Introduction to 3G Mobile Communications

The actual specification development within 3GPP is done in technical specification groups (TSGs). Originally there were four TSGs; the fifth group, GSM EDGE Radio Access Network (GERAN) was set up in mid-2000 to continue the specification work of advanced GSM features. 3GPP inherited this task from ETSI Special Mobile Group (SMG).
Each TSG is divided into several working groups (WGs). These are given well-defined tasks and responsibilities, as shown in Figure B.1. The working practices and methods that are used in 3GPP are defined in the 3GPP specification 3G TR 21.900.
3GPP specifications and reports have been divided into 15 series, which are numbered from 21 to 35.
21-series
Requirements specifications.
22-series
Specifications concerning services, service features, and platforms for services.
23-series
Technical realization series; contains specifications describing interworking over several interfaces.
24-series
Specifications of signaling protocols between MS/UE and the core network; that is, nonaccess stratum protocols.
25-series
UTRA aspects.
25.100-series
The radio performance of UTRAN.
25.200-series
UTRA physical layer 1.
25.300-series
UTRA radio interface architecture, L2 and L3 aspects.
25.400-series
The Iub, Iur, and Iu interfaces within UTRAN.
26-series
Codecs (speech, video, etc.)
27-series
The functions necessary to support data applications.
28-series
Reserved for future use.
29-series
The protocols within the core network.
30-series
3GPP program management.
31-series
The user identity module (UIM) and the interfaces between UIM and other entities.
32-series
Operation and maintenance aspects of the 3GPP mobile system network.
33-series
Security aspects.
34-series
Test...