Hi, frend.
The Enhanced Multi-Level Precedence and Pre-emption service (eMLPP) is a supplementary service offered by the GSM system. When the eMLPP feature is enabled, the MS with a high priority has advantages in terms of the call setup rate, call completion capability, and service continuity. When TCHs are insufficient, for example, during traffic peak hours, the calls with a higher priority can preempt the resources of the calls with a lower priority. (GBFD-115001 Enhanced Multi Level Precedence and Preemption(EMLPP))
When resources are insufficient, the eMLPP service ensures that the MSs with a high priority use the resources first. If the preempted MSs are not handed over to other channels, for example, if the site is an isolated site, the TCH resources in neighbor cells are insufficient, or the handovers have timed out, the measurement values of the counters related to call drop rate on TCH increase.
If the eMLPP feature is enabled, the cooperation from the CN is required to ensure the normal operation of eMLPP services.
The eMLPP services consist of two parts:
A call with any priority can use the fast call setup procedure. In the fast call setup procedure, authentication, encryption, and TMSI reassignment are omitted. Thus, the call setup time is reduced.
When network resources, including trunk circuits, signaling channels, and traffic channels, are insufficient, the calls with a higher priority are not released, but wait in a queue or even preempt the resources of the calls with a lower priority.
The eMLPP service is used to classify calls into groups with different priorities. The calls with a higher priority can enjoy better services, such as channel preemption and fast call setup. The eMLPP service offers a segmentation function for operators. By enabling this function, operators can provide different levels of services for subscribers with different priorities.
Thanks.
