Voice over LTE: Difference between revisions

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[[File:VoLTE Settings - Android 12 - Xperia 1 II.png|thumb|654x654px|VoLTE Settings - Android 12 - Xperia 1 II]]

With 2G or 3G still being in service consumers don’t experience any loss in device functionality by switching to a competing provider. However, with the shutdown of 2G/3G services consumers may no longer be able to make or receive standard phone calls on their existing 4G device with their preferred mobile carrier. This also impacts Emergency Calls and Roaming Calls, not all devices with VoLTE Calling support can place Emergency Calls or Roaming Calls over 4G.

Currently phone carriers are able to use this telco Specific VoLTE firmware requirement as a stealth way of network locking their devices and preventing customers from switching to competitors or from using ‘BYO’ devices.<ref>[https://independentaustralia.net/politics/politics-display/australias-3g-shutdown-why-your-4g5g-phone-is-now-blocked,19159 "Australia’s 3G shutdown: Why your 4G/5G phone is now blocked - Independent Australia"] - 12 November 2024</ref> Handset makers & network operators also engage in behavior that restricts the use of devices on different networks and behavior that otherwise undermines competition.<ref>[https://www.aph.gov.au/Parliamentary_Business/Hansard/Hansard_Display?bid=committees/commsen/28167/&sid=0000 "3G Shutdown Inquiry - Committee Hansard - 23 July 2024 Parliament of Australia"] - aph.gov.au</ref>

Unlike calling with 2G and 3G there is no single configuration for VoLTE that all devices and networks universally support. Some networks support the GSMA IR.92 'Open Market Device' Configuration.<ref name=":1">Parker, James (31 August 2024). "[https://medium.com/@jamesdwho/how-to-check-for-working-volte-calling-on-android-8c343362ecfe How to Check for Working 4G VoLTE Calling on Android Handsets | The Problems with VoLTE Interoperability & Standardisation]". ''Medium.com''. Retrieved 2 September 2024.</ref> This configuration is intended to be a generic/global VoLTE configuration that can be used by Open Market (non-carrier) devices.<ref>Doug Makishima, GSMA (1 December 2015). [https://www.itu.int/en/ITU-T/Workshops-and-Seminars/conformity-interoperability/20150112/Documents/Abstracts%20and%20Presentations/S3P5_Doug_Makishima.pdf "ITU Workshop on "Voice and Video over LTE""] (PDF). ''ITU''.</ref> 4G/LTE Devices that lack native VoLTE calling support are reliant on 2G/3G Networks to make or receive calls (via Circuit Switched Fallback - CSFB) and without either 2G or 3G Networks those devices do not have call service.

With some Qualcomm based Android devices it is possible to modify the device firmware with special software and manually load a compatible carrier modem configuration.<ref name=":1">Parker, James (31 August 2024). "[https://medium.com/@jamesdwho/how-to-check-for-working-volte-calling-on-android-8c343362ecfe How to Check for Working 4G VoLTE Calling on Android Handsets | The Problems with VoLTE Interoperability & Standardisation]". ''Medium.com''. Retrieved 2 September 2024.</ref> By modifying the firmware customers can use VoLTE calling, however the carrier may not recognise those devices as supported despite working correctly.

[[File:Android IMS Status for Voice over LTE.jpg|thumb|280x280px|Android IMS Status for Voice over LTE]]

Android users are able to confirm if VoLTE is working by checking for the Device 'IMS Status' within a hidden Radio Info Debug menu.<ref name=":1">Parker, James (31 August 2024). "[https://medium.com/@jamesdwho/how-to-check-for-working-volte-calling-on-android-8c343362ecfe How to Check for Working 4G VoLTE Calling on Android Handsets | The Problems with VoLTE Interoperability & Standardisation]". ''Medium.com''. Retrieved 2 September 2024.</ref><ref>[https://www.androidpolice.com/best-secret-codes-for-android/ "The best secret short codes for your Android phone"]. ''Android Police''. 27 June 2024.</ref>

''Note: UT Interface is not required for VoLTE Calling, UT Interface is only required to change supplementary service settings (i.e. call forwarding) on a 4G/LTE only network. Devices without an "Available" UT Interface are reliant on 2G/3G networks to change call forwarding/busy settings.''  

[[File:VoLTE Emergency Calling Android 8.0.png|thumb|391x391px|VoLTE Emergency Calling Android]]

Not all devices that have been sold as 'VoLTE capable' support making calls to Emergency Numbers over 4G/LTE with VoLTE.<ref name=":2" /> Some carriers and manufacturers have disabled the ability for phones to call Emergency Services with VoLTE and the devices are reliant on 2G or 3G Networks to make calls to Emergency Services.<ref>[https://eena.org/knowledge-hub/press-releases/the-potential-perils-of-2g-and-3g-switch-offs/ "The Potential Perils of 2G and 3G Switch Offs"]. ''EENA''. 12 September 2022. Retrieved 7 August 2024.</ref>

These issues aren't well known to the general public. However, in his EENA presentation, he said these issues are '''''“Common Knowledge”''''' in the industry and that '''''“..there is nobody who feels responsible to fix this”.'''^(16:45)'' <ref name="EENA2022" />

A device can have working VoLTE Calling (IMS Registration) on a network but may not be able to successfully make calls to emergency numbers over 4G. For Android devices there are methods to test a device for 4G Emergency Calling support; however, such testing can require third-party software and tools to perform. Simply dialing an Emergency Number on a 4G device is '''not''' sufficient to test if a device can make VoLTE Emergency Calls.<ref name=":0" />

Telstra was originally set to switch off their 3G Network on 30 June 2024. Telstra extended their switch off to 31 August in early May 2024.<ref>[https://www.abc.net.au/news/2024-05-06/telstra-to-extend-3g-network-shutdown/103808110 "Telstra to Extend 3G Shutdown' - Jane Norman – 6 May 2024"]. ''ABC News''. 6 May 2024. Retrieved 7 August 2024.</ref> On 14 August 2024, Telstra and Optus further extended the 3G switch off date to 28 October 2024.<ref>[https://www.optus.com.au/about/media-centre/media-releases/2024/08/optus-and-telstra-announce-extension-to-3g-network-closures "Telstra and Optus announce extension to 3G network closures"]. ''optus.com.au''. 14 August 2024.</ref> Vodafone completed their 3G switch off in early January 2024.<ref>[https://www.vodafone.com.au/support/network/3g-closure "We have switched off our 3G network"]. ''Vodafone Australia''. Retrieved 2024-09-02.</ref>

Below are two tables of Qualcomm Modem configurations that were tested on Australian 4G/LTE Networks ([[Telstra]], Optus and Vodafone AU/TPG Telecom) in addition to 000 ‘Triple Zero’ (112) 4G Emergency Calls. The modem configurations/profiles specify the exact settings a device modem needs to use in order to communicate with a particular carrier network. This can include information for VoLTE Calling, WiFi Calling, Video Calling and band aggregation, amongst other factors.

It’s also worth noting that devices running the Singtel Modem Configuration <u>do not</u> work on the Optus network despite Singtel being the parent company, 4G Emergency calls also <u>do not</u> work with the tested Singtel Modem Configurations. As shown below, devices running a generic GSMA IR.92 ‘Open Market Device’ VoLTE configuration can work on competing Australian networks Optus & Vodafone/TPG including for Emergency Calls on all Australian networks.

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[[Category:Protocols]]