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iPhone with active VoLTE Call

Voice over Long-Term Evolution (VoLTE) is a standard for high-speed wireless communication for mobile phones and data terminals — including IoT devices and wearables. It is based on the IP Multimedia Subsystem (IMS) network, with specific profiles for control and media planes of voice service on LTE defined by GSMA in PRD IR.92.^[1] This approach results in the voice service (control and media planes) being delivered as data flows within the LTE data bearer. This means that there is no dependency on (or ultimately, requirement for) the legacy circuit-switched voice network to be maintained. VoLTE has up to three times more voice and data capacity than 3G UMTS and up to six times more than 2G GSM. Furthermore, it frees up bandwidth because VoLTE’s packets headers are smaller than those of unoptimized VoIP/LTE.^[2]

History

In August 2012, MetroPCS launched the world's first commercial VoLTE services in Dallas, Texas. along with the first VoLTE phone, the LG Connect 4G.^[3]

In May 2014, Singtel introduced the world's first commercial "full-featured" VoLTE service in Singapore, only in combination with Galaxy Note 3, it was subsequently expanded.^[4]

In June 2014, KT showcased the world’s first cross-border roaming services based on Voice over LTE. The South Korean operator partnered with China Mobile to develop VoLTE roaming services.^[5]

In October 2014, operators based on IMS local breakout architecture with home routing systems.^[6]

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.^[7] This was stated to have been completed in November 2017. ^[8]

On 11 July 2015, SEATEL Cambodia announced the world's first commercial 100% VoLTE service without 2G/3G in Cambodia.^{[9][10][11][12][13]}

On 14 September 2015, Orange Romania has launched the VoLTE service for Samsung users in Romania.
^[14]

On 16 September 2015, Telstra announced that it had started enabling VoLTE across its network, including calling to National Broadband Network and business and enterprise services with HD handsets.^[15]

On 30 November 2015, Telenor Denmark launched VoLTE for all Samsung Galaxy S6 phones, which has since been followed by additional Samsung and Apple models.

In 2016, Vodafone Netherlands launched VoLTE support, along with Wi-Fi Calling.^[16]

On 30 June 2016, YTL's YES launches 4G LTE service to become Malaysia's FIRST VoLTE service provider.

In June 2016 Movistar Peru launched commercial VoLTE service in Peru, starting in Lima and Callao for Samsung Galaxy S6, S6 Edge and LG G4 phones. Service will be enabled progressively in other departments and handsets. Movistar Peru is the first operator in the country offering this service.

In July 2016, Etisalat became the first operator to launch VoLTE in UAE.

In July 2016, PT Smartfren Telecom launches VoLTE services working in partnership with Mitel, and become Indonesia's first VoLTE service provider.^[17]

On 1 September 2016, Dialog Axiata launched commercial VoLTE service in Sri Lanka.^[18]

On 5 September 2016, India's first 4G-only network Jio launched their commercial VoLTE service without 2G/3G based services.^[19]

In October 2016, Orange Polska launched commercial VoLTE service in Poland.

In November 2016, T-Mobile (Poland) launched commercial VoLTE service in Poland.

On 7 December 2016, Telenor Denmark launched VoLTE for all phones with VoLTE support.

On 8 March 2017, Cosmote is the first operator that launched VoLTE (and VoWiFi) service in Greece.

On 24 April 2017, TIM launched VoLTE for all phones with VoLTE support in Italy.

In June 2017, Pakistan's Largest telecom operator Jazz has tested VoLTE over its network. Jazz plans to commercially launch it in July 2017.

In June 2017, Bahrain's Largest telecom operator Batelco has semi-launched the service to iOS users.

In July 2017, Digi.Mobil (RCS & RDS) will be the second carrier that launches commercial VoLTE services in Romania.

In July 2017, TIM Brasil was the first carrier to sell VoLTE on Brazil.^[20]

In August 2017, Proximus was the first to activate VoLTE in Belgium. Customers were notified by SMS that the service was available.

In September 2017, Swazi Mobile was the first to activate VoLTE in Swaziland.

After this Bharti Airtel also launched the commercial VoLTE service in India.

In October 2017, Nova was the first to activate VoLTE in Iceland.

In November 2017, Telia Company was the first to activate VoLTE in Lithuania.

In November 2017 Entel Peru enabled VoLTE service in Peru, starting in Lima and Callao for Apple iPhone SE, Apple iPhone 6, Apple iPhone 6 Plus, Apple iPhone 6S, Apple iPhone 6S Plus, Apple iPhone 7, Apple iPhone 7 Plus, Apple iPhone 8, Apple iPhone 8 Plus, Apple iPhone X, Huawei Mate 9, Huawei Mate 10 Lite, Huawei P9, LG G4, Motorola MOTO C 4G, Motorola MOTO E4 Plus, Motorola MOTO G5S Plus, Samsung Galaxy J7, Samsung Galaxy S8, Samsung Galaxy S8+, Sony XPERIA L1 and Sony XPERIA XA1 Ultra phones.

In December 2017, Jamii Telecom Limited (JTL), offering broadband data services under the 'Faiba' brand, [1] was the first to activate VoLTE in Kenya.

In February 2018, Vodafone India's VoLTE, went live in the Delhi NCR circle, Gujarat and Mumbai^[21]

In March 2018, SS7ware, the company behind Yate, launched VoLTE Lab, intended for use as a VoLTE test bed and learning environment. ^[22]

In May 2018, Play launched commercial VoLTE service in Poland for supported iOS devices.

In June 2018, Orange and Telenet announced that VoLTE will be launched in Belgium.

In January 2019, Mobitel launched VoLTE in Sri Lanka.

In February 2019 WOM announced that VoLTE along with WiFi Calling will be launched in Chile. Currently working on select android devices (Samsung s8 and above, in addition to other Huawei models)

Deployment

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.^[23]

A list of commercial VoLTE deployments around the world can be found in the main article above.

Devices

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 as HD Voice. This codec is mandated in 3GPP networks that support 16 kHz sampling.^[104]
Volte
Fraunhofer IIS has proposed and demonstrated "Full-HD Voice", an implementation of the AAC-ELD (Advanced Audio Coding – Enhanced Low Delay) codec for LTE handsets. Where previous cell phone voice codecs only supported frequencies up to 3.5 kHz and upcoming wideband audio services branded as HD Voice up to 7 kHz, Full-HD Voice supports the entire bandwidth range from 20 Hz to 20 kHz. For end-to-end Full-HD Voice calls to succeed however, both the caller and recipient's handsets as well as networks have to support the feature.^[105]

See also

• LTE


• 
  IP Multimedia Subsystem (IMS)


• Wideband audio


• Video over LTE


• 
  QoS Class Identifier (QCI) – the mechanism used in VoLTE networks to allocate proper Quality of Service to bearer traffic

References