer IIS provided visitors the opportunity to experience the future of mobile call quality with the recently finalized 3GPP communication codec “Enhanced Voice Services” (EVS) designed specifically for Voice over LTE (VoLTE) and Voice over WiFi (VoWiFi) services.