ETSI - TS 144 018
Digital cellular telecommunications system (Phase 2+) (GSM); Mobile radio interface layer 3 specification; GSM/EDGE Radio Resource Control (RRC) protocol
|Publication Date:||1 September 2020|
The present document specifies the procedures used at the radio interface (Reference Point Um, see 3GPP TS 24.002) for Radio Resource (RR) management.
Notation "Reserved sub-clause number" is used to indicate which sub-clauses of the specification were moved from this part of the standard to the other part when this standard was split between RAN and CN parts.
When the notations for "further study" or "FS" or "FFS" are present in this specification they mean that the indicated text is not a normative portion of this standard.
These procedures are defined in terms of messages exchanged over the control channels of the radio interface. The control channels are described in 3GPP TS 44.003.
The structured functions and procedures of this protocol and the relationship with other layers and entities are described in general terms in 3GPP TS 24.007.
Scope of the Technical Specification
The procedures currently described in the present document are for radio resource management for circuit-switched and GPRS services.
3GPP TS 24.010 contains functional procedures for support of supplementary services.
3GPP TS 24.011 contains functional procedures for support of point-to-point short message services.
3GPP TS 44.012 contains functional description of short message - cell broadcast.
3GPP TS 44.060 contains procedures for radio link control and medium access control (RLC/MAC) of packet data physical channels.
3GPP TS 44.071 contains functional descriptions and procedures for support of location services.
3GPP TS 24.008 contains the procedures for CN protocols.
NOTE: "layer 3" includes the functions and protocols described in this Technical Specification. The terms "data link layer" and "layer 2" are used interchangeably to refer to the layer immediately below layer 3.
Application to the interface structures
The layer 3 procedures apply to the interface structures defined in 3GPP TS 44.003. They use the functions and services provided by layer 2 defined in 3GPP TS 44.005 and 3GPP TS 44.006. 3GPP TS 24.007 gives the general description of layer 3 including procedures, messages format and error handling.
Structure of layer 3 procedures
A building block method is used to describe the layer 3 procedures.
The basic building blocks are "elementary procedures" provided by the protocol control entities of the three sublayers, i.e. radio resource management, mobility management and connection management sublayer.
Complete layer 3 transactions consist of specific sequences of elementary procedures. The term "structured procedure" is used for these sequences.
Test procedures of the GSM radio interface signalling are described in 3GPP TS 51.010 and 3GPP TS 51.02x series.
Use of logical channels
The logical control channels are defined in 3GPP TS 45.002. In the following those control channels are considered which carry signalling information or specific types of user packet information:
i) Broadcast Control CHannel (BCCH): downlink only, used to broadcast Cell specific information;
ii) Synchronization CHannel (SCH): downlink only, used to broadcast synchronization and BSS identification information;
iii) Paging CHannel (PCH): downlink only, used to send page requests to Mobile Stations (MSs);
iv) Random Access CHannel (RACH): uplink only, used to request a Dedicated Control CHannel;
v) Access Grant CHannel (AGCH): downlink only, used to allocate a Dedicated Control CHannel;
vi) Standalone Dedicated Control CHannel (SDCCH): bi-directional;
vii) Fast Associated Control CHannel (FACCH): bi-directional, associated with a Traffic CHannel;
viii) Slow Associated Control CHannel (SACCH): bi-directional, associated with a SDCCH or a Traffic CHannel;
ix) Cell Broadcast CHannel (CBCH): downlink only used for general (not point to point) short message information;
x) Notification CHannel (NCH): downlink only, used to notify mobile stations of VBS (Voice Broadcast Service) calls or VGCS (Voice Group Call Service) calls.
xi) Extended Coverage Broadcast Control CHannel (EC-BCCH): downlink only, used to broadcast Cell specific information in cells that support EC-GSM-IoT;
xii) Extended Coverage Synchronization CHannel (EC-SCH): downlink only, used to broadcast synchronization, BSS identification, EC-BCCH CHANGE MARK, Implicit Reject Status and RACH Access Control in cells that support EC-GSM-IoT;
xiii) Extended Coverage Paging CHannel (EC-PCH): downlink only, used to send page requests to EC capable Mobile Stations (MSs) in cells that support EC-GSM-IoT;
xiv) Extended Coverage Access Grant CHannel (EC-AGCH): downlink only, used to allocate packet resources to EC capable Mobile Stations (MSs) in cells that support EC-GSM-IoT;
xv) Extended Coverage Random Access CHannel (EC-RACH): uplink only, used to request uplink packet resources by EC capable Mobile Stations (MSs) in cells that support EC-GSM-IoT;
Two service access points are defined on signalling layer 2 which are discriminated by their Service Access Point Identifiers (SAPI) (see 3GPP TS 44.006):
i) SAPI 0: supports the transfer of signalling information including user-user information;
ii) SAPI 3: supports the transfer of user short messages.
Layer 3 selects the service access point, the logical control channel and the mode of operation of layer 2 (acknowledged, unacknowledged or random access, see 3GPP TS 44.005 and 3GPP TS 44.006) as required for each individual message.
Overview of control procedures
List of procedures
The following procedures are specified in this Technical Specification:
a) Clause 3 specifies elementary procedures for Radio Resource management:
- system information broadcasting (sub-clause 3.2.2);
- RR connection establishment (sub-clause 3.3):
- entering the dedicated mode: immediate assignment procedure (sub-clause 220.127.116.11);
- paging procedure for RR connection establishment (sub-clause 3.3.2);
- notification procedure (sub-clause 3.3.3).
- Procedures in dedicated mode and in group transmit mode (sub-clause 3.4):
- measurement report procedure (sub-clause 18.104.22.168);
- intracell change of channels (sub-clause 3.4.3);
- intercell change of channels (sub-clause 3.4.4);
- frequency redefinition procedure (sub-clause 3.4.5);
- channel mode change procedure (sub-clause 3.4.6);
- ciphering mode setting procedure (sub-clause 3.4.7);
- additional channel assignment procedure (sub-clause 3.4.8);
- partial channel release procedure (sub-clause 3.4.9).
- radio resources connection release (sub-clause 3.4.13);
- specific RR procedures for voice broadcast channels and voice group call channels (sub-clause 3.4.15);
- application procedures (sub-clause 3.4.21);
- RR procedures on CCCH and EC-CCCH related to temporary block flow establishment (sub-clause 3.5):
- packet paging procedure using CCCH (sub-clause 3.5.1);
- packet paging procedure using EC-CCCH (sub-clause 3.5.1a);
- packet access procedure using CCCH (sub-clause 3.5.2);
- packet access procedure using EC-CCCH (see sub-clause 3.5.2a);
- packet downlink assignment procedure using CCCH (sub-clause 3.5.3);
- packet downlink assignment procedure using EC-CCCH (sub-clause 3.5.5 ).
- RR procedures on DCCH related to temporary block flow establishment:
- Assignment to Packet Data Channel procedure (sub-clause 3.4.19);
- Network controlled cell reselection (sub-clause 3.4.20).
- RR procedure on DCCH related to MBMS:
- packet paging procedure for MBMS related to dedicated MBMS notification (sub-clause 3.4.27).
- RR procedures on CCCH related to MBMS: - packet paging procedure for MBMS notification using CCCH (sub-clause 22.214.171.124);
- packet access procedure for MBMS using CCCH (sub-clause 3.5.4).
- Procedures related to the simultaneous handover of dedicated and packet resources (sub-clause 3.7).
Clause 8 specifies actions to be taken on various error conditions and also provides rules to ensure compatibility with future enhancements of the protocol.
Applicability of implementations
The applicability of procedures of this technical specification for the mobile station is dependent on the services and functions which are to be supported by a mobile station. For the MS, the Revision level indicating Release 1999 is linked to the full support of the RR protocol and procedures in 3GPP TS 44.018 Release 1999.
Voice Group Call Service (VGCS) and Voice Broadcast Service (VBS)
For mobile stations supporting the Voice Group Call Service or the Voice Broadcast Service, it is explicitly mentioned throughout this technical specification if a certain procedure is applicable only for such a service and, if necessary, how mobile stations not supporting such a service shall behave.
For VGCS and VBS, the following possible mobile station implementations exist:
- support of listening to voice broadcast calls (VBS listening);
- support of originating a voice broadcast call (VBS originating);
- support of listening to voice group calls (VGCS listening);
- support of talking in voice group calls (VGCS talking. This always includes the implementation for VGCS listening);
- support of originating a voice group call (VGCS originating. This always includes the implementation for VGCS talking).
Apart from the explicitly mentioned combinations, all possible combinations are optional and supported by this technical specification.
A VGCS capable mobile station shall support USIM-based VGCS ciphering.
The related terms are used in this technical specification, if information on these implementation options is required.
General Packet Radio Service (GPRS)
For mobile stations supporting the General Packet Radio Service (GPRS), it is explicitly mentioned throughout the technical specification if a certain procedure is applicable only for such a service and, if necessary, how mobile stations not supporting such a service shall behave.
A GPRS MS may operate in one of the following MS operation modes, see 3GPP TS 23.060:
- MS operation mode A;
- MS operation mode B; or
- MS operation mode C.
The MS operation mode depends on the services that the MS is attached to, i.e., only GPRS or both GPRS and non- GPRS services, and upon the MS's capabilities to operate GPRS and other GSM services simultaneously. Mobile stations that are capable to operate GPRS services are referred to as GPRS MSs.
NOTE: Other GSM technical specifications may refer to the MS operation modes A, B, and C as GPRS class-A MS, GPRS class-B MS, and GPRS class-C MS.
It should be noted that it is possible that for a GPRS MS, the GMM procedures currently described in the present document do not support combinations of VGCS, VBS and GPRS. The possible interactions are not studied yet.
Multimedia Broadcast/Multicast Service (MBMS)
For mobile stations supporting the Multimedia Broadcast/Multicast Service (MBMS) feature, it is explicitly mentioned throughout the technical specification if a certain procedure is applicable only for such a service and, if necessary, how mobile stations not supporting such a service shall behave.
The support of dedicated mode MBMS notification is mandatory for mobile stations and optional for networks supporting the Multimedia Broadcast/Multicast Service (MBMS) feature. The dedicated mode MBMS notification consists of the Service Information Sending procedure and the MBMS announcement of mobile stations in dedicated mode.
Independently of what is stated elsewhere in this and other 3GPP specifications, mobile station support for PBCCH and PCCCH is optional for A/Gb-mode of operation. The network shall never enable PBCCH and PCCCH.