Editing Voice over IP (section)

==Overview==
The steps and principles involved in originating VoIP telephone calls are similar to traditional digital [[telephony]] and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a [[circuit-switched network]], the digital information is packetized and transmission occurs as IP packets over a [[packet-switched network]]. They transport media streams using special media delivery protocols that encode audio and video with [[audio codec]]s and [[video codec]]s. Various codecs exist that optimize the media stream based on application requirements and network bandwidth; some implementations rely on [[narrowband]] and [[Speech coding|compressed speech]], while others support [[high-fidelity]] stereo codecs.

The most widely used [[speech coding]] standards in VoIP are based on the [[linear predictive coding]] (LPC) and [[modified discrete cosine transform]] (MDCT) compression methods. Popular codecs include the MDCT-based [[AAC-LD]] (used in [[FaceTime]]), the LPC/MDCT-based [[Opus (audio format)|Opus]] (used in [[WhatsApp]]), the LPC-based [[SILK]] (used in [[Skype]]), [[μ-law]], [[A-law]] versions of [[G.711]], [[G.722]], an [[Open-source license|open source]] voice codec known as [[iLBC]], and a codec that uses only 8&nbsp;kbit/s each way called [[G.729]].

Early providers of voice-over-IP services used business models and offered technical solutions that mirrored the architecture of the legacy telephone network. Second-generation providers, such as [[Skype]], built closed networks for private user bases, offering the benefit of free calls and convenience while potentially charging for access to other communication networks, such as the PSTN. This limited the freedom of users to mix-and-match third-party hardware and software. Third-generation providers, such as [[Google Talk]], adopted the concept of [[federated VoIP]].<ref>{{cite web|url=http://googletalk.blogspot.com/2006/01/xmpp-federation.html|title=XMPP Federation|publisher=Google Talkabout|year=2006|access-date=May 11, 2012}}</ref> These solutions typically allow dynamic interconnection between users in any two domains of the Internet, when a user wishes to place a call.

In addition to [[VoIP phone]]s, VoIP is also available on many personal computers and other Internet access devices. Calls and SMS text messages may be sent via [[Wi-Fi]] or the carrier's [[mobile data]] network.<ref name=EBSCOhost>{{cite journal|last=Booth|first=C|title=Chapter 2: IP Phones, Software VoIP, and Integrated and Mobile VoIP|journal=Library Technology Reports|year=2010|volume=46|issue=5|pages=11–19}}</ref> VoIP provides a framework for consolidation of all modern communications technologies using a single [[unified communications]] system.

=== Integration of VoIP in mobile networks ===
VoIP technology has been adapted for use in [[Cellular network|mobile networks]], leading to the development of advanced systems designed to support voice communication over modern data infrastructures. Among these are Voice over LTE ([[VoLTE]]) and Voice over 5G ([[Vo5G]]), which enable voice communication over IP-based mobile infrastructures. In contrast to traditional VoIP services, which often function independently of global telephone numbering systems, VoLTE and Vo5G are directly connected to [[mobile operator]]s' infrastructures, providing seamless connectivity to the international telephone network.<ref>{{Cite web |last=Wright |first=Arol |date=2023-10-12 |title=What Is Vo5G (VoNR) and How Does It Compare to VoLTE? |url=https://www.makeuseof.com/what-is-vo5g-vonr/ |access-date=2024-11-30 |website=MUO |language=en}}</ref><ref>{{Cite web |title=Communication services (VoLTE/VoNR) |url=https://www.3gpp.org/technologies/volte-vonr |access-date=2024-11-30 |website=www.3gpp.org}}</ref>

VoLTE, introduced as part of [[4G]] [[LTE (telecommunication)|LTE]] networks, enables voice communication over an IP-based infrastructure initially developed for data transmission. It offers features such as high-definition voice ([[HD Voice]]) and faster call setup times compared to [[Circuit-switched network|circuit-switched networks]].<ref>{{Cite web |title=What is Voice Over LTE (VoLTE)? Definition from WhatIs.com |url=https://www.techtarget.com/searchnetworking/definition/voice-over-LTE-VoLTE |access-date=2024-11-30 |website=Search Networking |language=en}}</ref>

Vo5G, the [[5G]] equivalent of VoLTE, utilizes the increased speed, reduced latency, and greater capacity of 5G networks to further enhance these capabilities.<ref>{{Cite web |title=What Is 5G VoNR {{!}} Unveiling the Future of Wireless Communication |url=https://www.voicenter.com/blog/5g-VoNR |access-date=2024-11-30 |website=www.voicenter.com |language=en}}</ref> Both VoLTE and Vo5G maintain compatibility with traditional [[public switched telephone network]]s (PSTNs), allowing users to make and receive calls to and from any [[telephone number]] worldwide.

These technologies differ from standalone VoIP services by being fully integrated with mobile network operators. This integration ensures additional features such as [[emergency call]] support and [[quality-of-service]] guarantees, making them a central part of modern mobile telecommunication systems.