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What Is the Difference between VoIP and VoLTE?
February 8th, 2016

What Is the Difference between VoIP and VoLTE?

Bill Gaskill

VoIP (Voice over Internet Protocol) and VoLTE (Voice over Long Term Evolution) each uses packets to send voice and data over the Internet. Each lets you make calls over the Internet. However, the way...

VoIP (Voice over Internet Protocol) and VoLTE (Voice over Long Term Evolution) each uses packets to send voice and data over the Internet. Each lets you make calls over the Internet. However, the way the Internet carries the packets and the type of network necessary to leverage the capabilities of VoIP and VoLTE are different.

The differences between the two include:

  • Using 3G or 4G service
  • QoS (Quality of Service) component
  • Radio frequency or SR-VCC (Single Radio Voice Continuity) IP (Internet Protocol) Multimedia Subsystem (IMS) requirement
  • HD Voice

VoIP basics

VoIP sends voice packets over the Internet the same way it sends data packets. Your phone transmits the voice packet, and the packets get shuttled along the Internet by-ways. There is no difference in the way the voice packets get sent. Data or voice has the same priority.

VoLTE basics

VoLTE is also called 4G LTE since it must use 4G networks to transmit its data packets. VoLTE packets have three times more voice and data carrying ability using a 4G network. VoLTE also has built-in QoS components.

Long Term Evolution

The LTE portion of the VoLTE acronym refers to Long Term Evolution. It is a transmission standard that carriers and proponents use when referring to increased capacity and speed for wireless data networks. According to technopedia, LTE, “…refers to a standard for smooth and efficient transition toward more advanced leading-edge technologies to increase the capacity and speed of wireless data networks.”

LTE is the pathway followed along 4G networks.

VoIP and VoLTE: The 3G and 4G requirements

Carriers boast of having 4G or fourth generation networks. The 3G networks, which replaced 2G, allowed carriers to handle much larger data formats such as video and music packets.

The 4G connection standards require a minimum of 100 megabits per second. This latest connectivity evolution is much faster than the previous iterations.

VoIP uses 3G or 4G. VoLTE can only use 4G.

Quality of Service: The fundamental difference

The basic difference of VoLTE compared to VoIP is that VoLTE requires a QoS component. Voice packets for VoIP get sent along Internet nodes and are treated no differently than any other data. VoLTE uses IMS and a separate radio frequency to help maintain the quality of the VoLTE transmission.

QoS seeks to control jitter, provides dedicated bandwidth, and seeks network priority. QoS also improves performance by addressing latency, error rate and uptime problems.


If a user leaves an LTE coverage area, this is where the SR-VCC component of VoLTE activates. SR-VCC functions by connecting to the LTE and legacy network at the same time. The radio frequency uses the IMS framework to make this happen.

IP Multimedia Subsystem (IMS) framework

The IMS framework facilitates packet communications through Internet Protocol using landline or wireless. VoLTE uses the IMS to assist with the way it transmits voice and data packets.

High Definition (HD) Voice

VoLTE can also support High Definition Voice. LTE networks encode directly the wideband audio necessary to carry the HD Voice. The IMS framework lets VoLTE transmit the HD Voice.

Theoretically, the quality of VoLTE calls compared to regular VoIP calls is better. Practically, however, you can only make HD Voice using an HD Voice device at both ends. If one device does not have HD capability, the voice quality for the caller and receiver will not have high definition sound.

Other Differences

Since VoLTE uses fewer resources and has simpler compacting ability for the data packets, networks and handsets, these items consume use less energy with VoLTE. This provides greater battery life for each.

VoLTE calls take less time to connect than a 3G call.


The essential difference between VoIP and VoLTE is the technology. VoLTE is specially designed for 4G, LTE networks. VoIP uses both 3G and 4G equally well.

Some of the newer smartphone technologies, like the iPhone 6, are built to take advantage of VoLTE technology.

Whether or not all devices and providers migrate to 4G LTE and whether or not VoLTE becomes the standard for new technology in the future remains unknown.

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