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Comment: Added new WT numbers for WT-493: IMS for 5G-RG Architecture, and WT-494: IMS for 5G-Rg Residential Voice Requirements

Project Stream Information

Project Lead:  Martin Taylor 
Provide a profile of IMS behavior suitable for RGs attached to a 5G system, designed to maximize operational and procedural commonality with practices and the architecture of voice services in the mobile network.  The starting point would be a combination of GSMA NG.114 and operator input.

The intention is to provide support for the following classes of devices connected to a 5G-RG:

  • voice band data devices such as fax terminals and point-of-sale terminals.
  • POTS handset
  • business services (e.g. PBX), this may include supporting and interworking external SIP clients and supporting multiple services


The project will be performed in phases:

1) A study period whereby the aspects of GSMA NG.114 that are required by operators for PSTN simulation are identified as well as features not covered in NG.114, as well as what CODECs are required to be supported.  The study would include such considerations as operator requirements and regulatory obligations, voice quality, security etc.  An additional objective would be determine if existing feature sets can be reduced to eliminate support for obsolete features.  At the end of the study period a document plan will be established for the specification work.  This may be one or more TRs or one or more separate voice modules as a further amendment to TR-124 is created.

2) A specification period.

3) Extensions to the CWMP/USP data model.

Testing and interoperability could be future considerations

What will not be in scope (at least initially) will be: ISDN BRI and PRI support

Business Drivers and Impact:

Define a profile of 5G-RG behavior to support PSTN simulation in the context of voice in the 5G System

The primary motivation is the savings that can be achieved by convergence onto the mobile voice system, and voice quality improvements achievable by the use of contemporary CODECs. This is as opposed to the status quo whereby operators maintain two systems for voice with the attendant overhead.

Shifting wireline PSTN emulation to align with how voice is delivered in the 5G system would drive convergence and hence savings in a number of areas:

  • IMS authentication and procedures
  • subscriber management
  • service on-boarding
  • legal intercept
  • minimizing transcoding requirements
  • craftsperson training, troubleshooting, tooling
  • provide a definition to which all 5G-RG traffic entering IMS can be compliant to

For more information, please also refer to the New Project Initiation Form (NPIF) for the project.

Project Deliverables and Current Work in Progress

ItemTitle / DescriptionEditorsTimeline
WT-493IMS for 5G-RG Architecture

WT-494IMS for 5G-RG Residential Voice Requirements


RG related

WT-124 - 5G-RG Requirements

WT-181 - Data model support for 5G-RG

WWC in collaboration with BUS Work Area

Meeting / Conference Call Calendar
(Note: Contribution deadline is the preceding Monday COB )

Technical: THU 7AM PAC 2hs
1st hour: 5G PS, 2nd hour: IMS for 5G-RGPS

Marketing: THU 8AM PAC 1h

Agendas and Minutes 

For meeting & conference call agendas and minutes please refer to the PS wiki child pages.

IMS for 5G-RG PS Contribution Guidelines

We make use of collaborative tools, i.e. the BBF JIRA (CONTRIB project) and wiki


  • Study and draft material (e.g.) have child pages under the PS wiki home page where the content is hosted.  
    Wiki pages are updated based on group consensus.
    Editor's (appointed by the group) are responsible to incorporate changes into group's documents
    -unless agreed by the group, updates are not supposed to be done by non-editors.  [In case such an edit accidentally happened, editors may reset content to the previously agreed version.]
  • A snapshot of wiki pages/content can be easily extracted by everyone at any time, as word or pdf-document, using the wiki functions.
  • Before approval by the BBF membership, all developed content (wiki pages, SD, WT, etc) are BBF members-only.

Contributors are encouraged to use JIRA to make contributions:

  • JIRA CONTRIB Project - using the BBF contribution template

In addtion, contributions can be made:

  • by posting comments on the mailing list
  • by posting comments directly on the wiki pages using the “talk” function

Contribution handling/resolution:

We will preferably handle new contributions on the bi-weekly conference call series, but they can also be discussed via email (and via f2f meetings)

For conference calls, the contribution upload deadline is three business days prior to the call (i.e. Monday COB, for the current series).

Editors update the document baseline(s) according to agreements (documented in meeting minutes or on the mailing list), i.e. incorporate contributions. For additional information please refer to editor guidelines.