B.3 Off-network timers

24.2813GPPMission Critical Video (MCVideo) signalling controlProtocol specificationRelease 16TS

B.3.1 Timers in off-network group call

B.3.1.1 Basic call control

The table B.3.1.1-1 lists the timers used in basic call control, their start values, their limits, describes the cause of the start, and the action to take on normal stop and on expiry.

Table B.3.1.1-1: Timers in basic call control

Timer

Timer value

Cause of start

Normal stop

On expiry

TFG1 (wait for call announcement)

Default value: 150 millisecond

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG1" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a CALL PROBE message.

Reception of a CALL ANNOUNCEMENT message.

Send a CALL ANNOUNCEMENT message.

TFG2 (call announcement)

Calculated. Refer to section 9.3.2.4.1.1.

Commencement of group call.
Restarted every time a CALL PROBE message is received OR CALL ANNOUNCEMENT message is sent or received.

Termination of group call.

When the client Receives a CALL PROBE message or CALL ANNOUNCEMENT message, Re-calculate timer value and restart.

Send a CALL ANNOUNCEMENT message. Re-calculate timer value and restart.

TFG3 (call probe retransmission)

Default value: 40 millisecond

Depends on the characteristic of the D2D (D2D Sidelink period)

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG3" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a CALL PROBE message.

Reception of a CALL ANNOUNCEMENT message.

Or TFG1 Expires.

Or User releases the call.

Send a CALL PROBE message.

TFG4 (waiting for the user)

Default value: 30 seconds

Maximum value: 60 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG4" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Reception of CALL ANNOUNCEMENT message when not participating in the ongoing call.

Reception of User action (Accept or Reject).

Stop incoming call notification.

TFG5 (not present incoming call announcements)

Default value: 30 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG5" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Expiration of TFG4

Or User rejects the call.

Or User releases the call.

Reset group call state machine.

TFG6 (Max duration)

Calculated. Refer to section 9.3.2.4.1.2.

Commencement of group call

Termination of group call

Release the group call

B.3.1.2 Call type control

The table B.3.1.2-1 lists the timers used in call type control, their star values, describes the cause of start, and the action to take on normal stop and on expiry.

Table B.3.1.2-1: Call type control

Timer

Timer value

Cause of start

Normal stop

On expiry

TFG11 (emergency end retransmission)

Default value: 1 second

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG11" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a GROUP CALL EMERGENCY END message.

Send a GROUP CALL EMERGENCY END message Increment associated counter by 1.

If counter has reached limit, stop the timer.

TFG12 (imminent peril end retransmission)

Default value: 1 second

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFG12" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a GROUP CALL IMMINENT PERIL END message.

Send a GROUP CALL IMMINENT PERIL END message Increment associated counter by 1.

If counter has reached limit, stop the timer.

TFG13 (implicit downgrade emergency)

Calculated.

Refer to clause 9.3.3.4.1.1.

Upgrade of the call to emergency group call.

Downgrade of the call.

Downgrade the call.

TFG14 (implicit downgrade imminent peril)

Calculated.

Refer to clause 9.3.3.4.1.2.

Upgrade of the call to imminent peril call.

Downgrade of the call.

Downgrade the call.

B.3.2 Timers in off-network private call

The table B.3.2-1 lists the timers used in off-network private call, their start values, their limits, describes the cause of start, and the action to take on normal stop and on expiry.

Table B.3.2-1: Timers in off-network private call

Timer

Timer value

Cause of start

Normal stop

On expiry

TFP1 (private call request retransmission)

Default value: 40 millisecond

Depends on the characteristic of the D2D (D2D Sidelink period)

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFP1" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a PRIVATE CALL SETUP REQUEST message.

Reception of a PRIVATE CALL ACCEPT or PRIVATE CALL REJECT message.

Resend PRIVATE CALL SETUP REQUEST message. Increment associated counter by 1.

If counter has reached limit, assume the called client is not available. Terminate call setup.

TFP2 (waiting for call response message)

Default value: 30 seconds

Maximum value: 60 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFP2" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Reception of a PRIVATE CALL SETUP REQUEST message.

User responds to the incoming call notification.

Start TFP7 timer.

Send a PRIVATE CALL REJECT message

TFP3 (private call release retransmission)

Default value: 40 millisecond

Depends on the characteristic of the D2D (D2D Sidelink period)

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFP3" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a PRIVATE CALL RELEASE message.

Reception of PRIVATE CALL RELEASE ACK message.

Resend PRIVATE CALL RELEASE message. Increment associated counter by 1.

If counter has reached limit, assume the receiving client is not available anymore. Release the call.

TFP4 (private call accept retransmission)

Default value: 40 millisecond

Depends on the characteristic of the D2D (D2D Sidelink period)

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFP4" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

When the client sends a PRIVATE CALL ACCEPT message.

Reception of a PRIVATE CALL ACCEPT ACK message or RTP media.

Resend PRIVATE CALL ACCEPT message. Increment associated counter by 1.

If counter has reached limit, assume the receiving client is not available anymore

Notify call setup failure.

TFP5 (max duration)

Configurable.

Set to the value of "/<x>/OffNetwork/PrivateCall/MaxDuration" leaf node present in the service configuration as specified in 3GPP TS 24.483 [4].

Call establishment.

Call termination.

Terminate the call.

TFP7 (waiting for any message with same call identifier)

Default value: 1 second

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFP7" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Rejection of a call OR

Termination of a call OR

Call Failure.

Reset the call control state machine.

B.3.3 Timers in off-network broadcast call

The table B.3.3-1 lists the timers used in off-network broadcast call, their start values, their limits, describes the cause of start, and the action to take on normal stop and on expiry.

Table B.3.3-1: Timers in off-network broadcast call

Timer

Timer value

Cause of start

Normal stop

On expiry

TFB1 (max duration)

Default value: 300 seconds

Maximum value: 600 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFB1" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Start of the broadcast call.

Terminate the broadcast call.

TFB2 (broadcast retransmission)

Default value: 3 seconds

Maximum value: 10 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFB2" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Start of the broadcast call.

Broadcast call termination.

Send GROUP CALL BROADCAST message.

TFB3 (waiting for the user)

Default value: 30 seconds

Maximum value: 60 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFB3" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Receipt of GROUP CALL BROADCAST message when user response is required.

Response from user.

Terminate incoming call notification.

B.3.4 Timers in off-network emergency alert

The table B.3.4-1 lists the timers used in off-network emergency alert, their start values, their limits, describes the cause of start, and the action to take on normal stop and on expiry.

Table B.3.4-1: Timers in off-network emergency alert

Timer

Timer value

Cause of start

Normal stop

On expiry

TFE1 (Emergency Alert)

Default value: 30 seconds

Maximum value: 60 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFE1" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Receipt of GROUP EMERGENCY ALERT.

Receipt of GROUP EMERGENCY ALERT CANCEL.

Assume end of emergency state, remove associated user from the list.

TFE2 (emergency alert retransmission)

Default value: 5 seconds

Maximum value: 10 seconds

Configurable.

Set to the value of "/<x>/OffNetwork/Timers/TFE2" leaf node present in the UE initial configuration as specified in 3GPP TS 24.483 [4].

Transmission of GROUP EMERGENCY ALERT.

Transmission of GROUP EMERGENCY ALERT CANCEL.

Transmit GROUP EMERGENCY ALERT.

Annex C (normative):
Counters