Voice over LTE
VoLTE or Voice over Long-Term Evolution is an
To be able to make a VoLTE call, the device, its firmware, and the mobile telephone providers on each end, as well as the inter-carrier connectivity must all implement the service in the area, and be able to work together. VoLTE has been marketed as "
Overview
VoLTE is based on the
As of February 2019 there were 253 operators investing in VoLTE in 113 countries globally, including 184 operators with commercially launched VoLTE-HD voice service in 87 countries, up from 137 operators in 65 countries 12 months previously, according to data from the Global Mobile Suppliers Association.[4] By August 2019, these numbers had risen to 262 operators investing in VoLTE in 120 countries and 194 operators with launched VoLTE-HD voice services in 91 countries.[5]
Requirements
- Phone service provider has to enable the voice service on its LTE cellular network. Called "VoLTE profiles", it contains the necessary information, for each service provider, to enable VoLTE on the customer's equipment.
- Device manufacturers have to update their devices, for all providers all over the world, with each operator's profile.
- If the service provider of a mobile is present within the device, the operating system will automatically connect and enable Voice over LTE.
Encountered problems
There are several issues of the VoLTE deployment :
- All subscribers were not automatically eligible to VoLTE, it was firstly enabled for specific-subscribers only[6]
- Some providers had VoLTE only compatible with equipments sold by their shops
- Old LTE devices are not updated by their manufacturer, thus are not compatible[7]
- Emergency services encountered issues as being reachable in VoLTE[8]
- In USA, lot of M2M devices were not LTE-compatible[9]
- Lot of tourists has been surprised by being forced to acquire a VoLTE compatible phone
- Lot of second-range devices brands are not supported by cellular operators
- There is no possibility to "check" which operators in the world, are supported on a specific device
History
Beginning in August 2012,
In November 2014, Verizon and AT&T announced the companies are enabling VoLTE-to-VoLTE connections between their respective customers. VoLTE interoperability between Verizon and AT&T customers began in 2015. Testing and design were performed between both companies using third party networks such as Alcatel-Lucent.[13] This was stated to have been completed in November 2017.[14]
On July 11, 2015, SEATEL Cambodia announced the world's first commercial 100% VoLTE service without 2G/3G in Cambodia.[15][16][17][18][19]
As of 2020, almost all new phones for sale have the potential to support VoLTE.[citation needed]
On December 31, 2022,
Additionally, certain Verizon-compatible handsets were blocked from Verizon's CDMA network even before December 31, 2022, even if the device supported CDMA (for instance, unlocked devices with support for
Voice quality
To ensure compatibility, 3GPP demand at least AMR-NB codec (narrow band), but the recommended speech codec for VoLTE is Adaptive Multi-Rate Wideband (AMR-WB), also known under the trademark HD Voice after GSMA's certification program. This codec is mandated in 3GPP networks that are capable of 16 kHz sampling.[22]
In addition, many carriers and devices can use Enhanced Voice Services (EVS). This is an up to superwideband (20–16,000 Hz) or fullband (20–20,000 Hz) codec backwards-compatible with AMR-WB.[23] This codec is also known under the trademark HD Voice+, after GSMA's certification program.[24] GSMA has proposed to make EVS mandatory just like AMR-WB.[23] (Both the carrier(s), any interconnect and the two calling devices must be capable of using the codec for it to be used.) The AMR-WB+ codec has a wide bit-rate range, from 5.2 to 48 kbit/s. 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, so VoLTE does not ensure high call quality.[23]
Fraunhofer IIS has previously demonstrated an implementation of the AAC-ELD codec in VoLTE that they call "Full-HD Voice". It has not gained any standard status or real-world adoption.[25] They have since reused the term "Full-HD Voice" for EVS in fullband mode (HD+ is also used).[23]
See also
- QoS Class Identifier (QCI) – the mechanism used in VoLTE networks to allocate proper Quality of Service to bearer traffic
- Voice over NR
- Video over LTE
- Wideband audio
- Enhanced Voice Services
- List of LTE networks
References
- ISBN 978-1-119-95168-1.
- ^ "Voice and communication services in 4G and 5G networks". Ericsson.
- ^ Nick Russell (3 March 2013). "Official Document IR.92 – IMS Profile for Voice and SMS" (PDF). GSMA. Retrieved 14 September 2014.
- ^ "VoLTE and ViLTE: Global Market Update". GSA. 4 March 2024.
- ^ "VoLTE & ViLTE: Global Market Update - August 2019". GSA. 2024-06-13. Retrieved 2024-06-16.
- ^ "Wifi calling and VoLTE: Do you know the best calling standards?". digitec. 2019-05-09. Retrieved 2024-03-05.
- ^ "What is VoLTE?". www.4g.co.uk. Retrieved 2024-03-05.
- ^ "The Potential Perils of 2G and 3G Switch Offs". EENA. Retrieved 2024-03-05.
- ^ Sugarman, Saul (January 31, 2017). "SFMTA Bus & Train Predictions Restored, Mostly". Hoodline. Archived from the original on 2017-04-23.
{{cite web}}
: CS1 maint: unfit URL (link) - ^ "MetroPCS lights up Voice over LTE (VoLTE) services, starts selling LG Connect 4G". Engadget. Retrieved 2018-08-08.
- ^ "SingTel, Samsung and Ericsson unveil world's first full-featured Voice over LTE service". SingTel. 19 May 2014. Retrieved 4 August 2014.
- ^ "KT and China Mobile claim world first for cross-border VoLTE roaming". TeleGeography. 13 June 2014. Retrieved 14 September 2014.
- ^ "Verizon, AT&T partner to enable VoLTE interoperability". 3 November 2014. Retrieved 4 November 2014.
- ^ Segan, Sasha. "Verizon Is Heading Toward a Gigabit, CDMA-Free Future". PCMag. Retrieved 14 November 2017.
- ^ "Seatel Cambodia to invest $400m into 4G". telecomasia.net. 2015-02-11. Retrieved 2015-02-11.
- ^ "GT-Tell buyer SEATEL investing in 4G rollout". TeleGeography. 2015-02-10. Retrieved 2015-02-10.
- ^ "Seatel, ZTE to deploy FDD-LTE network in Cambodia". RCR WIRELESS. 2015-06-23. Retrieved 2015-06-26.
- ^ "中兴通讯携手东南亚电信共建LTE 4G网络". CCTIME. 2015-06-18. Retrieved 2015-06-20.
- ^ "100% 4G VoLTE". Seatel. 25 Jun 2015. Retrieved 25 Jun 2015.
- ^ "Verizon delaying shutdown of its 3G wireless network". CNN. 7 Jan 2021. Retrieved 18 May 2021.
- ^ "3G CDMA Network Shut off date set for December 31, 2022". Verizon Wireless News Center. 30 Mar 2021. Retrieved 18 May 2021.
- ^ "LTE delivers superior voice, too" (PDF). Ericsson. 2010. Archived from the original (PDF) on 24 September 2015. Retrieved 14 September 2014.
- ^ a b c d "EVS". Fraunhofer Institute for Integrated Circuits IIS. Retrieved 2020-05-10.
- ^ "HD Voice". Future Networks. Retrieved 2020-05-10.
- ^ "Fraunhofer IIS Presents the World's First Full-HD Voice Calls on Android Phones over LTE at Mobile World Congress 2017" (PDF). Fraunhofer IIS. 23 February 2012. Retrieved 23 June 2015.