Content for TS 48.008 Word version: 18.0.0
1 Scope
1.1 References
1.2 Definitions and Abbreviations
2 Application to interface structures
2.1 The BSS Operation and Maintenance Application Part
2.2 The Direct Transfer Application Part
2.3 The BSS Management Application Part
2.4 Handling of abnormal events related to the BSSAP Header
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1 Scope p. 12
The present document specifies the layer 3 procedures used on the Base Station System (BSS) to Mobile-services Switching Centre (MSC) interface for control of GSM services.
For the purposes of call control and mobility management, messages are not interpreted at the Base Station System (BSS) which acts as a relay function. These messages and procedures are documented in TS 24.008, the only relevant issues covering these messages in the present document are those concerned with error conditions at the interface, and the headers that are required for the correct addressing of the messages. This is specified in more detail in TS 48.002.
The functional split between MSC and BSS is defined in TS 48.002 and states that the BSS is responsible for local radio resource allocation and in order to support this the required procedures between BSS and MSC are defined in detail in the present document.
3GPP TS 48.002 also states that the BSS is responsible for the scheduling of all CCCH/BCCH messages and therefore some procedures for providing the BSS with the necessary information to be passed on these channels for individual calls (i.e. paging) are defined in the present document, but the scheduling is not discussed.
This interface and consequently these layer 3 procedures are designed to support BSSs providing one or more cells.
1.1 References p. 12
The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
[1]
TR 21.905: "Vocabulary for 3GPP Specifications".
[2]
TS 23.003: "Numbering, addressing and identification".
[3]
TS 23.009: "Handover procedures".
[3a]
TS 23.032: "Universal Geographical Area Description (GAD)".
[4] (void)
[5]
TS 43.059: "Functional stage 2 description of Location Services (LCS) in GERAN".
[6]
TS 24.008: "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3".
[7] (void).
[8] (void).
[9] (void).
[10] (void).
[11] (void).
[12] (void).
[13] (void).
[14] (void).
[15] (void).
[16]
TS 48.002: "Base Station System - Mobile-services Switching Centre (BSS-MSC) interface; Interface principles".
[17]
TS 48.006: "Signalling transport mechanism specification for the Base Station System - Mobile-services Switching Centre (BSS-MSC) interface".
[18]
TS 48.020: "Rate adaption on the Base Station System - Mobile-services Switching Centre (BSS-MSC) interface".
[18a] (void).
[19]
TS 48.071: "Location Services (LCS); Serving Mobile Location Center - Base Station System (SMLC-BSS) interface; Layer 3 specification".
[19a]
TS 49.031: "Location Services (LCS); Base Station System Application Part LCS Extension (BSSAP-LE)".
[20] (void).
[21] (void).
[22] (void).
[23] (void).
[24] (void).
[25] (void).
[26] (void).
[27] (void).
[28]
TS 52.021: "Network Management (NM) procedures and messages on the A-bis Interface".
[29] (void).
[30] (void).
[31]
TS 25.413: "UTRAN Iu Interface RANAP signalling".
[32]
TS 44.018: "Mobile radio interface layer 3 specification; Radio Resource Control Protocol".
[33]
TS 25.331: "Radio Resource Control (RRC) protocol specification".
[34] (void).
[35] (void).
[36] (void).
[37]
ITU T Recommendation E.164: "The international public telecommunication numbering plan".
[38]
ITU T Recommendation X.25: "Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode and connected to public data networks by dedicated circuit".
[39]
TS 43.020: "Security-related network functions".
[40]
TS 43.073: "Support of Localised Service Area (SoLSA); Stage 2".
[41]
TS 52.008: "Telecommunication management; GSM subscriber and equipment trace".
[42] (void).
[43]
TS 45.002: "Multiplexing and multiple access on the radio path".
[44]
TS 26.103: "Speech codec list for GSM and UMTS".
[45]
TS 43.051: "GSM/EDGE Radio Access Network (GERAN) overall description; Stage 2".
[46]
TS 23.172: "Technical realization of Circuit Switched (CS) multimedia service UDI/RDI fallback and service modification; Stage 2".
[47]
TS 43.068: "Voice Group Call Service (VGCS); Stage 2".
[48]
TS 23.236: "Intra-domain connection of Radio Access Network (RAN) nodes to multiple Core Network (CN) nodes".
[49]
TS 23.216: "Single Radio Voice Call Continuity (SRVCC); Stage 2".
[50]
TS 22.220: "Service Requirements for Home NodeBs and Home eNodeBs".
[51]
TS 23.153: "Out of band transcoder control; Stage 2".
[52]
TS 23.251: "Network sharing - Architecture and functional description".
[53]
TS 29.280: "3GPP Sv interface (MME to MSC, and SGSN to MSC) for SRVCC ".
[54]
TS 23.284: "Local Call Local Switch; Stage 2".
[55]
TS 29.205: "Application of Q.1900 series to bearer independent Circuit Switched (CS) core network architecture; Stage 3".
[56]
TS 43.130: "Iur-g interface; Stage 2".
[57]
TS 36.413: "S1 Application Protocol (S1AP)".
[58]
TS 45.008: "Radio subsystem link control".
[59]
TS 36.300: "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2".
[60]
TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification"
[61]
TS 24.237: "IP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) Service Continuity; Stage 3"
[62]
TS 33.102: "3G Security; Security architecture".
[63]
TS 24.301: "Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)".
[64]
TS 28.062: "Inband Tandem Free Operation (TFO) of speech codecs; Service description; Stage 3"
1.2 Definitions and Abbreviations p. 14
For the purposes of the present document, the definitions and abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905.
- CS/PS coordination enhancements: refers to an improved CS/PS domain registration coordination function when rerouting is performed in a MOCN or in a GWCN configuration for network sharing. The improved CS/PS domain registration coordination is achieved by extended signalling between the BSS and the CN nodes (see TS 23.251).
- Network sharing: network sharing is an optional feature that allows different core network operators to connect to the same shared radio access network in a MOCN configuration, and to the same shared radio access network and core network nodes in a GWCN configuration (see TS 23.251). When network sharing is in use within a given cell, the network broadcasts within system information the PLMN identities of the PLMNs sharing the cell. A mobile station supporting network sharing uses this information for its PLMN (re)selection processes and indicates the selected PLMN to the BSS.
A over IP, using IP as the bearer of the user plane of A interface.
AoTDM
A over TDM, using TDM as the bearer of the user plane of A interface.
CSFB
Circuit Switched Fallback
CSG
Closed Subscriber Group
CSG Cell
A cell for which the reported access mode indicates "Closed access mode" as defined in [50].
EPS
Evolved Packet System
E-UTRAN
Evolved UTRAN
eNB
E-UTRAN NodeB
GCR
Global Call Reference
HSPA
High Speed Packet Access
GWCN
GateWay Core Network as defined in TS 23.251
Intra-BSS call
A mobile to mobile voice call involving two mobile stations connected to the same BSS.
LCLS
Local Call Local Switch
Local call
An Intra-BSS call that can be locally switched by the BSS.
Hybrid Cell
A cell for which the reported access mode indicates "Hybrid access Mode" as defined in [50].
MOCN
Multi Operator Core Network as defined in TS 23.251.
SRVCC
Single Radio Voice Call Continuity.
UTRAN
Universal Terrestrial Radio Access Network
2 Application to interface structures p. 15
The underlying transport mechanism defined to carry signalling information between the BSS and the MSC is the Message Transfer Part (MTP), and the Signalling Connection Control Part (SCCP) of Signalling System No.7.
The MTP and SCCP are used to support communication between the MSC and two conceptual entities within the BSS, these are:
- the BSS Operation and Maintenance Application Part (BSSOMAP);
- the BSS Application Part (BSSAP).
- the BSS Management Application Part (BSSMAP);
- the Direct Transfer Application Part (DTAP).
2.1 The BSS Operation and Maintenance Application Part p. 15
If operation and maintenance messages are transferred by means of this interface then they shall use SCCP messages. The application protocol for the Operation and Maintenance Application Part is defined in the 3GPP TS 52 series Technical Specifications. The routeing and addressing is provided by the SCCP and allows the MSC and the O&M centre to be addressed directly by the BSS using, for example, two E.164 numbers. The operator may also use an X.25 connection for the transfer of O&M messages between the BSS and the OMC. This option is not further discussed in the present document.
2.2 The Direct Transfer Application Part p. 15
The Direct Transfer Application Part (DTAP) is used to transfer call control and mobility management messages between the MSC and the MS. The DTAP information in these messages is not interpreted by the BSS. TS 48.002 contains more detail relating to the handling of DTAP messages at the BSS, the multiplexing of the messages onto the relevant signalling channels of the radio interface, and the use of the SCCP services.
Messages received from the MS are identified as DTAP by the Protocol Discriminator Information Element as described in TS 24.008, except for Initial Layer 3 messages (see subclause 3.1.16). The majority of radio interface messages are transferred across the BSS MSC interface by the DTAP, the exceptions being messages belonging to the Radio Resource (RR) management protocol.
2.3 The BSS Management Application Part p. 16
The BSSMAP supports all of the procedures between the MSC and the BSS that require interpretation and processing of information related to single calls, and resource management.
Some of the BSSMAP procedures result in, or are triggered by, Radio Resource (RR) management messages defined in TS 24.008. The BSSMAP procedures are described in subclause 3.
2.4 Handling of abnormal events related to the BSSAP Header p. 16
The BSSAP header is specified in TS 48.002. Several abnormal events may be detected by the receiver:
- use of a reserved value in the DLCI or discriminator;
- length octet with value zero;
- length octet with a value inconsistent with that indicated by the SCCP.
