5 User-to-User Signalling (UUS); remote mobile subscriber side

24.0873GPPRelease 17Stage 3TSUser-to-User Signalling (UUS) supplementary service

If the network has received a non-zero SS screening indicator from the remote MS, the description in the subclauses 5.1 to 5.3 applies.

If the network has received a zero SS screening indicator from the remote MS, three cases exist:

If UUS service was requested as „UUS required" during the call establishment, then the SETUP message will not be sent to the remote MS.

If UUS service was requested as „UUS not required" during the call establishment, then the SETUP message will be sent to the remote MS without the Facility information element including the UUS service activation request.

If UUS service was requested during an active call, then the Facility information element including the request of UUS service activation will not be sent to the remote MS.

5.1 UUS1

5.1.1 Operation when explicitly activated, UUS required

In this subclause the operation of UUS1, explicitly activated and with the indication "UUS required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————- Facility (Invoke=UserUserService (UUS1, UUS required)), User-user (Note 1)

. . ALERTING —————————————————————————————————————————> Facility (Return Result), User-user (Note 1), (Note 2)

ALERTING – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – > (Note 3)

CONNECT —————————————————————————————————————————> User-user (Note 1), (Note 2)

CONNECT – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – > (Note 3)

. . DISCONNECT / RELEASE COMPLETE / RELEASE <—————————————————————————————————————————> User-user (Note 1), (Note 3), (Note 4)

Figure 12: Request for explicit activation of UUS1, UUS required

NOTE 1: The User-user information element is optional.

NOTE 2: The Return Result component in the Facility information element may be sent either in the ALERTING or in the CONNECT message.

NOTE 3: If the MS B does not respond with an explicit service 1 acceptance or rejection, ALERTING or CONNECT message does not include a Return Result component. The following DISCONNECT message clears the call. See information on Cause values in Annex A.

NOTE 4: Under normal conditions DISCONNECT message is used for clearing the call, but also RELEASE or RELEASE COMPLETE message may be used as the first call clearing message.

5.1.2 Operation when explicitly activated, UUS not required

In this subclause the operation of UUS1, explicitly activated and with the indication "UUS not required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————- Facility (Invoke=UserUserService (UUS1, UUS not required)), User-user (Note 1)

. . ALERTING —————————————————————————————————————————> Facility (Return Result), User-user (Note 1), (Note 2)

ALERTING / CONNECT – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – > Facility (Return Error)

CONNECT —————————————————————————————————————————> User-user (Note 1), (Note 2)

. . DISCONNECT / RELEASE COMPLETE / RELEASE <—————————————————————————————————————————> User-user (Note 1), (Note 3)

Figure 13: Request for explicit activation of UUS1, UUS not required

NOTE 1: The User-user information element is optional.

NOTE 2: The Return Result component in the Facility information element may be sent either in the ALERTING or in the CONNECT message.

NOTE 3: Under normal conditions DISCONNECT message is used for clearing the call, but also RELEASE or RELEASE COMPLETE message may be used as the first call clearing message.

5.2 UUS2

5.2.1 Operation, UUS required

In this subclause the operation of UUS2, with the indication "UUS required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————– Facility (Invoke=UserUserService (UUS2, UUS required))

. . ALERTING —————————————————————————————————————————> Facility (Return Result)

ALERTING – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – > (Note 1)

DISCONNECT / RELEASE COMPLETE / RELEASE <- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – Cause (Note 1)

USER INFORMATION <—————————————————————————————————————————-> User-user, More data (Note 2)

. . CONNECT —————————————————————————————————————————->

Figure 14: Request for explicit activation of UUS2, UUS required

NOTE 1: If the MS B does not respond with an explicit service 2 acceptance or rejection, ALERTING message does not include a Return Result component. The following DISCONNECT message clears the call. See information on Cause values in Annex A.

NOTE 2: User-user information element is mandatory and More data information element is optional in USER INFORMATION message.

5.2.2 Operation, UUS not required

In this subclause the operation of UUS2, with the indication "UUS not required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————– Facility (Invoke=UserUserService (UUS2, UUS not required))

. . ALERTING —————————————————————————————————————————> Facility (Return Result)

ALERTING – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – > Facility (Return Error)

USER INFORMATION <—————————————————————————————————————————-> User-user, More data (Note 1)

. . CONNECT —————————————————————————————————————————->

Figure 15: Request for explicit activation of UUS2, UUS not required

NOTE 1: User-user information element is mandatory and More data information element is optional in USER INFORMATION message.

5.3 UUS3

5.3.1 Activation when originating a call

5.3.1.1 UUS required

In this subclause the activation of UUS3 when originating a call, with the indication "UUS required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————– Facility (Invoke=UserUserService (UUS3, UUS required))

. . CONNECT —————————————————————————————————————————-> Facility (Return Result)

CONNECT – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – ->

DISCONNECT <- – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – Cause (Note 1)

Figure 16: Request for explicit activation of UUS3 when originating a call, UUS required

NOTE 1: If the MS B does not respond with an explicit service 3 acceptance or rejection, DISCONNECT message is sent to the MS B to clear the call. See information on Cause values in Annex A.

5.3.1.2 UUS not required

In this subclause the activation of UUS3 when originating a call, with the indication "UUS not required", is described at the remote mobile subscriber side.

MS B NETWORK SETUP <—————————————————————————————————————————– Facility (Invoke=UserUserService (UUS3, UUS not required))

. . CONNECT —————————————————————————————————————————-> Facility (Return Result)

CONNECT – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -> Facility (Return Error)

Figure 17: Request for explicit activation of UUS3 when originating a call, UUS not required

5.3.2 Activation during an active call

In this subclause the activation of UUS3 during an active call is described at the remote mobile subscriber side.

MS B NETWORK Active call <—————————————————————————————————————————->

. . FACILITY <—————————————————————————————————————————– Facility (Invoke=UserUserService (UUS3, UUS not required))

FACILITY —————————————————————————————————————————-> Facility (Return Result)

FACILITY – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – -> Facility (Return Error (Error)) (Note 1)

Figure 18: Request for explicit activation of UUS3 during an active call

NOTE 1: If the remote party rejects the service request or does not respond with an explicit service 3 acceptance of rejection, the FACILITY message includes Facility information element with Return Error component indicating error "rejectedByUser". If the network rejects the request, the error value shall be "rejectedByNetwork".