Content for TS 23.087 Word version: 18.0.0
1 Scope
2 References
3 Definitions and abbreviations
3.1 Definitions
3.2 Abbreviations
4 General
4.1 Activation of UUS components
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1 Scope p. 6
The present document gives the stage 2 description of the User-to-User signalling supplementary services.
The User-to-user supplementary service is divided into 3 different services:
- Service 1 (UUS1)
- Service 2 (UUS2)
- Service 3 (UUS3)
2 References p. 6
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.
3 Definitions and abbreviations p. 6
3.1 Definitions p. 6
For the purposes of the present document, the following terms and definitions apply.
Burst parameter:
parameter indicating the absolute maximum number of UUS 3 service related user information messages that can be sent at intervals indicated by the value of timer T2-UUS3
Remote network:
network of the remote subscriber
Remote subscriber:
for service 1 and 2 the remote subscriber is the called party of a call to which the served subscriber activates the UUS supplementary service. For service 3 the remote subscriber can be either the called or the calling party of an established call to whom the use of the UUS supplementary service is requested by the served subscriber
Served subscriber:
subscriber who has a provision of the UUS supplementary service and who activates the UUS supplementary service. For service 1 and 2 the served subscriber is always the calling subscriber, for service 3 either the calling or the called subscriber can be the served subscriber
Serving network:
network of the served subscriber
User-to-User Information (UUI):
information transferred by using the UUS supplementary service
UUS Service:
UUS services (Service 1, 2 and 3) are components of the UUS supplementary service. If the UUS supplementary service is provided to a subscriber, he can handle the UUS services independently within a call
3.2 Abbreviations p. 7
For the purposes of the present document, the following abbreviations apply:
ACM
Address Complete Message
ANM
ANswer Message
CON
CONnect
CPG
Call ProGress
IAM
Initial Address Message
MS
Mobile Station
REL
RELease
SIFOC
Send Info For Outgoing Call
SRI
Send Routing Info
UUI
User-to-User Information
UUS
User-to-User Signalling
UUS1
User-to-User Signalling Service 1
UUS2
User-to-User Signalling Service 2
UUS3
User-to-User Signalling Service 3
Further GSM related abbreviations are listed in GSM 01.04.
4 General p. 7
The UUS supplementary service allows the transfer of UUI to a remote subscriber over the signalling channel in association with a call to this subscriber. The UUS supplementary service is divided in Service 1, Service 2 and Service 3.
The UUS Service 1 allows the transfer of UUI embedded within Call Control messages.
The UUS Service 2 allows the transfer of UUI with a specific User-to-user message after the served subscriber has received an address complete indication and prior to the answer indication from the B-side.
The UUS Service 3 allows the transfer of UUI with a specific User-to-user message during an active call.
For the use of the UUS supplementary service in GSM PLMNs the support of UUS capabilities within the inter exchange signalling system (e.g. ISUP) is necessary. However this is out of scope of the present document.
4.1 Activation of UUS components p. 7
If any of the UUS Services 1, 2 or 3 shall be used within a call, the UUS capabilities have to be activated by the served subscriber either when initiating this outgoing call (Service 1, 2 and 3) or during an established call (Service 3).
The UUS capabilities for a call can be requested by means of an implicit request or an explicit request. UUS Service 1 can be requested either implicitly or explicitly. Service 2 and 3 can only be requested explicitly.
4.1.1 Implicit request p. 7
The UUS1 service is activated implicitly by the presence of UUI in the set-up request from the mobile station. The network shall transfer the received UUI transparently to the B-side. For the purpose of UUS service 1 implicitly requested, no explicit check for the availability of UUS capabilities at the destination network has to be performed by the originating network.
If the calling subscriber has UUS 1 provisioned and implicitly requested, the network shall transfer all UUI contained in call control messages.
If the calling subscriber has UUS1 not provisioned, the contained UUI shall be discarded by the serving MSC. The call shall be established without further restrictions.
The served subscriber shall not be informed whether the implicit request was successful or not.
4.1.2 Explicit request p. 8
Any UUS Service can be explicitly activated by the served subscriber within the set-up request initiating a mobile originated call. In addition UUS Service 3 can be activated during an established call with a Facility message. A UUS Service 1 request can be accompanied by appropriate UUI.
The network shall check for the availability of UUS capabilities for the call by passing the UUS request and the eventually accompanied UUI to the remote side. If a UUS Service is available for the call an appropriate "UUS provided" indication for this UUS Service shall be sent within the first backward message from the remote side.
A UUS Service shall not be activated for the call if a "UUS not provided" indication or no indication about the availability of this UUS Service is received from the remote side.
Service 3 can be explicitly activated during an active call by both parties. This may lead to a collision of activation requests. The collision of activation requests occurs when there is an outstanding request for service 3 and a subsequent request is received from the remote user. The entity (user or network) that observes the collision shall reject the second request with Facility message. This leads to the rejection of both requests.
4.1.3 UUS required option p. 8
As an option at call set-up the served subscriber can specify whether the requested UUS Service is required or not required for the call. If service 1 is implicitly requested or if service 3 is requested during the call, it cannot be requested as required.
If the served subscriber has specified that one of the UUS services is required for the call and this UUS service can not be activated by the network, the call attempt of the served subscriber shall be cleared.
If the served subscriber has specified that one of the UUS services is not required for the call and this UUS service can not be activated by the network, the call establishment shall be continued.
