Core Network (CN) - Technical Specification Group (TSG CN)
One of the four original 3GPP TSGs, TSG CN was closed in March 2005, most of its work being transferred to the new TSG CT working groups.
Core Network and Terminals (CT) WG5 – OSA
CT WG5 was responsible for Development and maintenance of specifications and associated test specifications for Open Services Access (OSA). On closure of the working group, maintanence of these specifications was transferred to TSG CT (plenary group) and future development was transferred to the Open Mobile Alliance.
GERAN- Technical Specification Group (TSG GERAN)
TSG GERAN was responsible for the specification of the Radio Access part of GSM/EDGE. On its closure, May 2016, the work was transferred to RAN6 (Closed in 2020, see below), with conformance test specifications going to WG RAN5.
RAN WG6 - GERAN and UTRAN radio and protocol
WG RAN6 was closed, following RAN#88-e in June 2020. The GERAN work is transferred to TSG RAN.
Terminals - Technical Specification Group (TSG T)
One of the four original 3GPP TSGs, TSG T was closed in March 2005, its work being transferred to TSGs RAN and CT. Terminal testing work went to RAN5.