VoLTE Single Radio Voice Call Continuity (SRVCC)

What is Single Radio Voice Call Continuity (SRVCC)?


SRVCC is an LTE functionality that allows a VoIP/IMS call in the LTE packet domain to be moved to a legacy voice domain (GSM/UMTS or CDMA 1x).

Consider a case where a new LTE network operator wants to move voice services to VoIP over IMS in conjunction with the deployment of an LTE access network. In the absence of other options, this operator would need to provide ubiquitous LTE coverage on day 1 to have a competitive VoIP service. However SRVCC enabled LTE may not require complete LTE coverage. 

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VoLTE Training Course

VoLTE as the Technology of Choice for LTE Voice Transmission and SMS

 GSM Association IR.92 specifications highlight specific standards to deliver voice and SMS services over an LTE network with IMS (IP Multimedia Sub-systems).  WiFi as an “offload” is also an interesting concepts for many operators. VoLTE is essentially VoIP over 4G/LTE using IMS architecture.

In order for LTE UE to establish a voice call over IMS, the following steps are essential:

• UE RRC Connection Request to EPC & IMS
• PDN Connectivity Request 
• Protocol Configuration Options IE 
• P-CSCF address
• EPS Attach & P-CSCF Discovery
• UE initial IMS registration

KEY TECHNICAL REQUIREMENTS FOR VoLTE ARE:

• PCC rule authorization and QoS rule generation
• Multiple Bearers (Default, Dedicated)
• QoS Class Identifiers (QCIs)  
• Semi-Persistent Scheduling
• Transmission Time Interval (TTI) Bundling
• Discontinuous Reception (DRX)
• Robust Header Compression (RoHC)

COMMON RTP PAYLOAD TYPES FOR VOLTE ARE:

• Audio AMR 8000
• Audio AMR-WB 16000
• Text T140 1000
• Video H.263 90000
• Audio EVRCB 8000
• Audio EVRCWB
• Video H.263-2000 90000
• Video H.263-2000 90000
• Video H.264
• Video MP4V-ES 90000 

Evolution from GSM to LTE-Advanced and Voice over LTE (VoLTE)

From GSM to Voice over LTE (VoLTE)

Voice-over-LTE is a big deal for mobile operators worldwide today moving subscribers from their traditional 2G networks to their new 4G networks. Operators want to to get off of GSM and CDMA and on to LTE to increase their capacity tenfold or more for their networks.

Voice and messaging services for Long-Term Evolution (LTE) is happening.  Using IP Multimedia Subsystem (IMS) developed by 3GPP, end-to-end voice and SMS messaging along with Roaming and Interconnection is a reality now.

VoLTE is built upon underlying 3GPP principles including LTE and IMS. VoLTE has similar characteristics like Vonage. It is more than just Voice over IP (VoIP). The IP networks are mostly managed with MPLS or other layer 2/3 techniques.

Rather than connecting an legacy circuit switched call, VoLTE calls are transmitted over LTE EPC and IMS networks using SIP as the signaling protocol.

VoLTE can use "HD Voice" or Rich Communication Services (RCS) will merge picture and video messaging.

RCS (Rich Communication Services) will deliver high quality voice and SMS by providing them with instant messaging or chat, live video and file sharing across any mobile device, on any network.  

VoLTE Training Course - Bootcamp Style

 Voice over LTE Training Course (VoLTE Training Bootcamp):  The next innovation in the wireless industry

TONEX Voice over LTE training 3-day course is a unique crash course, bootcamp style that covers all aspects of  VoLTE, Evolved Packet Core (EPC), IP Multimedia Subsystem (IMS) for delivery of various services such as voice, SMS, video and other services such as IM and Presence over LTE/EPC/IMS.

Topics incuded:  VoLTE basic concepts, architecture, network nodes, protocols, interfaces, session handling, media and control, frameworks, profiles, operational scenarios, QoS, security, charging and roaming.