6 Mobile initiated unstructured supplementary service data operations
24.0903GPPRelease 17Stage 3TSUnstructured Supplementary Service Data (USSD)
6.1 Normal operation
The MS invokes an USSD request by sending a REGISTER message to the network containing a ProcessUnstructuredSS‑Request invoke component.
The receiving network entity shall pass the data received in the request to the application handling USSD operations and shall wait for the response of the application. The application may either terminate the dialogue or may request several times further information in order to perform the requested operation (see figures 6.1 and 6.2).
When the application requests more information to process the request, the network shall initiate an USSD request (see subclause 5.1.1), using the on‑going transaction (see figure 6.2). The MS shall return the user’s response in a FACILITY message containing a return result component. The network shall pass the data received in the response to the application. If the MS is unable to process the request received from the network, it shall return an error indication by sending a FACILITY message containing a return error component.
When the application terminates the dialogue, the network shall clear the transaction by sending a RELEASE COMPLETE message containing a return result component. The MS may also clear the transaction at any time by sending a RELEASE COMPLETE message upon request of the user.
If the network is unable to process the request received from the MS, it shall clear the transaction by sending a RELEASE COMPLETE message containing a return error component. Error values are specified in 3GPP TS 24.080.
The MS shall not initiate USSD operations in parallel to any call independent supplementary service transaction. Only one transaction for USSD operations per user is allowed at a time. However, the MS is allowed to initiate USSD operations in parallel to call related transactions.
MS Network
REGISTER
————————————————————————————————————————>
Facility (Invoke = ProcessUnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
RELEASE COMPLETE
<————————————————————————————————————————
Facility (Return result = ProcessUnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
RELEASE COMPLETE
<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Facility (Return error (Error))
RELEASE COMPLETE
<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Facility (Reject (Invoke_problem))
Figure 6.1: Mobile initiated USSD operation, network does not request further information
NOTE: The MS may clear the transaction at any time by sending a RELEASE COMPLETE upon request of the user.
MS Network
REGISTER
————————————————————————————————————————>
Facility (Invoke = ProcessUnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
FACILITY
<————————————————————————————————————————
Facility (Invoke = UnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
FACILITY
————————————————————————————————————————>
Facility (Return result = UnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
FACILITY
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – ->
Facility (Return error (Error))
FACILITY
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – ->
Facility (Reject (Invoke_problem))
.
.
.
RELEASE COMPLETE
<————————————————————————————————————————
Facility (Return result = ProcessUnstructuredSS-Request (ussd-DataCodingScheme, ussd-String))
RELEASE COMPLETE
<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Facility (Return error (Error))
RELEASE COMPLETE
<- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
Facility (Reject (Invoke_problem))
Figure 6.2: Mobile initiated USSD operation, network requests further information
NOTE 1: The MS may clear the transaction at any time by sending a RELEASE COMPLETE upon request of the user.
NOTE 2: The network may request further information several times. Only one information request is shown. The network initiated USSD operation may also be an USSD notification. Only a network initiated USSD request is shown.
6.2 Cross phase compatibility
6.2.1 Network only supports protocol version 1 of unstructured supplementary service data operations
If a mobile initiated USSD request using protocol version 2 is rejected by the network, and the reason for the rejection is indicated either by the problem code "unrecognized operation" or a cause "Facility rejected", the MS shall assume that the network only supports protocol version 1 of USSD operations. The MS shall re‑attempt the request by using the appropriate protocol version 1 USSD operation without a SS version indicator if the unstructured data entered by the user can be coded as an IA5 string.
6.2.2 Mobile station only supports protocol version 1 of unstructured supplementary service data operations
A MS supporting only protocol version 1 invokes an USSD request by sending a REGISTER message to the network containing a ProcessUnstructuredSsData invoke component without a SS version indicator. In this situation the network is not allowed to start a network initiated USSD operation. If the application requires such an operation for its proper function, the USSD operation sent by the MS shall be rejected by the application. The network shall terminate the transaction by sending a RELEASE COMPLETE message with cause "Facility rejected" (see 3GPP TS 24.008).
Annex A (informative):
Change history
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Change history |
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Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New version |
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Apr 1999 |
Transferred to 3GPP CN1 |
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CN#03 |
Approved at CN#03 |
3.0.0 |
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CN#11 |
Approved at CN#11 |
4.0.0 |
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CN#16 |
References updated |
4.0.1 |
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CN#16 |
Rel-5 created after CN#16 |
5.0.0 |
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CN#26 |
Rel-6 created after CN#26 |
6.0.0 |
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CT#36 |
Upgraded unchanged from Rel-6 |
7.0.0 |
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CT#42 |
Upgraded unchanged from Rel-7 |
8.0.0 |
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2009-12 |
Update to Rel-9 version (MCC) |
9.0.0 |
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2011-03 |
Update to Rel-10 version (MCC) |
10.0.0 |
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2012-09 |
Update to Rel-11 version (MCC) |
11.0.0 |
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2014-09 |
Update to Rel-12 version (MCC) |
12.0.0 |
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2015-12 |
Update to Rel-13 version (MCC) |
13.0.0 |
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2017-03 |
Update to Rel-14 version (MCC) |
14.0.0 |
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2018-06 |
Update to Rel-15 version (MCC) |
15.0.0 |
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2020-07 |
Update to Rel-16 version (MCC) |
16.0.0 |
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2022-03 |
CT#95e |
– |
– |
– |
– |
Update to Rel-17 version (MCC) |
17.0.0 |