Dialogic Blog

VoLTE Performance

by Jim Machi

Jan 6, 2015 10:08:21 AM

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One of my predictions for 2015 related to VoLTE and Value-Added Services (VAS) starting to appear in relation to VoLTE.  I wanted to give a little background on why I said that.  It basically comes down to VoLTE working.

In the summer there was some buzz made when Signals Research Group put out a paper about VoLTE performance. There is also very excellent information on this study on the GSA website in the October 14th area, if you are registered and can get access.  The study tells a good story, such as call quality as measured by MOS score (3.8) “greatly exceeding” 3G voice and being “measurably higher” than Skype (3.4). This is not surprising given use of HD Voice with VoLTE.  Call setup times are “nearly twice as fast” as 3G.  From a network resource perspective, there are “substantially fewer” than Skype required, which results in longer battery life.  All of these tell a great story about VoLTE.

In November, Ericsson also released a study of VoLTE compared to 3 OTT voice services. The MOS scores and speech delay were marketly better with VoLTE. The Ericsson reports goes on to say “In summary, VoLTE is a real-time telephony service managed over the operator network end to end (IMS, EPC, LTE with policy control), and the service is always prioritized over all other services. OTT VoIP services run as best-effort data services over the LTE network and are thus mixed with all other data traffic. The OTT services can thus sometimes have high quality, and sometimes very poor quality, while VoLTE offers a high and stable quality throughout the calls.”  That is kind of common sense as well, but often forgotten.  The Ericsson document also points out improved battery life.

VoLTE is here to stay. There is a lot more information to obtain such as VoLTE roaming (which is just starting).  Additionally SRVCC (Single Radio Voice Call Continuity) / VoLTE handover needs to be proven.  I’ll keep an eye out for that.

Topics: VoLTE/VoWifi & IMS