22.0673GPPenhanced Multi Level Precedence and Pre-emption service (eMLPP)Stage 1TS
A maximum authorized precedence level is provided to a service subscriber after prior arrangements with the service provider. Service subscribers without an eMLPP subscription are assigned to a default priority level (in case of emergency calls, TS12, exceptions shall be possible).
The maximum authorized precedence level can be changed or the complete eMLPP service withdrawn at the subscriber’s request or for administrative reasons.
The definition of the priority level to be used as default level at mobile originated call establishment shall be registered in the network. This default level will be used if a subscriber has a subscription for a priority level higher than the lowest priority level and has not selected a priority level at call set‑up.
Registration can take place either by the service provider or with an appropriate control procedure by the subscriber.
If the subscriber requests a priority level higher than the maximum entitled one then the network shall reject this registration with an appropriate indication to the subscriber.
Erasure of a default priority level is done as a result of a new registration overruling, and thus effectively erasing the previous registration.
5.5 Network related service configuration
The allocation of eMLPP priority levels to the call set‑up classes and the possibility of pre‑emption of on‑going calls in case of congestion will be arranged by the network operator for a specific composition of the eMLPP service in a network. This is not related to one specific service subscriber.
An example is given in table 1 of clause 4.
The eMLPP shall be invoked automatically by the network at call set‑up.
The precedence level may be selected by the user on a per call basis. The user may select any precedence level up to and including her maximum authorized precedence level. The maximum authorized precedence level shall be stored on the SIM/USIM and the mobile station shall check that only an authorized level is used for set‑up. In addition, it shall be possible to verify in the network the level used at set‑up against the maximum authorized level.
If the user has not selected a precedence level at set‑up, the network shall apply the subscriber specific default precedence level.
If the user has selected a precedence level higher than the maximum authorized level, the maximum authorized precedence level shall be applied for the call.
5.9 Normal operation
At invocation of the eMLPP on a call set‑up, the network notes the call priority related to the call and decides on the respective actions to be taken, i.e. on queuing priority, fast call set‑up procedures and possibly pre‑emption in case of congestion of network resources. In case of pre‑emption the network shall release the lowest lower priority call and seize the necessary resources that are required to set‑up the higher priority call.
Once set for a call, the precedence level cannot be changed.
In the case of automatic answering of an incoming call with a sufficient priority level, the alerting indication to the calling party may not be provided in order shorten the set‑up time. In case of called mobile subscriber busy, the on‑going call shall be released if automatic answering applies (or set on call hold in case of a telephony call) to accept an incoming call of higher priority.
When pre‑emption applies, at handover to a congested cell, higher priority calls shall replace those of the lowest priority. The pre‑empted user shall receive an indication for congestion as defined in 3GPP TS 22.001.
A service subscriber may interrogate the range of priority levels he can use and the default priority level used for mobile originated call establishment.
5.11 Charging requirements
The utilized precedence level shall be able to be extracted from the event records if different from the default precedence level.