ETSI ETS 300 902 ed.1 (1997-04)

SLOVENSKI STANDARD
SIST ETS 300 902 E1:2003
01-december-2003

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Digital cellular telecommunications system (Phase 2+) (GSM); Technical realization of

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Key words: Digital cellular telecommunications system, Global System for Mobile communications (GSM)

Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the

Whilst every care has been taken in the preparation and publication of this document, errors in content,

typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to

"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Foreword .......................................................................................................................................................5

1 Scope ..................................................................................................................................................7

1.1 Normative references ..........................................................................................................7

1.2 Abbreviations .......................................................................................................................7

2 General description .............................................................................................................................8

3 Network Architecture...........................................................................................................................9

4 CBE Functionality................................................................................................................................9

5 CBC Functionality................................................................................................................................9

6 BSC Functionality..............................................................................................................................10

7 BTS Functionality ..............................................................................................................................10

8 MS Functionality................................................................................................................................10

9 Protocols and Protocol Architecture..................................................................................................11

9.1 CBC-BSC Primitives ..........................................................................................................13

9.1.1 Identification of a message ...........................................................................13

9.1.2 WRITE-REPLACE Request/Indication..........................................................14

9.1.3 KILL Request/Indication ................................................................................15

9.1.4 REPORT Response/Confirm ........................................................................15

9.1.5 STATUS-CBCH-QUERY Request/Indication................................................15

9.1.6 STATUS-CBCH-QUERY Response/Confirm................................................15

9.1.7 STATUS-MESSAGE-QUERY Request/Indication ........................................16

9.1.8 STATUS-MESSAGE-QUERY Response/Confirm ........................................16

9.1.9 REJECT Response/Confirm .........................................................................16

9.1.10 RESTART-INDICATION Request/Indication.................................................16

9.1.11 RESET Request/Indication............................................................................17

9.1.12 FAILURE-INDICATION Request/Indication ..................................................17

9.1.13 SET-DRX Request/Indication........................................................................17

9.1.14 SET-DRX- REPORT Response/Confirm ......................................................18

9.2 Parameters ........................................................................................................................18

9.2.1 Message-Identifier.........................................................................................18

9.2.2 Old-Serial-Number ........................................................................................18

9.2.3 New-Serial-Number.......................................................................................18

9.2.4 Number-of-Pages..........................................................................................18

9.2.5 Cell-List .........................................................................................................18

9.2.6 Channel Indicator ..........................................................................................18

9.2.7 Category........................................................................................................18

9.2.8 Repetition-Rate .............................................................................................19

9.2.9 No-of-Broadcasts-Requested........................................................................19

9.2.10 No-of-Broadcasts-Completed-List.................................................................19

9.2.11 Cell-Identifier .................................................................................................19

9.2.12 Schedule-Period............................................................................................20

9.2.13 Reserved-Slots..............................................................................................20

9.2.14 Failure-List.....................................................................................................20

9.2.15 CBCH-Loading-List .......................................................................................20

9.2.16 Cause ............................................................................................................21

9.2.17 Diagnostic......................................................................................................21

9.2.18 Data Coding Scheme ....................................................................................21

9.2.19 CBS-Message-Information-Page n ...............................................................21

9.2.20 CBS-Message-Information-Length n ............................................................ 21

9.2.21 Recovery-Indication ...................................................................................... 22

9.3 Message Format on BTS-MS Interface ............................................................................ 22

9.3.1 General Description...................................................................................... 22

9.3.2 Message Content.......................................................................................... 22

10 SMSCB Index ................................................................................................................................... 25

Annex A (informative): Protocols for interconnecting CBC and BSC ..................................................... 27

History......................................................................................................................................................... 28

This European Telecommunication Standard (ETS) has been produced by the Special Mobile Group

(SMG) Technical Committee (TC) of the European Telecommunications Standards Institute (ETSI).

This ETS defines the Cell Broadcast short message service (CBS). It defines the primitives over the Cell

Broadcast Centre - Base Station System (CBC-BSS) interface and the message formats over the Base

Station System - Mobile Station (BSS-MS) interface for Teleservice 23 within the digital cellular

This ETS is a GSM technical specification version 5, which incorporates GSM Phase 2+

enhancements/features to the version 4 GSM technical specification. The ETS from which this Phase 2+

The contents of this ETS is subject to continuing work within TC-SMG and may change following formal

TC-SMG approval. Should TC-SMG modify the contents of this ETS, it will be resubmitted for OAP by

ETSI with an identifying change of release date and an increase in version number as follows:

y the third digit is incremented when editorial only changes have been incorporated in the

x the second digit is incremented for all other types of changes, i.e. technical enhancements,

This European Telecommunication Standard (ETS) describes the Cell Broadcast short message service

(CBS). It defines the primitives over the Cell Broadcast Centre - Base Station System (CBC-BSS)

interface and the message formats over the Base Station System - Mobile Station (BSS-MS) interface for

This ETS incorporates by dated and undated reference, provisions from other publications. These

normative references are cited at the appropriate places in the text and the publications are listed

hereafter. For dated references, subsequent amendments to or revisions of any of these publications

apply to this ETS only when incorporated in it by amendment or revision. For undated references, the

[10] GSM 08.52: "Digital cellular telecommunications system; Base Station Controller

The CBS service is analogous to the Teletex service offered on television, in that like Teletex, it permits a

number of unacknowledged general messages to be broadcast to all receivers within a particular region.

CBS messages are broadcast to defined geographical areas known as cell broadcast areas. These areas

may comprise of one or more cells, or may comprise the entire PLMN. Individual CBS messages will be

assigned their own geographical coverage areas by mutual agreement between the information provider

and the PLMN operator. CBS messages may originate from a number of Cell Broadcast Entities (CBEs),

which are connected to the Cell Broadcast Centre. CBS messages are then sent from the CBC to the

The CBS message comprises of 82 octets, which, using the default character set, equates to

93 characters. Up to 15 of these messages (pages) may be concatenated to form a macromessage. Each

page of such macromessages will have the same message identifier (indicating the source of the

message), and the same serial number. Using this information, the MS is able to identify and ignore

CBS messages are broadcast cyclically by the BTS at a frequency and for a duration specified by the

information provider. The frequency at which messages are repeatedly transmitted will be dependent on

the information that they contain; for example, it is likely that dynamic information such as road traffic

information, will require more frequent transmission than weather information. The repetition rate will also

be affected by the desire for messages to be received by high speed mobiles which rapidly traverse cells.

All suitably equipped mobiles within the catchment area of the transmitting BTS will be able to receive the

CBS messages may be broadcast on two different cell broadcast channels, which are characterized by

different QoS. A MS is always able to read the basic channel (see [8]). The reading of the extended

channel may collide with other tasks of the MS. Therefore the probability of receiving a CBS message on

the extended channel is smaller than on the basic channel. The reading of the extended channel for MSs

To permit mobiles to selectively display only those messages required by the MS user, CBS messages

are assigned a message class which categorises the type of information that they contain and the

language in which the message has been compiled. Through the use of appropriate MMI, the user is then

able to ignore message types that he does not wish to receive, e.g. advertising information or messages

- message transfer on link 4 is described in GSM 04.12 and the timing of messages transferred on

The functionality of the CBE is outside of the scope of GSM Specifications; however it is assumed that the

CBE is responsible for all aspects of formatting CBS, including the splitting of a CBS message into a

As the CBC (and any originating point for cell broadcast short messages) is regarded as a node outside

the PLMN, only the requirements placed upon the CBC by CBS functionality are specified by this ETS.

The CBC may be connected to several BSCs. The CBC may be connected to several CBEs. The CBC

shall be responsible for the management of cell broadcast short messages including:

- initiating broadcast by sending fixed length cell broadcast short messages to a BSC for each

language provided by the cell, and where necessary padding the message with the appropriate

- determining the set of cells/BTSs to which a message should be broadcast, and indicating within

- determining the time at which a message should cease being broadcast and subsequently

- determining the cell broadcast channel, on which the message should be broadcast.

To work efficiently on the interfaces, the BSC - which is normally controlling more than one cell of a

broadcast area - should be used as a concentrator as far as CB message handling is concerned. Hence,

the CBC should work on lists of cells when issuing CB related requests towards the BSC.

The BSC shall interface to only one CBC. A BSC may interface to several BTSs as indicated by

- providing an indication to the CBC when the desired repetition rate cannot be achieved;

- providing to the CBC acknowledgement of successful execution of commands received from the

- reporting to the CBC failure when a command received from the CBC is not understood or cannot

- transferring CBS information to each appropriate BTS via a sequence of 4 SMS BROADCAST

- optionally generating Schedule Messages, indicating the intended schedule of transmissions (see

- optionally receiving CBCH Load Indication messages and reacting by broadcasting a burst of

scheduled SMSCB messages or by suspending the broadcast for a period indicated by BTS (see

To work efficiently on the interfaces, the BSC should forward CB related messages to the CBC using cell

The BTS is responsible for conveying CBS information received via SMS BROADCAST REQUEST or

- Optionally generating CBCH Load Indication messages, indicating an underflow or overflow

The MS is responsible for recombination of the blocks received via the radio path to reconstitute the cell

broadcast short message. The precise method of display of cell broadcast short messages is outside the

- discard sequences transferred via the radio path (see GSM 04.12) which do not consist of

- have the ability to discard CBS information which is not in a suitable data coding scheme;

- have the ability to discard a message which has a message identifier indicating that it is of subject

- have the ability to ignore repeat broadcasts of messages already received (message has not

changed since it was last broadcast i.e. sequence number has not changed within the message's

- have the ability to transfer a message via the R interface when the R interface is supported;

- optionally enter SMSCB DRX mode based upon received Schedule Messages (see GSM 04.12);

- optionally skip reception of the remaining block(s) of a cell broadcast message which do(es) not

Commands interpreted by the BSC will result in a sequence of 4 SMS BROADCAST REQUEST

messages or 1 SMS BROADCAST COMMAND message being sent to a BTS, which in turn result in a

sequence of 4 messages being transferred via the BTS-MS interface (see GSM 04.12).

With the SMS BROADCAST REQUEST mode of operation, the 88 octet fixed length CBS page which is

specified in subclause 9.3 is split into four 22 octet blocks which are carried in SMS BROADCAST

Figure 2 illustrates the protocol architecture and the scope of the various GSM Specifications for the SMS

With the SMS BROADCAST COMMAND mode of operation, the BSC sends to the BTS in one single

message the 88 octet fixed length CBS page. The BTS then splits the page into four 22 octet blocks, adds

the sequence number (see GSM 04.12) and transmits the four resulting blocks on the air.

Figure 3 illustrates the protocol architecture and the scope of the various GSM Specifications for the SMS

The term primitive is used to indicate "an abstract, implementation independent interaction between a

service user and a service provider" (see CCITT X.210). For the CBC-BSC interface, the service provider

would be the protocol interconnecting CBC and BSC. A Primitive may therefore be viewed as an abstract,

implementation independent request/indication or response/confirm interaction between the service user

(CBC or BSC) and the service provider (protocol). A set of primitives for use between the CBC and BSC is

specified appropriate to the functionality assigned to the CBC and BSC in clauses 5 and 6. No mandatory

protocol between the CBC and the BSC is specified by GSM, this is a matter of agreement between CBC

and PLMN operators. GSM 03.49 (see also annex A of this ETS) provides example protocol stacks using

NOTE: In the following definitions, M indicates "mandatory parameter" and O indicates

Within a CBC-BSC interface, a message is uniquely identified by the quartet (message_identifier,

serial_number, Cell Identifier, Channel Indicator). This means that even when two messages have the

same semantic contents (for example the same weather forecast) but in different languages or coding

schemes, they are considered as different and must therefore be identified by a different quartet.

The serial number is managed cyclically and therefore this does not prevent to re-use the same quartet for

a different message when the serial number have been incremented a sufficient number of times. How to

This unique identification of a message across the CBC-BSC interface is used in all the primitive defined

hereafter. This means that the quartet will be implicitly or explicitly present in every interface primitive

This unique quartet will be referred in the rest of the document as the "message reference".

This primitive is sent by the CBC to the BSC. The CBC will use this primitive to either cause a new

If no old serial number is present then the primitive will be interpreted by the BSC as an instruction to

broadcast a new message in all the cells of the Cell list and on the channel derived by the Channel

Indicator (see the clause on parameters that describes the implicit value of the Channel Indicator when

not present in the message). The BSC will build as many message references as the number of cells in

the list. These message references will be used in particular in the subsequent write_replace and kill

If an old serial number is present, then the primitive will cause all information currently associated with the

combination of message identifier, serial number, Channel Indicator and the list of cells in the Cell list to

be deleted from the cells in the BSC (i.e. for all cells provided in the Cell-List parameter) and be replaced

All cells which should perform the broadcasting are mentioned in the Cell-List parameter.

The broadcast of the referenced message in the cells which are not mentioned in the Cell-List remains

unaffected. The BSC will build as many message references as the number of cells in the list. These

references will be used in particular in the subsequent write_replace and kill primitives.

When a message reference is derived from a primitive without any old serial number (write primitive) and

the message reference is already known by the BSC for certain cells in the list, the primitive will be

rejected with the cause "message reference already used". The list of cells where the message reference

If no category is present, the default category is interpreted by the BSC, see the parameter clause.