A Global

The Mobile


Working Group CT1 is responsible for the 3GPP specifications that define the User Equipment - Core network L3 radio protocols and Core network side of the Iu reference point. Specifically it has a responsibility for:

  • User Equipment - Core network layer 3 radio protocols (Call Control, Session Management, Mobility Management, SMS);
  • Management of work items placed under its responsibility.


Terms of reference

The latest terms of reference were approved at CT#58 in document CP-120902.zip.

The scope of CT1 is the following:

  • Mobility Management, Call Control, Session Management, and Location services L3 signalling between the user equipment and the core network;
  • Mobile Radio L3 stage 3 (3GPP TSs 24.008 and 24.301);
  • Application and extension of SIP, SDP, XCAP as call control and service enabling protocols for the IMS for all applicable access technologies (3GPP TS 24.229 and others);
  • Interaction of SIP related procedure with GPRS / EPS procedures;
  • Integration of non-3GPP access protocols to the 3GPP CN (3GPP TSs 24.302 and 24.301);
  • Interworking with fixed-broadband access;
  • Access Transfer technologies (DRVCC/SRVCC);
  • Circuit Switched Fallback (CSFB);
  • Location mobility between 3GPP WLAN and 3GPP GPRS/SAE (3GPP TS 24.327);
  • Voice Broadcast (Group) Service;
  • EPC and 3G related Machine-to-Machine communication aspects;
  • Cell Broadcast System and Public Warning Systems (3GPP TS 23.041);
  • Mobile station remote configuration;
  • Integration of WLAN in 3GPP mobile environment at the radio interface;
  • MM part of the MS idle mode functionality;
  • CN side of the Iu reference point;
  • SGSN-VLR (Gs) interface;
  • MME-VLR (SGs) interface;
  • Mobile Radio L3 requirements (3GPP TS 24.007);
  • AT command set for the UE;
  • Point-to-point Short Message Service (SMS) stage 2 and stage 3 (3GPP TSs 23.038, 23.039, 23.040, 23.042, 24.011 and 24.341);
  • Ua, Ub, Upa interface for Generic Authentication Architecture (GAA);
  • H(e)NB control and interworking;
  • Multimedia telephony, supplementary services and advanced services for IMS – stage 2 and stage 3;
  • Application Server architecture for the IMS – stage 2 (3GPP TS 23.218);
  • Interworking with other networks (e.g. handover and roaming) together with CT3 and CT4;
  • Signalling between the Core network nodes placed under its responsibility together with CT4;
  • Management Objects associated with the protocols under CT1 responsibilites.

In this task CT1 has also the maintenance responsibility of the older versions of the specifications placed under its responsibility.

Useful links and information

About CT WG1 List of elected officials
Documents Meeting documents see also CN1
  Work items
Meetings Next meeting information & previous meeting reports and documents see also CN1
  Liaisons Statements
  Full CT WG1 meeting calendar
General info [3GPP IETF Dependencies - from TSG#52 Jun 2011 onwards the 3GPP-IETF Dependencies are included in the 3GPP Work Plan
  Email exploder lists
  List of URNs maintained by CT WG1
  Link to PCPS specifications from OMA
CT Working groups 
TSG CT Plenary  
[No WG2] See Old Terminals Group 2
TSG CT WG3 Interworking with external networks
TSG CT WG5 OSA (Now transferred to OMA)
TSG CT WG6 Smart Card Application Aspects


CT1 delegate survival guide

or ... all you wanted to know about participating in CT1 meetings but were afraid to ask

Connecting to the local meeting server MCC installs a wireless LAN for the duration of the meeting. Connecting to this network provides the delegates with Internet and access to a local server used for exchanging files during the meeting. Wireless LAN SSID: 3GPP key: 3GPPM You can find more information on connecting to the WLAN here. Local Web server URL: . The web page (...)


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