The consumer of QoS Sustainability analytics may request the NWDAF analytics information regarding the QoS change statistics for an Analytics target period in the past in a certain area or the likelihood of a QoS change for an Analytics target period in the future in a certain area. The consumer can request either to subscribe to notifications (i.e. a Subscribe-Notify model) or to a single notification (i.e. a Request-Response model).
The service consumer may be a NF (e.g. AF).
The request includes the following parameters:
Analytics ID = "QoS Sustainability";
Target of Analytics Reporting: "any UE";
Analytics Filter Information containing:
QoS requirements (mandatory):
5QI (standardized or pre-configured), and applicable additional QoS parameters and the corresponding values (conditional, i.e. it is needed for GBR 5QIs to know the GFBR); or
the QoS Characteristics attributes including Resource Type, PDB, PER and their values;
Location information (mandatory): an area or a path of interest. The location information could reflect a list of waypoints;
Optional maximum number of objects;
Analytics target period: relative time interval, either in the past or in the future, that indicates the time period for which the QoS Sustainability analytics is requested;
Reporting Threshold(s), which apply only for subscriptions and indicate conditions on the level to be reached for the reporting of the analytics, i.e. to discretize the output analytics and to trigger the notification when the threshold(s) provided in the analytics subscription are crossed by the expected QoS KPIs. The level(s) relate to value(s) of the QoS KPIs defined in TS 28.554, for the relevant 5QI:
for a 5QI of GBR resource type, the Reporting Threshold(s) refer to the QoS flow Retainability KPI;
for a 5QI of non-GBR resource type, the Reporting Threshold(s) refer to the RAN UE Throughput KPI.
An acceptable deviation from the threshold level in the non-critical direction (i.e. in which the QoS is improving) may be set to limit the amount of signalling.
In a subscription, the Notification Correlation Id and the Notification Target Address.
The NWDAF collects the corresponding statistics information on the QoS KPI for the relevant 5QI of interests from the OAM, i.e. the QoS flow Retainability or the RAN UE Throughput as defined in TS 28.554.
If the Analytics target period refers to the past:
The NWDAF verifies whether the triggering conditions for the notification of QoS change statistics are met and if so, generates for the consumer one or more notifications.
The analytics feedback contains the information on the location and the time for the QoS change statistics and the Reporting Threshold(s) that were crossed.
If the Analytics target period is in the future:
The NWDAF detects the need for notification about a potential QoS change based on comparing the expected values for the KPI of the target 5QI against the Reporting Threshold(s) provided by the consumer in any cell in the requested area for the requested Analytics target period. The expected KPI values are derived from the statistics for the 5QI obtained from OAM. OAM information may also include planned or unplanned outages detection and other information that is not in scope for 3GPP to discuss in detail.
The analytics feedback contains the information on the location and the time when a potential QoS change may occur and what Reporting Threshold(s) may be crossed.
Average UE bitrate in the cell (Payload data volume on RLC level per elapsed time unit on the air interface, for transfers restricted by the air interface), per timeslot, per cell, per 5QI and per S-NSSAI.
The NWDAF outputs the QoS Sustainability analytics. Depending on the Analytics target period, the output consists of statistics or predictions. The detailed information provided by the NWDAF is defined in Table 6.9.3-1 for statistics and Table 6.9.3-2 for predictions.
The consumer requests or subscribes to analytics information on "QoS Sustainability" provided by NWDAF. The parameters included in the request are described in clause 6.9.1.
The consumer may include multiple sets of parameters in order to provide different combinations of "Location information" and "Analytics target period" when requesting QoS Sustainability analytics.
The NWDAF verifies whether the triggering conditions are met and derives the requested analytics. The NWDAF can detect the need for notification based on comparing the requested analytics of the target 5QI against the Reporting Threshold(s) provided by consumer in any cell over the requested Analytics target period.