Implementation of a R2 client Kotlin library

[dsilhavy]

Description

A question on the R2 client implementation for Android based UEs. Do we have a Github issue for what is needed to implement a R2 client yet? On Fraunhofer side we might be able to spend time on this to extend our existing Android 5GMS stack.

From what I remember data like QoE metrics, Consumption reports are still reported via M5 by the Media Session Handler. But there were additional data/metrics that are supposed to be reported by a R2 client to the R2 server?

If we have a description of what needs to be done on the UE side I can already check internally if we can contribute such a feature.

[rjb1000]

You're right that most of the client data reporting for 5GMS happens implicitly: either through M5 interactions (metrics reporting, consumption reporting, invocation of Dynamic Policy and Network Assistance APIs).

The one explicit use case we have for direct data reporting at reference point R2 is for ANBR-based Network Assistance. This is a niche feature defined in clauses 4.0.5 and 5.9 of TS 26.501, and further specified in clause 5.6.2 of TS 26.510 where the Media Session Handler seeks Network Assistance from the RAN by directly invoking modem APIs. The data reporting aspect is summarised in clause D.6 of TS 26.501.

However, bear in mind that all of the 5GMS data reports would form part of a (future) 5GMS instantiation of the UE data collection, reporting and event exposure system.

In the near term, we just have the set of generic data reports defined in TS 23.247 and TS 26.532 to play with. In this generic instantiation of the EVEX architecture,the Direct Data Reporting Client can be any process running on the UE, such as background service, collecting information about the system and reporting it to the network.

In our reference implementation, we have so far only implemented one data report type: UE communication. The UE reports how many bytes of data it has downlinked and how many it has uplinked.

As a starting point, this information could be collected by the UE and reported to the generic Data Collection AF via reference point R2.

But I suggest constructing it as a reusable Kotlin library that can later be instantiated in the Media Session Handler to provide other types of data report, such as the one specified for 5G Media Streaming.