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VoLTE, sometimes known as HD Voice, improves call quality, extends your mobile device’s battery life, and enables simultaneous calling and browsing.

But what is VoLTE, and why is it important?

Below, we explain how VoLTE works, list the benefits it offers, and outline the differences between VoLTE and VoIP. We’ll also tell you how to enable VoLTE for Apple iOS and Android mobile devices.


What Is VoLTE?

VoLTE (Voice Over Long Term Evolution) is a telecom technology that uses 4G LTE data networks to facilitate VoIP voice calls on smartphones, tablets, and other mobile devices.

While VoIP technology relies on a VoIP-enabled desk phone or broadband internet connection to make/receive calls, VoLTE transmits voice data exclusively via wireless cellular networks. VoLTE is only accessible on mobile devices with GSM gateways (SIM cards) installed–so it doesn’t work on desktop computers or deskphones.

Because the 4G LTE network has a much higher bandwidth than 3G and other standard cellular networks, VoLTE provides faster download speeds, a higher quality of service, and enables web browsing during active calls.

Note that VoLTE calls are not the same as Wi-Fi calls, as they don’t require anyone on the call to connect to a Wi-Fi network. Vo5G (voice calling via the 5G network, not the LTE network) is currently in development, and will only improve VoLTE voice calling when fully deployed.

To summarize, VoLTE: 

  • Is a type of VoIP uniquely designed for LTE
  • Facilitates voice calls over mobile 4G LTE networks instead of a fixed phone line, broadband internet connection, or Wi-Fi connection
  • Is only for mobile devices with SIM cards



How Does VoLTE Work? 

VoLTE works by transmitting voice data packets via the 4G LTE mobile network–not via standard Wi-Fi or broadband Internet connections like VoIP.

VoLTE is based on the IMS architectural framework, a type of multimedia protocol for transmitting data packets over the Internet (IP network) as opposed to transmitting data packets via circuit switching.

The complete process of how VoLTE works is incredibly complex and involves several different gateways, servers, and interfaces.

To summarize, VoLTE works by:

  1. Breaking up voice audio into smaller data packets
  2. Establishing an end-to-end connection between the caller and the recipient(s)
  3. Using the 4G LTE mobile network to send voice data packets to their destination via a dedicated line that prioritizes voice data packet transmission above all other data types
  4. Quickly re-assembling the data packets at the destination and delivering HD call quality

As is evident, the process of data packet switching is similar in VoIP and VoLTE protocols. Both VoIP and VoLTE break up/compress voice audio into smaller data packets–but VoLTE packets are smaller and require less bandwidth to reach their destination.

Unlike VoIP, VoLTE:

  •  Transmits voice data packets via the LTE network
  • Transmits voice data packets on a separate radio frequency (dedicated line) to maintain the highest Quality of Service (QoS)
  • Prioritizes voice data packets over all other types, meaning fewer dropped calls and a higher overall call quality.



The below comparison table outlines the most important differences between VoLTE and VoIP.

Compatible Devices Mobile devices with LTE connectivity (smartphones, tablets, wearables, IoT devices, etc.) Desktop computers, VoIP phones, smartphones, tablets, laptops, and other mobile devices with or without SIM cards
Connection Type  4G LTE cellular networks
  • Web-based Internet connection (broadband or Wi-Fi)
  • PSTN-connected PBX systems
Data Transmission Process
  • Transmits voice data packets via the LTE mobile network
  • Creates smaller data packets than VoIP
  • Transmits voice data on a dedicated line to prevent dropped calls
  • Prioritizes voice data packets over all other data transmission
  • VoIP codecs convert and compress voice audio to small data packets
  • These data packets travel to the call recipient via an Internet connection, where they are reassembled and played to the recipient was originally spoken
  • Transmits data on a first-come, first-served basis
Audio Codecs
  • Narrowband Adaptive Multi-Rate codec (AMR-NB)
  • Wideband Adaptive Multi-Rate codec (AMR-WB/G.722.2/HD Voice)
  • Opus codec
  • G.711-G.722 codecs
  • Wideband Adaptive Multi-Rate codec (AMR-WB/G.722.2/HD Voice)
  • G.729 codec
Call Quality
  • HD voice calling thanks to a high-speed 4G LTE network that prioritizes voice data and frees up bandwidth
  • Smaller data packets mean faster downloads/data transmissions
  • Impacted by the strength of your Internet connection and available bandwidth
  • VoIP problems like jitter, latency, packet loss, and choppy audio may occur
  • Most VoIP providers offer HD voice, background noise suppression, and automatic bandwidth adjustment
Network Reliability
  • HD call quality is only available between two VoLTE-enabled devices (if not, both callers switched to standard audio quality)
  • HD call quality only available inside areas with 4G LTE service/coverage
  • Dependent on Internet connection strength and the provider’s overall network reliability
  • Look for VoIP providers offering 24/7 network monitoring, redundancy, and backup power sources
  • VoLTE calls are included in your smartphone minutes/plan at no additional cost
  • Standard roaming charges may apply to roaming VoLTE calls if the connection to the original IP network is lost
  • Smartphone plans cost an average of $144/month
  • Unlimited domestic VoIP calling is included in most monthly VoIP phone system costs, which usually range from $15-$30+/user/month
  • VoIP eliminates the cost of domestic long-distance calling
  • Some VoIP providers offer pay-as-you-go pricing


How to Use VoLTE on Your Phone

Below, we’ll outline how to enable VoLTE for your iOS and Android devices. The ability to turn on VoLTE varies by carrier and is automatically enabled for most 5G mobile devices.


How to Turn On VoLTE For iOS Mobile Devices

Note: VoLTE is automatically enabled on iOS 5G mobile devices using 5G, and can’t be turned off.

  1.  Go to “Settings” and select “Cellular” (“Mobile Data” on some models)
  2. Click on “Cellular Data Options” (“Mobile Data Options” on some models)
  3. Select “Voice & Data” then choose “4G VoLTE on” (slide to enable VoLTE on some models)

enable volte iphone


How to Turn On VoLTE For Android Mobile Devices

  1. Go to “Settings” and select “Network & Internet” (“Connections” on some models
  2. Click on “Call” (“Cellular Networks,” “Mobile Data,” or “Mobile Network” on some models)
  3. Click on “Preferred Network Type” (“Network Mode” on some models)
  4. Select “LTE/5G/4G”, then enable “VoLTE” (“HD Voice” or “Enhanced Calling” on some models)

enable volte android


The Benefits of VoLTE

  • High Call Quality with HD Voice: VoLTE cuts down on the number of  dropped calls by sending voice data over a dedicated line and delivers HD audio thanks to higher speeds and less bandwidth usage
  • Additional Communication Channels: VoLTE provides direct HD video calling and SMS texting without requiring users to download a third-party app
  • Increased Mobility and Flexibility: Users can make/receive business phone calls on their personal/preferred devices and aren’t tied to a single location
  • Cost Savings: VoLTE works with existing mobile devices, eliminating the need to purchase new hard phones and additional equipment. VoLTE is also already included in your monthly cell phone plan, and does not incur any additional costs.
  • Simultaneous Calling and Browsing: VoLTE enables users to access the Internet/watch videos, etc. while on active phone calls
  • Longer Battery Life: 4G is more efficient than 3G and other outdated networks, meaning it won’t drain your mobile devices’ batteries


VoLTE Challenges and Limitations

  • Only available in areas with a strong 4G signal
  • Requires all parties participating in a call to use VoLTE-enabled devices
  • Older mobile devices and some carriers may not be compatible with 4G/VoLTE
  • May require manual setup
  • Vo5G implementation is still in process
  • Usually not available for international calls



Below, we've answered popular VoLTE FAQs.