This page documents the inFlux DB schema used in the E Release for the KPM (and other) information collected from E2 Simulator.

Version	Author	Comments	Date
0.1	Agustin Pozuelo	Initial DRAFT, calling for comment!	24 Sep 2021

DRAFT / Proposal

This schema is open for discussion and contribution from the O-RAN community

Summary / Goals

The goal is to have a generic schema definition for xApps to access timeseries data obtained via E2SM/KPM and possibly the other E2SM protocols.

References

E2SM-KPM specs
TS 28.552 "5G performance measurements"
InfluxDB glossary - https://docs.influxdata.com/influxdb/v1.8/concepts/glossary
Viavi RIC Test User Manual

Glossary

SDL: Shared Data Layer, a term referring to the services and schemas used to share data among xApps

Essential InfluxDB terms:

Database: the highest level unit of storage
Measurement: a table inside a database
Data point: a row inside a Measurement table.
Field: a sort of column of a Measurement table, with name and type of data.
- Note that not all fields need to be present in all data points
Tag: a metadata field that is indexed so queries on them are performant

Guidelines

For items not explicitly defined in O-RAN specs, look for relevant 3GPP specs.
Field and tag names should be brief because the may pose a direct impact on InfluxDB performance at high loads.
For proprietary/enrichment data fields, use a brief vendor prefix e.g. "Viavi."

Proposed Schema for E2SM/KPM data

Database name: “E2SM-KPM”

For the labelling of fields we will be using names from E2SM/KPM v2.0 (MeasurementLabel) and TS 28.552 "5G performance measurements" as much as possible.

Following the general ideas in from TS 28.552, using short labels, organized in hierarchical form <topic>[.<subtopic>].<name>

KPM Measurement tables:

"CellReports" table containing the following fields:
1. Timestamp
2. PLMN (tag)
3. KPMNodeID (tag) - The KPM Node identification in string form to accomodate the many binary variants (maybe an hex dump?)
4. S-NSSAI (tag?) - useful to identify slices?
5. NRCellIdentity (tag?)
  
  Any of the fields defined for cell reports in TS 28.552, for example the following are provided by RIC Test scenario generator:
6. DRB.UEThpDl - Average DL throughput in Kb/s
7. RRU.PrbUsedDl / RRU.PrbAvailDl
8. RRU.PrbUsedUl / RRU.PrbAvailUl
9. QosFlow.PdcpPduVolumeUl - UL PDCP PDU Data Volume (amount of kilobytes in the reporting period)
10. QosFlow.PdcpPduVolumeDl - DL PDCP PDU Data Volume (amending inconsistency in the case of the final "L" in TS 28.552)
  
  And proprietary extensions:
11. Viavi.Geo.x - Non standard / Viavi proprietary extension / External enrichment
12. Viavi.Geo.y
13. Viavi.Geo.z
"UeReports" measurement table containing the following fields:
1. Timestamp
2. UE.Id - String representation to accomodate the many forms.
  Note: A "UE id resolution" xApp may be needed to match the same UE on different measurements and possibly producing unique ids for this field
3. Slice.Id
4. DRB.UEThpDl - TS 28.552 Average DL UE throughput
5. RRU.PrbUsedDl - TS 28.552 DL PRB used for data traffic
6. Viavi.Geo.x”, .y, .z... Viavi proprietary extensions
7. RF.serving.Id - May be just the PCI or resolved into NRCellIdentity
8. RF.serving.RSRP (Loosely based on LTE specs)
9. RF.serving.RSRQ
10. RF.serving.RSSINR
11. RF.nb1.CellId - 1st neighbour id
12. RF.nb1.RSRP, etc. 1st neighbour signal levels
13. RF.nb2.CellId - 2nd neighbour id
14. RF.nb2.RSRP, etc. 2nd neighbour signal levels
"cellMeasReport" cell load measurement table has the following fields:
1. Timestamp
2. DLOccupyPRBNum – 3GPP supported
3. CellDLMACRate – proprietary
4. ULSINR – proprietary
5. MCS – proprietary
6. PDCPOccupBuffer – proprietary
7. PDCPUnusedBuffer – proprietary
8. DLPacketDiscardNum – proprietary
9. DLPacketSDUNum – 3GPP supported
10. DLPacketLossNum – 3GPP supported
11. DLMACRate – proprietary