SIST ETS 300 392-10-11 E2:2003

• Abstract:

  Analysis of predicted needs for digital trunked systems in Europe; definition of services to be provided; analysis of spectrum req ments; characteristics of relevant interfaces Contains: TETRA 03.60 to 03.85

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.070.10 - Terrestrial Trunked Radio (TETRA)
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Mandate: T-172-1A
• Ref Project: ETSI ETS 300 392-10-11 ed.2 (2000-02) - Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 10: Supplementary services stage 1; Sub-part 11: Call Waiting (CW)

SIST ETS 300 392-10-11 E2:2003 is the Slovenian adoption of ETS 300 392-10-11 Edition 2 for Terrestrial Trunked Radio (TETRA) Voice plus Data (V+D). It specifies the stage 1 user-level description of the Call Waiting (CW) supplementary service, so readers can see what the service does from the user's point of view and how a busy called user can deal with an incoming individual call.

What does SIST ETS 300 392-10-11 E2:2003 specify?

SIST ETS 300 392-10-11 E2:2003 defines the Call Waiting supplementary service (SS-CW) for TETRA as provided by European operators. It describes the service, the normal and exceptional procedures, the interactions with other TETRA supplementary services, and the inter-working considerations.

The scope is limited to stage 1 service behavior. That means the standard explains the service in operational terms, but not the detailed human interface, and it also leaves charging principles outside its scope.

The document is organized into these main parts:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Definitions and abbreviations
• Clause 4 - SS-CW stage 1 specification
  • 4.1 Description
  • 4.2 Procedures
  • 4.3 Interactions with other supplementary services
  • 4.4 Inter-working considerations
  • 4.5 Overall SDL

What are the key requirements of SIST ETS 300 392-10-11 E2:2003?

SIST ETS 300 392-10-11 E2:2003 focuses on what happens when a user is already busy and another individual call arrives. The main practical point is that the standard tells the network when to offer the call, when to reject it, and how the served user can accept, reject, ignore, or clear it.

Service availability and provisioning

Clause 4.2.1 says SS-CW may be provided per individual subscriber or as a network-wide option for all TETRA individual subscribers. The subscription applies to all basic services where SS-CW is relevant, which matters because implementation and customer activation need to match the supported service set.

Withdrawal is handled by the service provider for administrative reasons or at the request of the served user when the service was individually provided. The network does not need to send a special notice to subscribers when that happens.

Invocation while the user is busy

Clause 4.2.2.2 states that when SS-CW is active and a new individual call arrives while the called user is already busy, the network offers the call unless the maximum number of additional calls has already been reached. In practice, this means the network must manage busy-state call presentation, not just call completion.

The served user invokes SS-CW by sending a positive response within the same time allowed for a basic call response. If the user is in an individual call, the standard recommends freeing resources first, for example by clearing the active call or using Call Hold (HOLD), before connecting the waiting call.

Timing and waiting calls

Clause 4.2.2.3 links SS-CW handling to timer T2, and says that if the initial values of T304 and T2 are below 30 seconds, they should be set to at least 30 seconds except for specific applications. For implementers, this ties the waiting-call behavior to network timing and terminal response behavior.

If the served user has more than one waiting call, the network may allow that, but the maximum number is a network option and one waiting call is recommended. That choice affects capacity planning, user experience, and terminal behavior.

Exceptional cases

Clause 4.2.3 covers failures and timeout behavior. If SS-CW is not subscribed, activation can fail and the network must provide the reason. If the maximum number of waiting calls is already reached, the network rejects the invocation and clears the call with the called party busy cause.

If the served user deactivates SS-CW, the network should avoid presenting new calls when it knows the user is busy. If a call is still presented and the user tries to invoke SS-CW, the invocation is rejected.

If a waiting call is neither accepted nor rejected before timer T2 expires, the network clears the call. The same clause also covers the case where user C clears the call, or where the network cannot support restoration after a location change.

Interactions with other services

Clause 4.3 sets the interaction rules with other TETRA supplementary services. Some services have no interaction with SS-CW, while others must be coordinated carefully.

The most operationally important points are:

• Call Forwarding Unconditional (SS-CFU) takes precedence over SS-CW.
• Call Forwarding On Busy (SS-CFB) can be invoked when the user does not take the waiting call or clears it as busy.
• Call Forwarding on No Reply (SS-CFNRy) can be triggered by the first expiry among its own timer, T2, or basic call timer T304 while the call is still waiting.
• Call Hold (HOLD) can be used to free resources so the user can accept a waiting call.
• Call Completion to Busy Subscriber (CCBS) and Call Completion on No Reply (CCNR) have specific conditions that depend on whether SS-CW has been invoked.
• Pre-emptive Priority Call (PPC) can still be accepted as a waiting call, even if that exceeds the normal maximum number of waiting calls.
• Discreet Listening (DL) and Ambience Listening (AL) have special handling so monitoring does not block SS-CW use.

Inter-working

Clause 4.4 says SS-CW must work across different TETRA networks and with external networks. The serving network passes the SS-CW notification and disconnect causes to user C when needed, and if migration or location change is not supported, waiting calls are cleared with the appropriate reason.

For external networks, the gateway relays SS-CW notification to the distant party, but it does not invoke the external network's own call waiting service on behalf of TETRA SS-CW.

What terms does SIST ETS 300 392-10-11 E2:2003 define?

Clause 3 defines a small set of service-specific terms and abbreviations that are central to implementation:

• served user - the user who can invoke SS-CW when already busy.
• user A - the user already in an individual call with the served user.
• user C - the user who places the incoming individual call that may wait.
• timer T2 - the timer for how long a waiting call may remain pending before the network clears it.
• SS-CW - the call waiting supplementary service itself.
• MS - Mobile Station.
• SDL - (Functional) Specification and Description Language.
• SS - Supplementary Service.

Who uses SIST ETS 300 392-10-11 E2:2003?

SIST ETS 300 392-10-11 E2:2003 is used by people who specify, build, and operate TETRA supplementary services. That includes network operators, service providers, terminal and Mobile Station implementers, and engineers working on call control behavior in TETRA Voice plus Data systems.

It is also useful for quality managers and buyers who need to confirm how a TETRA product handles busy subscribers, waiting calls, call forwarding, and service interactions. In practice, it helps them check whether a system supports the Call Waiting behavior expected in a TETRA network.

What changed in SIST ETS 300 392-10-11 E2:2003 from the previous edition?

SIST ETS 300 392-10-11 E2:2003 corresponds to ETS 300 392-10-11 Edition 2. The document history shows a first edition from April 1996, a one-step approval procedure in 1999, and the second edition in February 2000.

Which standards are used with SIST ETS 300 392-10-11 E2:2003?

The normative references name the documents that support the service description and procedures:

• CCITT Recommendation I.130 - the method for characterizing telecommunication services, used for the service description framework.
• ITU-T Recommendation Z.100 - the Specification and Description Language (SDL), used for the behavioral models.
• ETS 300 392-2 - the TETRA Air Interface (AI), used for basic call behavior and timer T304 references.
• ETS 300 392-9 - the general requirements for TETRA supplementary services, which supplies the shared definitions used by SS-CW.

What does the SIST ETS 300 392-10-11 E2:2003 document contain?

The document contains a service description, procedure rules, interaction rules, inter-working provisions, and SDL diagrams for SS-CW. Figures 1 and 2 give the overall SDL for invocation, operation, and activation, which is useful for implementation and verification work.

Clause 4.2 gives the call-handling procedures, including normal and exceptional cases such as maximum waiting calls, deactivation, timeouts, and location change. Clause 4.3 explains how SS-CW behaves alongside other supplementary services, which is the part engineers usually need when integrating multiple TETRA features.

Clause 4.4 describes how SS-CW behaves across different TETRA networks and through external gateways. That makes the document relevant for interoperability testing, roaming behavior, and gateway design.

SLOVENSKI STANDARD
01-december-2003
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VWRULWYHVWRSQMH±SRGGHOýDNDMRþLNOLF&:
Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 10: Supplementary
services stage 1; Sub-part 11: Call Waiting (CW)
Ta slovenski standard je istoveten z: ETS 300 392-10-11 Edition 2
ICS:
33.070.10 Prizemni snopovni radio Terrestrial Trunked Radio
(TETRA) (TETRA)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 392-10-11
TELECOMMUNICATION February 2000
STANDARD Second Edition
Source: TETRA Reference: RE/TETRA-03001-10-11
ICS: 33.020
Key words: Data, radio, speech, stage 1, supplementary service, TETRA
Terrestrial Trunked Radio (TETRA);
VoiceplusData(V+D);
Part 10: Supplementary services stage 1;
Sub-part 11: Call Waiting (CW)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Internet: [e-mail] - http://www.etsi.org
Tel.:[phone]- Fax:[phone]
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 2000. All rights reserved.

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ETS 300 392-10-11: February 2000
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 Standards Making Support Dept." at the address shown on the title page.

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ETS 300 392-10-11: February 2000
Contents
Foreword.5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
3.2.1 General abbreviations .8
3.2.2 Supplementary service abbreviations.8
4 SS-CW stage 1 specification.8
4.1 Description .8
4.1.1 General description .8
4.1.2 Qualifications on applicability to telecommunication services .8
4.2 Procedures.8
4.2.1 Provision/withdrawal.8
4.2.2 Normal procedures.9
4.2.2.1 Activation, deactivation, definition, registration,
interrogation and cancellation.9
4.2.2.1.1 Activation/Deactivation.9
4.2.2.1.2 Definition .9
4.2.2.1.3 Registration.9
4.2.2.1.4 Interrogation.9
4.2.2.1.5 Cancellation .9
4.2.2.2 Invocation.9
4.2.2.3 Operation .9
4.2.3 Exceptional procedures.10
4.2.3.1 Activation, deactivation, definition, registration,
interrogation and cancellation.10
4.2.3.1.1 Activation/Deactivation.10
4.2.3.1.2 Definition .10
4.2.3.1.3 Registration.10
4.2.3.1.4 Interrogation.11
4.2.3.1.5 Cancellation .11
4.2.3.2 Invocation and operation.11
4.2.3.2.1 Invocation.11
4.2.3.2.1.1 Maximum number of waiting calls
reached .11
4.2.3.2.1.2 SS-CW deactivated .11
4.2.3.2.2 Operation .11
4.2.3.2.2.1 Waiting call cleared by the served
user .11
4.2.3.2.2.2 Call cleared by the network.12
4.2.3.2.2.3 No resources available .12
4.2.3.2.2.4 Waiting call ignored by the served
user .12
4.2.3.2.2.5 Waiting call clearing by user C.12
4.2.3.2.2.6 Location change.12
4.3 Interactions with other supplementary services .12
4.3.1 Calling Line Identification Presentation .12
4.3.2 Calling/Connected Line Identification Restriction .12
4.3.3 Connected Line Identification Presentation.12
4.3.4 Call Report.13
4.3.5 Talking Party Identification .13
4.3.6 Call Forwarding Unconditional (SS-CFU).13

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ETS 300 392-10-11: February 2000
4.3.7 Call Forwarding On Busy (SS-CFB) . 13
4.3.8 Call Forwarding on No Reply (SS-CFNRy). 13
4.3.9 Call Forwarding on Not Reachable (SS-CFNRc). 14
4.3.10 List Search Call (LSC) . 14
4.3.11 Call Authorized by Dispatcher (CAD). 14
4.3.12 Short Number Addressing (SNA). 14
4.3.13 Area Selection (AS) . 14
4.3.14 Access Priority (AP). 14
4.3.15 Priority Call (PC) . 14
4.3.16 Call Hold (HOLD). 15
4.3.17 Call Completion to Busy Subscriber (CCBS). 15
4.3.18 Late Entry (LE). 15
4.3.19 Transfer of Control (TC) . 15
4.3.20 Pre-emptive Priority Call (PPC) . 15
4.3.21 Include Call (IC) . 16
4.3.22 Advice of Charge (AC). 16
4.3.23 Barring of Outgoing Calls (BOC) . 16
4.3.24 Barring of Incoming Calls (BIC) . 16
4.3.25 Discreet Listening (DL) . 16
4.3.26 Ambience Listening (AL). 16
4.3.27 Dynamic Group Number Assignment (DGNA) . 16
4.3.28 Call Completion on No Reply (CCNR). 16
4.3.29 Call Retention (CRT). 17
4.4 Inter-working considerations . 17
4.4.1 Inter-working between different TETRA networks . 17
4.4.2 Inter-working with external networks . 17
4.5 Overall SDL . 17
History. 21

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ETS 300 392-10-11: February 2000
Foreword
This European Telecommunication Standard (ETS) has been produced by the Terrestrial Trunked Radio
(TETRA) Project of the European Telecommunications Standards Institute (ETSI).
This ETS is a multi-part standard and will consist of the following parts:
Part 1: "General network design";
Part 2: "Air Interface (AI)";
Part 3: "Interworking at the Inter-System Interface (ISI)";
Part 4: "Gateways basic operation";
Part 5: "Peripheral Equipment Interface (PEI)";
Part 6: "Line connected Station (LS)";
Part 7: "Security";
Part 9: "General requirements for supplementary services";
Part 10: "Supplementary services stage 1";
Part 11: "Supplementary services stage 2";
Part 12: "Supplementary services stage 3";
Part 13: "SDL model of the Air Interface (AI)";
Part 14: "Protocol Implementation Conformance Statement (PICS) proforma specification".
Transposition dates
Date of adoption of this ETS: 14 January 2000
Date of latest announcement of this ETS (doa):
30 April 2000
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 October 2000
Date of withdrawal of any conflicting National Standard (dow): 31 October 2000

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ETS 300 392-10-11: February 2000
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ETS 300 392-10-11: February 2000
1 Scope
This European Telecommunication Standard (ETS) defines the stage 1 description of the call waiting
supplementary service (SS-CW) for the Terrestrial Trunked Radio (TETRA) as provided by European
operators. The stage 1 description is an overall service description from the user point of view but does
not deal with the details of the human interface itself (see CCITT Recommendation I.130 [1]).
SS-CW permits a called user to acknowledge an incoming individual call while he is already busy.
Subsequently that user shall have the choice to accept, reject or ignore that incoming call.
This ETS specifies the service description of the supplementary service and the procedures to be
expected with successful and unsuccessful outcomes. In addition this ETS specifies the interactions
with other TETRA supplementary services and inter-working considerations.
Charging principles are outside the scope of this ETS.
2 Normative references
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 latest
edition of the publication referred to applies.
[1] CCITT Recommendation I.130: "Method for the characterization of
telecommunication services supported by an ISDN and network capabilities of
an ISDN".
[2] ITU-T Recommendation Z.100: "CCITT Specification and description language
(SDL)".
[3] ETS 300 392-2: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 2: Air Interface (AI)".
[4] ETS 300 392-9: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 9: General requirements for supplementary services".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the definitions of ETS 300 392-9 [4] apply, except for that of served user,
which is given below together with other ones which also apply:
served user: user who may invoke the supplementary service (i.e. acknowledge an incoming individual
while he is busy, instead of clearing it).
timer T2: measures the waiting time for the offered call from user C to be either accepted or cleared by
the served user B after SS-CW has been invoked. This timer is a network basic call timer. It corresponds
to the basic call timer T304 on the called user side (see clause 14 of ETS 300 392-2 [3]).
user A: user engaged in an individual call with the served user (this call can be in any state).
NOTE: There is no user A when the call in which the served user is engaged when he
receives an incoming individual call is a group call.
user C: user who has originated an individual call to the served user while that served user is busy
(i.e. the served user may invoke the call waiting supplementary service for the call from user C).

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ETS 300 392-10-11: February 2000
3.2 Abbreviations
3.2.1 General abbreviations
For the purposes of this ETS, the following general abbreviations apply:
ISDN Integrated Services Digital Network
MS Mobile Station
SDL (Functional) Specification and Description Language
SS Supplementary Service
NOTE: The abbreviation SS is only used when referring to a specific supplementary service.
3.2.2 Supplementary service abbreviations
For the purposes of this ETS, the following supplementary service abbreviations apply:
CAD Call Authorized by Dispatcher
CCBS Call Completion to Busy Subscriber
CFB Call Forwarding on Busy
CFNRc Call Forwarding on Not Reachable
CFNRy Call Forwarding on No Reply
CFU Call Forwarding Unconditional
CW Call Waiting
4 SS-CW stage 1 specification
4.1 Description
4.1.1 General description
SS-CW permits a called user to acknowledge an incoming individual call while he is already busy. That
call shall then be qualified as a waiting call. Subsequently that user shall have the choice to accept,
reject or ignore the waiting call.
4.1.2 Qualifications on applicability to telecommunication services
This supplementary service shall be applicable to all circuit mode individual teleservices and bearer
services.
4.2 Procedures
4.2.1 Provision/withdrawal
The provision of SS-CW shall be on a per individual subscriber basis, or as a network option general for
all (TETRA) individual subscribers. The corresponding subscriptions shall be valid for all basic services for
which SS-CW applies (see subclause 4.1.2).
The supplementary service shall be withdrawn by the service provider:
- for administrative purposes; or
- at the request of the served user, if individually provided.
No specific information shall then be given to the subscribers by the network.

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ETS 300 392-10-11: February 2000
4.2.2 Normal procedures
4.2.2.1 Activation, deactivation, definition, registration, interrogation and cancellation
4.2.2.1.1 Activation/Deactivation
The CW supplementary service shall be activated by the service provider upon provision.
The CW supplementary service shall be deactivated by the service provider upon withdrawal.
The served user should also be able to activate/deactivate the service after provision.
4.2.2.1.2 Definition
Not applicable.
4.2.2.1.3 Registration
Not applicable.
4.2.2.1.4 Interrogation
Not applicable.
4.2.2.1.5 Cancellation
Not applicable.
4.2.2.2 Invocation
If SS-CW has been activated for the served user, when a new individual call is addressed to that user
and the network has determined that such user is already engaged in a call (i.e. that user is then in the
busy state whether he participates in an individual call or in a group call), the network shall offer that
call to him unless it has already reached the maximum number of such additional calls.
NOTE 1: In ISDN, the case just addressed (where the network cannot present a new additional
call when the called user is busy) is one of those corresponding to the situation defined
as "Network Determined User Busy" (NDUB).
When the served user is offered such incoming individual call (from user C) while being busy, he shall
be able to invoke SS-CW. He shall do so in sending a positive response to the offered call within the
same predefined period of time as for sending a basic call response.
The same shall apply if the network offers a new incoming individual call to the served user without
knowing that he is in the busy state.
NOTE 2: The served user may be in the busy state without the network knowing it when the
served user participates in a group call.
The served user may be able to invoke SS-CW for more than one incoming individual call. However
the maximum number of waiting calls at any one time per busy subscriber shall be a network option,
and it is recommended that that maximum number be one.
4.2.2.3 Operation
When the called user has invoked SS-CW for a call (incoming individual):
- except for specific applications if the initial values of the basic call timers T304 (see clause 14 of
ETS 300 392-2 [3]) in his terminal equipment and T2 in the network are less than 30 seconds, they
should be set at least to 30 seconds;
- the network shall apply the individual basic call procedure for informing user C that:

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ETS 300 392-10-11: February 2000
- the basic call hook selection is on/hook off signalling;
- the called user has been offered the call.
- in addition the network shall notify user C that SS-CW has been invoked for his call.
If the served user is participating in an individual call, with user A, he should free resources
(i.e. especially air interface resources in the case of a MS) before requesting the network to connect
the waiting call from user C. To do so: either:
- he or user A shall clear the (active) individual call; or
- he shall invoke the call hold individual supplementary service.
If the served user is participating in a group call without being the call owner, according to the group call
procedures, he will be able to immediately leave that call and answer the waiting call without affecting the
ongoing group call. If he is the call owner, it is an implementation matter whether he will be able to
immediately leave the group call to answer the waiting call without first having first either cleared the group
call or transferred its control to another group member - using the supplementary service transfer of
control.
To accept a waiting call (after having freed resources following the above recommendation if the active
call was an individual call), the served user shall use the basic call procedure.
Any previous waiting indication to the served user should then be removed in the served user MS/LS.
If the served user has invoked SS-CW for more than one call, he shall be able to accept any such waiting
call, unless that call has been cleared in the meantime. The network shall connect that call:
if
- the served user has not changed location since he has invoked SS-CW for that call;
or if
- the served user has changed location since he has invoked SS-CW for that call and both his
terminal equipment and the network support the optional SS-CW location change procedure.
NOTE 1: See subclause 4.2.3.2 for the case where the network cannot satisfy the request
because the served user has changed location since he has invoked SS-CW for the
call and the network does not support the SS-CW location change procedure.
NOTE 2: If user C changes location while the call is waiting, the call restoration procedure for
basic call may apply.
4.2.3 Exceptional procedures
4.2.3.1 Activation, deactivation, definition, registration, interrogation and cancellation
4.2.3.1.1 Activation/Deactivation
The served user activation request may fail when SS-CW has not been subscribed for that user.
The network shall then indicate such failure to the served user in giving him the corresponding reason.
4.2.3.1.2 Definition
Not applicable.
4.2.3.1.3 Registration
Not applicable.
SIST ETS 30
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