Change Request Summary: TR 26.942 CR 0013 rev 2

Document Information

• CR Number: 0013 rev 2
• Release: Rel-20
• Category: B (addition of feature)
• Work Item: AMD_PRO-MED (previously FS_Energy_Ph2_MED)
• Source: Nokia
• Meeting: S4-260221 (SA4 WG4 meeting #135, February 2026)

Overview

This CR proposes a solution for optimizing media sessions based on UE energy consumption during mobility scenarios. The solution addresses Key Issue #6 (previously #5) by leveraging energy-related information from the network's Energy Information Function (EIF) to help Application Servers optimize media delivery in an energy-efficient manner.

Main Technical Contributions

1. Solution Mapping Update

• Added Solution #13 to the mapping table (Table 7.1-1)
• Solution #13 addresses Key Issue #6: Optimization of media sessions based on UE energy consumption

2. New Solution #13: Optimization of Media Sessions Based on UE Energy Consumption (Clause 7.15)

2.1 Use Case Scenario

The solution targets scenarios where a user wishes to consume media content (e.g., watching a 90-minute football match) during mobility with limited battery capacity. The system optimizes media delivery QoE based on energy consumption predictions to enable completion of the media session while conserving both UE and network energy.

2.2 Architecture and 5GC Role

The solution defines an architecture where the 5G Core (5GC) plays a central role by providing:

• Mobility Event Reporting and Forecasting: AMF notifies registered AFs about UE mobility events (handovers, access type changes, network area transitions)
• UE and Radio Capability Information: AMF/SMF provides Media AF with UE capabilities, supported RATs, and PDU Session characteristics
• Policy Control and QoS Adaptation: PCF interacts with Media AF and SMF to manage QoS policy changes affecting energy consumption
• Network Data Analytics: NWDAF/PCF shares traffic patterns, load predictions, and network conditions with Media AF
• Network Energy-Related Information Exposure: Energy Information AF obtains cell-specific energy constraints and power saving mode states via NEF

2.3 Functional Process

The solution defines a three-phase process:

Phase 1: UE Energy Information Collection
- Media-aware Application initiates media delivery session during mobility
- Energy Information Collector (EIC) instantiated in Media Session Handler gathers energy consumption data
- Context created including energy consumption prediction related to UE mobility (considering cell edge vs. center positioning)

Phase 2: Codec Adaptation Based on Energy Consumption and Mobility
- Media Session Handler requests predicted energy consumption from Energy Information AF
- Energy Information AF subscribes to EIF for energy consumption data from 5GC (per TS 23.501 clause 5.51)
- NWDAF analytics engine analyzes UE mobility pattern to predict energy consumption
- Media Session Handler selects energy-efficient media rendition/encoding parameters considering:
- Battery level
- Mobility pattern
- Media content type and duration
- Adaptation options include:
- Downlink: Selection between Adaptation Sets (MPEG-DASH) at different bitrates/resolutions
- Uplink: Adjustment of encoding bitrate
- RTC: Request to RTC AS for transcoding

Phase 3: Media Session Update and Delivery
- Media Session Handler informs Media Access Function of selected media encoding
- Media delivered using optimal parameters balancing energy efficiency and QoE

2.4 Detailed Procedures (Figure 7.15.3-2)

The call flow includes 22 steps:

Initial Setup (Steps 1-9):
- Media-aware Application requests media delivery session
- Media Session Handler coordinates with Media Access Function
- Transport connection established with Media AS
- Baseline energy-related information collection procedures

Energy Management Initialization (Steps 10-13):
- Media-aware Application initiates energy information collection considering mobility
- Energy Information Collector registers/subscribes with Energy Information AF
- Energy Information AF subscribes to UE mobility events from AMF

Parallel Media Delivery and Adaptation (Steps 14-22):
- Media delivery starts
- AMF notifies Energy Information AF of mobility events (handovers, access changes)
- EIF returns network-level energy information to Energy Information AF
- Energy Information AF reports network energy exposure and mobility-driven estimates to Energy Information Collector
- Media Session Handler processes inputs and decides on adaptation
- Media Session Handler selects appropriate media parameters
- Media Access Function informed of new parameters
- Adapted media delivery continues

3. Gap Analysis

Five key gaps identified requiring normative work:

1. Energy Information Collector subscription mechanism with Energy Information AF for mobility-tied energy estimations
2. Energy Information AF subscription to UE mobility events from AMF
3. Energy Information AF reporting of network energy exposure and mobility-driven estimates
4. Media Session Handler processing logic for adaptation decisions
5. Media Session Handler selection of media parameters based on energy info and mobility prediction

4. Potential Normative Requirements

Proposed normative work in TS 26.512:

New clauses specifying:
- Extensions to procedures and service-based interfaces at reference point E5 for Energy Information Collector subscription with Energy Information AF regarding mobility-tied energy estimations
- Extensions to procedures and service-based interfaces at reference point M5 for Energy Information AF reporting of network energy exposure and mobility-driven estimates to Energy Information Collector

5. Summary

The solution enables UE optimization of media delivery session energy consumption during mobility by:
- Leveraging Energy Information AF and EIF collaboration with 5G Core and Media Application Provider
- Utilizing 5GC service-based interfaces for exchanging energy-related information, mobility events, and session parameters
- Enabling Media Delivery System to react dynamically to UE mobility context and network energy state
- Maintaining high-quality media experience while minimizing energy consumption during transitions across cells, RATs, or network conditions