General comment: at any stage in the location updating process the MSC may receive an indication from the BSS that the MM transaction has been released. The MSC then sends an Abort signal to the VLR. Upon receipt of this message, the VLR shall follow one of two possible courses of action.
The two possible courses of action and the conditions determining which course shall be taken are as follows:
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If a successfully authenticated radio connection is already established before the Abort message is received, the VLR shall ignore the message.
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If a successfully authenticated radio connection has not been established before the Abort message is received, the VLR shall abort the Update Location Area process and return to the idle state.
Sheet 1: the location area updating process will be activated by receiving an Update Location Area indication from the MSC. If there are parameter errors in the indication, the process is terminated with the appropriate error sent in the Update Location Area response to the MSC. Else, the behaviour will depend on the subscriber identity received, either an IMSI or a TMSI.
The Automatic Device Detection (ADD) function is an optional feature that allows the HLR to be updated with the current User Equipment (IMEISV) and thus enables the network to configure the subscriber's equipment based on a predefined profile. The mechanism for the IMEISV retrieval by device management system (either from HLR or VLR) is outside the scope of this specification. As an optimisation, the VLR may optionally store whether or not the HLR supports the ADD feature and use this information to decide whether or not to send an update to the HLR.
The Paging Area function is an optional feature that allows the HLR to be updated with the current Paging Area (PgA) (see
clause 2.6). If supported, whenever the paging area changes, the VLR shall send a MAP Update Location request with the Paging Area parameter set to the location areas belonging to the new paging area. The Paging Area is then sent by the HLR (if available) to the VLR in the MAP Provide Roaming Number and may be used for paging optimisation after a MSC/VLR restart (see
TS 23.018).
Sheet 1: The usage of a Hop Counter is an optional optimization.
Sheet 2: at the decision
"HLR updating required?" the
"True" branch shall be taken if and only if one or more of the following conditions is true:
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Location Info Confirmed in HLR is false.
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Data Confirmed by HLR is false.
Sheet 2: : The execution of the test
"HLR supports ADD?" and the action
"set: skip subscriber data update" is an optional optimisation and depends on the presence of the relevant indication from the HLR that ADD functionality is supported. If this optimisation is not supported on the VLR or no indication is received, both are bypassed in which case processing continues at connector 4.
Sheet 2: The execution of the test
"HLR supports PgA?" and the action
"set: skip subscriber data update" depends on the presence of the relevant indication from the HLR that PgA functionality is supported.
Sheet 2: The
"Subscriber data dormant" flag is an optional parameter that shall at least be supported by VLR implementing the Mobile Terminating Roaming Retry feature (see
TS 23.018). A VLR not supporting this flag shall behave as if the flag is set to false.
Sheet 2: A VLR supporting the Mobile Terminating Roaming Retry feature sets the
"Cancel Location received" flag to false after authenticating the radio connection. This is used to determine whether to trigger MT roaming retry upon receipt of an incoming call, see
clause 7.3.2.1 of TS 23.018.
Sheet 3: the procedure Obtain_IMSI_VLR is specified in
TS 23.018.
The type of Location Update is retrieved in
TS 23.078 procedure 'Set_Notification_Type' and is returned into the 'Notify' variable; this information is necessary for the CAMEL Mobility Management event notification procedure
TS 23.078 'Notify_gsmSCF'.
