
Circuit switched networks physically connect two endpoints using a communication channel through the network. This utilises a fixed bandwidth for the session whilst the two endpoints remain connected. Packet switched networks offer the ability to split the communication channel into small packets to be sent across the network using multiple routes offering redundancy and increased performance. This utilises dynamic bandwidth management which can be optimised for each connected party and allows for many more services and connections to be active at the same time using the same bandwidth.
In the cellular network GSM (2G) and UMTS (3G) use circuit switching for voice, circuit switched dialup (CSD) and short messaging service (SMS) traffic and use packet switching for GPRS data traffic. In LTE (4G) the entire network uses packet switching and has no capability for circuit switched network support. As a result, the voice and SMS services must be moved over to a packet switched network when using the LTE (4G) network. In addition to this, CSD is no longer supported and GPRS data must be used instead.
Please see Circuit Switched Dialup (CSD) Migration to LTE Application Note' here.
Voice Overview Many applications in use today utilise voice as part of the service offering. This may be to connect two parties together to communicate such as in an elevator emergency failure system, to implement an automated payment service using a dial keypad or report a fault with a system using normal spoken language. Whatever the reason for using the voice service in a cellular system, there are some differences with the LTE network which are described in more detail below.
On legacy devices supporting GSM (2G) and UMTS (3G) services, the voice and SMS components of the system use circuit switching as the transmission channel. For GSM the whole system was built on an analogue infrastructure and digital data was added to the system later with the advance of GPRS packet data. The UMTS system is based on the GSM standard and therefore also supports both digital and analogue components. The UMTS framework allows much higher data rates over GSM but is still based on a similar infrastructure.
LTE on the other hand is entirely digital and has no analogue components at all. Therefore, new methods are used to take advantage of the new features offered by the LTE network as analogue voice calling is no longer possible and the packet switched network must be adopted.
VoLTE (Voice over LTE) Overview The LTE network supports voice and many other additional services in the same way as GSM and UMTS, however, as there is no analogue component the voice must be encoded and sent digitally across the network using packets. The 3GPP body have specified the voice service on LTE which is highly optimised and takes advantage of the additional bandwidth and low latency of the LTE network. This service is called Voice over LTE (VoLTE) and uses the digital packet switched network in a much more efficient way than traditional services. This means that VoLTE can support up to 3 times more voice capacity than previous UMTS networks and up to 6 times more capacity than older GSM networks.
The VoLTE service is provided on LTE over the IP Multimedia System (IMS) network service which is a standardized framework for delivering multimedia services over TCP/IP. It has been developed to allow all content rich media from wireless and wireline applications and allows for advanced services to be provided over the existing infrastructure without the need for individual control functions for each service.
The network provider must support IMS to be able to offer VoLTE as a service to its customers. The IMS framework must be integrated within the network's core architecture and is fundamental to the operation of the network.
Network Usage with Circuit Switch Fall Back (CSFB) With existing GSM (2G) and UMTS (3G) networks, the core functions are built into the application and can be supported with any hardware platform that supports voice and any SIM card that supports voice. This allows for a very simple implementation and calls can be established without any special configuration to the end equipment.
With newer modems that support LTE (4G) in addition to GSM (2G) and UMTS (3G) the firmware in the modem performs a subtle trick to continue having seamless voice support. When connected to the network for transmitting digital packet data, the unit connects to and uses the LTE network. When attempting to dial a voice number the unit automatically switches to UMTS (3G) or GSM (2G) to establish the call. Once the call is finished it reverts to the LTE network. This technology is called circuit switch fall back and is a short-term solution to allow all network providers to offer voice services on the LTE network whilst they implement their own full IMS solution.
This process is fine whilst there are UMTS (3G) and GSM (2G) networks available to use but the analogue networks are being gradually sunset to be replaced entirely with the LTE network.
With the LTE (4G) network it is necessary to configure the device to allow calls to be made using the LTE only network over the IMS service.
SMS Overview The short messaging service (SMS) can be used to send and receive small text messages which can be used in a variety of ways for applications that use the cellular network. The messaging service can be used to configure settings in remote equipment as well as reporting on the current configuration. In addition, the messaging service can inform users directly of a triggered alarm state or indicate when a certain criterion has been met. As with voice, the existing GSM (2G) and UMTS (3G) core functions are built into the system and can be supported with any hardware platform that supports the SMS messaging service and any SIM card that has SMS functio
Most recent headlines
05/01/2027
Worlds first 802.15.4ab-UWB chip verified by Calterah and Rohde & Schwarz to be ...
04/08/2026
Dalet, a leading technology and service provider for media-rich organizations, t...
04/07/2026
April 7 2026, 19:00 (PDT) Detective Conan: Fallen Angel of the Highway Opens in...
09/06/2026
Kiswe announces an expanded long-term partnership with ONE Championship (ONE), t...
09/06/2026
SiriusXM will broadcast FOX Sports' English-language commentary for all 104 FIFA World Cup 2026 matches from June 11 through July 19, available to subscribe...
09/06/2026
EVS has announced it is changing its corporate name from EVS Broadcast Equipment to EVS, reflecting the company's expanded portfolio beyond broadcast equipm...
09/06/2026
Fox Corporation and the NFL have announced a multi-year agreement to bring NFL c...
09/06/2026
FOX Sports and ReachTV, an airport media network, have announced an agreement to...
09/06/2026
Cosm Atlanta, a 70,000-square-foot, three-level immersive entertainment venue located within Centennial Yards adjacent to State Farm Arena and Mercedes-Benz Sta...
09/06/2026
NESN captured five awards at the 2026 Boston/New England Emmy Awards, including four program honors and one individual award.
These awards reflect the passion...
09/06/2026
Ateme has announced that its support for Apple Immersive Video workflows was referenced by Apple during its 2026 Worldwide Developers Conference (WWDC26).
Atem...
09/06/2026
Bitmovin has announced that Axel Springer SE has deployed Player Web X, Bitmovin's web video player, to power audio readouts of news articles and an audio-o...
09/06/2026
Grass Valley and Lawo have announced a technology collaboration to validate orch...
09/06/2026
LiveU has announced a deployment with the Oceania Football Confederation (OFC) t...
09/06/2026
Globecast has announced the launch of its Content Exchange platform, powered by ...
09/06/2026
NBC Sports will present live coverage of Overtime's OT7 football league Championship Weekend from Sullivan Field at Loyola Marymount University in Los Angel...
09/06/2026
We're in three different locations, three different production teams. Coveri...
09/06/2026
The intro video for Men's Basketball won Outstanding In-Venue Video in the C...
09/06/2026
Today is match day minus two for FIFA and HBS. On Thursday, there will be two ma...
09/06/2026
Since their debut, the clock-and-score graphic has drawn the affinity and ire of...
09/06/2026
Last month, Spotify hosted PURE FLOWERS LIVE, a special event celebrating the re...
09/06/2026
Last month, RADAR U.K. artist Skye Newman took the stage in East London for a sp...
09/06/2026
Company to cease operating on 30 June 2026
Australian loudspeaker and amplifier manufacturer Wayne Jones Audio have announced that after much consideration,...
09/06/2026
Increases low-end weight and character
The latest plug-in release from Sheffield-based fedDSP aims to offer an all-in-one solution for users in search of mo...
09/06/2026
Introduces AI Studio Assistant, Moises Studio integration & more
Fender Studio have just announced the launch a significant update that brings an array of n...
09/06/2026
The National Film and Video Foundation (NFVF) is a statutory body mandated to spearhead the equitable growth and development of the South African film and video...
09/06/2026
The BBC has found its Hercule Poirot.
After Deadline revealed last month that t...
09/06/2026
Media buyers and sellers can now compare YouTube reach from computer, mobile, an...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
A project aimed at modernizing scheduling operations across Mediaset's channel portfolio
Mediagenix, a global leader in smart content solutions to profitab...
09/06/2026
tvONE, an ACT Entertainment brand, debuts its most powerful video processor ever built: the 4RU CALICO PRO (C7-PRO-4200), at InfoComm 2026 (Booth N6813). Engine...
09/06/2026
Composer and Conductor Eric Whitacre to Receive Honorary Doctorate at Berklee Va...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Technology collaboration to validate AMPP and Lawo HOME orchestration integration, showcasing Dynamic Media Facility principles in practice.
Grass Valley and ...
09/06/2026
Bitmovin, a leading provider of video streaming solutions, today announced that Axel Springer SE, international media and technology company, has deployed Playe...
09/06/2026
LiveU, the global leader in live IP-video solutions, today announced a landmark deployment with the Oceania Football Confederation (OFC) that has brought Video ...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Share
Copy link
Facebook
X
Linkedin
Bluesky
Email...
09/06/2026
Two Alumni Win Tony Awards Mike Morris and Cedric Leiba Jr. won awards for Best Orchestrations and Best Play, respectively.
June 8, 2026
By
Tori Donahue
...
09/06/2026
X-Rite Pantone Launches Offset360 to Modernize Color Control Across Existing Pre...
09/06/2026
09 Jun 2026
VEON Appoints Serkan Ozturk as Chief of Staff & Strategy Officer Dubai and New York, June 9, 2026 - VEON Ltd. (NASDAQ: VEON), a global digital oper...
09/06/2026
Tuesday 9 June 2026
Katie Price: Nothing to Hide, a candid and unfiltered accou...
09/06/2026
Back to All News
Netflix Unveils First Images And Poster For Wrath, A New Brazi...
09/06/2026
Enni Continues to Rely on Arvato Systems - And Will Be Using AEP.EnerS4 Billing Solution
Arvato Systems to implement transformation project for SAP S/4HANA Ut...