5G-Advanced - 5.5G Evolution
5G-Advanced represents the evolution of 5G towards enhanced capabilities and 6G preparation. It starts with Rel-18 (2024), continues with Rel-19 (2025), and Rel-20 (2026).
Key Features
5G-Advanced brings transformative capabilities:
- AI/ML integration - native AI for network optimization
- XR optimization - immersive media support
- Ambient IoT - battery-less IoT devices
- Duplex evolution - SBFD, full duplex
- Network energy saving - green networks
- Enhanced positioning - cm-level accuracy
- NTN evolution - expanded satellite integration
📋 Specifications: TR 21.918 (Rel-18 Description)
AI/ML for RAN
Native AI/ML integration into the radio access network.
AI/ML Use Cases (Rel-18)
| Use Case | Application |
|---|---|
| CSI feedback | AI-enhanced CSI compression |
| Beam management | AI-predicted beam selection |
| Positioning | AI-improved location accuracy |
Framework
┌─────────────────────────────────────────┐
│ AI/ML Framework │
├─────────────────────────────────────────┤
│ ┌─────────┐ ┌─────────┐ ┌─────────┐ │
│ │ Training│ │ Model │ │Inference│ │
│ │ │──│ Transfer│──│ │ │
│ └─────────┘ └─────────┘ └─────────┘ │
│ ↑ ↓ │
│ ┌─────────┐ ┌─────────┐ │
│ │ Data │ │ Output │ │
│ │Collection│ │ Action │ │
│ └─────────┘ └─────────┘ │
└─────────────────────────────────────────┘
Model Types
| Location | Training | Inference |
|---|---|---|
| UE-side | At UE/network | At UE |
| Network-side | At network | At gNB |
| Joint | Collaborative | Split |
Life Cycle Management
- Data collection - measurements, KPIs
- Training - online/offline
- Model validation - performance verification
- Deployment - model transfer
- Inference - real-time execution
- Monitoring - performance tracking
- Update/fallback - model refresh
📋 Specifications: TR 38.843 (AI/ML for NR Study)
XR Support
Extended Reality (VR/AR/MR) optimization for immersive experiences.
XR Requirements
| Parameter | Requirement |
|---|---|
| Data rate | 30-100+ Mbps |
| Latency (MTP) | <20 ms (motion-to-photon) |
| Jitter | <5 ms |
| Frame rate | 60-120 fps |
| Reliability | 99.9% |
XR Traffic Characteristics
| Aspect | Pattern |
|---|---|
| Periodicity | Video frames (8-16 ms) |
| Size variation | I-frames larger than P-frames |
| Bidirectional | DL video + UL pose/input |
| Bursty | Variable bitrate |
Optimizations (Rel-18)
| Feature | Benefit |
|---|---|
| XR awareness | Scheduler knows frame boundaries |
| Capacity enhancement | Multi-slot scheduling |
| Power saving | DRX aligned with frames |
| Jitter reduction | PDU set handling |
PDU Set Handling
Group PDUs belonging to same video frame:
- Joint scheduling decisions
- Priority inheritance
- Deadline-aware treatment
📋 Specifications: TR 38.838 (XR Study)
Ambient IoT
Ultra-low-power devices harvesting energy from environment (battery-less).
Device Types
| Type | Energy Source | Range | Data Rate |
|---|---|---|---|
| Type A | RF harvesting | <10 m | <1 kbps |
| Type B | RF + storage | <50 m | 1-10 kbps |
| Type C | Battery-assisted | >100 m | Higher |
Communication Topology
┌─────────┐ ┌─────────┐ ┌─────────┐
│ Reader │──────│ Ambient │──────│ gNB │
│ │ RF │ IoT │ │ │
└─────────┘ │ Device │ └─────────┘
└─────────┘
Technology Basis
Building on:
- Backscatter communication
- RFID principles
- Energy harvesting
Use Cases
| Application | Example |
|---|---|
| Logistics | Package tracking |
| Retail | Inventory management |
| Healthcare | Medical sensors |
| Smart home | Environmental sensors |
📋 Specifications: TR 38.848 (Ambient IoT Study)
Duplex Evolution
Enhanced spectrum efficiency through advanced duplex modes.
SBFD (Subband Full Duplex)
Simultaneous DL and UL in same carrier using frequency separation:
Frequency
↑
│ ┌───────────────────────────────────┐
│ │ Downlink │
│ ├───────────────────────────────────┤
│ │ Guard │ │
│ ├───────────────┤ │
│ │ Uplink │ │
│ └───────────────┴───────────────────┘
└──────────────────────────────────────→ Time
Cross-Link Interference
| Type | Description | Mitigation |
|---|---|---|
| gNB-to-gNB | DL TX → neighbor RX | Coordination |
| UE-to-UE | UL TX → neighbor RX | Scheduling |
Full Duplex (Study)
- Self-interference cancellation required
- Analog + digital domain cancellation
- >100 dB cancellation needed
📋 Specifications: TR 38.858 (Duplex Evolution Study)
Network Energy Saving
Green network initiatives for sustainability.
Energy Saving Techniques
| Category | Technique |
|---|---|
| Spatial | Cell/beam/antenna switching |
| Temporal | DTX, micro-sleep |
| Frequency | Carrier/BWP switching |
| Power | Adaptive transmission power |
AI/ML for Energy Saving
| Application | Benefit |
|---|---|
| Traffic prediction | Anticipate load changes |
| Sleep scheduling | Optimize wake/sleep patterns |
| Beam management | Reduce active beams |
| Coordination | Multi-cell optimization |
Energy Efficiency KPIs
| KPI | Definition |
|---|---|
| EE | bits/Joule |
| EC | kWh per unit data |
| Network EE | Coverage × Capacity / Power |
📋 Specifications: TR 38.864 (NES Study)
Enhanced Positioning
Sub-meter to cm-level accuracy.
Rel-18 Enhancements
| Feature | Improvement |
|---|---|
| Carrier phase | cm-level accuracy |
| Multi-RTT | Enhanced multilateration |
| Side link | UE-to-UE ranging |
| NR+LTE | Multi-RAT positioning |
Accuracy Targets
| Environment | Rel-17 | Rel-18 Target |
|---|---|---|
| Indoor | <3 m | <0.2 m |
| Outdoor | <10 m | <0.2 m |
| Industrial | <1 m | <0.1 m |
Positioning Methods
| Method | Technique | Accuracy |
|---|---|---|
| DL-TDOA | Downlink time difference | ~10 m |
| Multi-RTT | Round-trip time | ~3 m |
| DL-AoD | Angle of departure | Variable |
| UL-AoA | Angle of arrival | Variable |
| Carrier phase | Phase measurement | ~cm |
📋 Specifications: TS 38.305 (Positioning)
Rel-19/20 Outlook
Rel-19 (2025) Focus Areas
| Area | Description |
|---|---|
| AI/ML Phase 2 | Extended use cases |
| NTN evolution | IoT-NTN, regenerative |
| XR enhancement | Improved QoE |
| Ambient IoT | Normative work |
| Energy saving | Enhanced techniques |
Rel-20 (2026) - Towards 6G
| Topic | Direction |
|---|---|
| Sub-THz | 100+ GHz studies |
| AI-native | AI as fundamental component |
| Sensing | Integrated communication & sensing |
| ISAC | Joint radar/communication |
| Sustainability | Enhanced green networks |
| Security | Post-quantum cryptography |
6G Vision
| Capability | Target |
|---|---|
| Peak rate | 1 Tbps |
| Latency | <0.1 ms |
| Reliability | 99.99999% |
| Positioning | <1 cm |
| Spectrum | Sub-THz, visible light |
| Intelligence | Ubiquitous AI |
📋 Specifications: Watch 3GPP Release planning for updates
Timeline
- 2021 - 5G-Advanced study started
- 2022 - Rel-18 work items approved
- 2024 - Rel-18 frozen (AI/ML, XR, Ambient IoT)
- 2025 - Rel-19 frozen (expected)
- 2026 - Rel-20 frozen (expected)
- 2028+ - 6G standardization expected