What is VoLTE, and what do you need to use it?

In the telecommunications industry, VoLTE is known as Voice Over LTE. The service uses a fourth-generation GSM network (LTE) for high-speed audio and multimedia transmissions. 

LTE is a pure packet-switched network, while in previous generations (3G/2G), there were two separate networks for packet and circuit switching. This brings a new way for Voice calls to work where a virtual voice circuit needs to be set up over a packet network.

Before VoLTE, a mobile subscriber could only use the Internet for web browsing and other activities over a data network. The VoLTE opens new options for subscribers and network operators by providing multimedia services over a high-speed GPRS connection. The best part is that the operators are no longer required to maintain two distinct networks, one for data and another for Voice.

What is required for VoLTE?

You will need to check the following to be able to use Voice Call over an LTE network.

  • The network sim card you use supports the feature and is enabled by the mobile operator with your current plan.
  • The phone that you are using has the capability for VoLTE.
  • The network in your area is an LTE network.

What is VoLTE?

As we have talked about, it’s Voice over an LTE network. Because of the higher data speed, the new fourth-generation network can offer a much richer experience for Audio, Video, etc.

The SS7 network was used for Voice on older networks (3G or 2G). However, voice packets are transferred utilizing a dedicated E1/T1 connection with reserved bandwidth. But, for today’s needs for applications, it is insufficient.

With VoLTE, the connection can use an underlying channel with much higher bandwidth, which results in the possibility of High Definition(HD) video and audio calls.

What is the link between VoLTE and LTE?

With LTE, data speed is enhanced compared to the previous generations, but the call was still on a 3G network. When there is a voice call, the phone fallback to 3G, and after the call completion, it again switches back to 4G-LTE. It makes a temporary disconnect with the Internet service. With VoLTE, there is no such interruption.

Advantages of VoLTE-

  • The call connects much more quickly, and the call quality is much better because of the faster speed.
  • A mobile user can browse data and at the same time can talk to someone over Voice.
  • It brings more services as all have moved to the IP protocols for telephony.

Disadvantages –

It cannot work on a basic phone that does not have data capability at all. At least in some areas, a mobile operator must always set up a parallel network for Voice.

What does a subscriber need to do for VoLTE?

For a mobile subscriber, the phone should be VoLTE capable. If not, he has to upgrade the phone. Once you are sure that the serving mobile operator supports the feature and your phone, too, you need to enable it in the handset.

How to enable it on Android? 

What are the obstacles that a mobile operator must overcome to support VoLTE?

It looks like it’s straightforward to support the new calling feature. But it is not so—first, an operator upgraded to 4G-LTE from the previous 3G. Upgradation includes purchasing spectrum and deploying radio and wired network components. Newer network components bring new protocols. For example, the diameter is the new protocol in 4G roaming, while in 3G, SS7 was the protocol.

Now data is on with over 4G, but still, Voice uses 3G fallback. With Voice Over LTE, no more fallback will happen. But require new network components with additional protocols. IMSI is the core network for VoWifi. It uses Session Initiation Protocol and other protocols, e.g., GTP primarily.

Within IMS, the sim becomes ISIM, and it does on the IMS network attach for Voice Calls, SMS, USSD, etc.

Is WiFi calling is same as VoLTE?

It looks like both are IP-based, but on a network level, both are far apart. The WiFi network is a non-3GPP network that requires an additional ePDG to support WiFi Calling. While VoLTE uses the same 3GPP network.

In VoLTE, the data is consumed from the subscriber data bundle, while in WiFi, Calling data is used from the WiFi account.