3GPP Release 16 - RAN features

3GPP Release 16, finalized in June 2020, represents 5G Phase 2, refining the foundation laid by Release 15. It broadens 5G NR capabilities beyond enhanced mobile broadband (eMBB), addressing industrial automation, ultra-reliable low-latency communication (URLLC), V2X, non-public networks (NPN), and integrated access and backhaul (IAB). The RAN1–RAN5 workgroups each contributed critical enhancements, detailed below with their technical implications, implementation guidance, and use-case mapping. 

RAN1 — Physical Layer Enhancements

Focus: OFDM enhancements, URLLC reliability, positioning, unlicensed spectrum, and MIMO optimization.

1. NR-URLLC Physical Layer Enhancements

• Expanded HARQ design, flexible slot configurations, and symbol-level preemption allow URLLC data to interrupt eMBB transmissions without full TTI scheduling.

• Redundant transmission mechanisms (DCI 0_2/1_2 formats) enhance link reliability.

• Implementation: gNB PHY scheduler dynamically reserves symbols for preemption, adjusting power for URLLC reliability.

• Use case: Factory robotic control requiring <1 ms latency and 99.9999% reliability.

2. Integrated Access and Backhaul (IAB)

• Introduced multi-hop backhaul using NR radio links.

• IAB Nodes act as both access and relay points supporting F1-AP over NR.

• Implementation: IAB-nodes utilize self-backhaul, maintaining synchronization via in-band operations; deployment uses topology auto-discovery.

• Use case: 5G urban densification where fiber is unavailable.

3. MIMO and Mobility Enhancements

• Improved precoding and beam management for FR2 with new CSI-RS modes.

• Codebook enhancements support high-rank transmission and multi-TRP diversity.

• Use case: High-speed train coverage continuity using beam-level mobility.

4. NR in Unlicensed Spectrum (NR-U)

• Enables operation in 5 GHz and 6 GHz bands using Listen-Before-Talk (LBT) coordination.

• Coexists with Wi-Fi 6 through channel occupancy time and contention window adjustments.

• Use case: 5G private networks leveraging shared spectrum for enterprise applications.

5. Positioning and Power Saving

• NR positioning via DL-TDOA, UL-TDOA, and PRS enhancements achieving <1 m accuracy.

• Power saving features like Discontinuous Reception (DRX) optimizations for periodic wakeups.

• Use case: Industrial IoT asset localization in smart factories.

RAN2 — Radio Interface Protocol and Mobility Enhancements

Focus: MAC/RLC/PDCP optimizations, enhanced mobility, and low-latency signaling.

1. Dual Active Protocol Stack (DAPS) Handover

• Maintains source and target links simultaneously, achieving near-zero handover interruption.

• Implementation: UE maintains both RLC entities; PDCP duplication avoids packet loss.

• Use case: URLLC or VoNR continuity during mobility.

2. Enhanced Random Access (2-Step RACH)

• Reduces access latency by combining Msg1 and Msg2, enabling faster access and data transmission.

• Use case: Autonomous vehicle wake-up signaling with rapid uplink data initiation.

3. QoS and SDAP Enhancements

• Added QoS monitoring framework: real-time KPI feedback loops integrated into the MAC layer.

• Supports NR experience assurance through PDB (Packet Delay Budget) tracking.

4. Multi-Radio Dual Connectivity (MR-DC) Enhancement

• Optimized bearer split for Coordinated Multipoint (CoMP) with LTE-NR or NR-NR dual connectivity.

• Use case: Seamless coverage between macro and mmWave small cells.

5. Time-Sensitive Networking (TSN) support

• Introduced precise time distribution between 5G radio and industrial Ethernet.

• Implementation: PDCP integrates with 5G-TSN translator for bounded latency support.

• Use case: Industrial process automation.

RAN3 — Architecture and Interface Evolution

Focus: NG-RAN architecture (CU/DU split), IAB relay configuration, network slicing, and private 5G integration.

1. Enhancements to F1 and E1 Interfaces

• Support for IAB user and control plane signaling between CU and DU.

• Introduced resource partitioning for relay paths via F1-AP coordination.

• Use case: Cloud RAN deploying chainable DU topology over NR IAB links.

2. Non-Public Networks (NPN) Integration

• Defined architecture for Standalone (SNPN) and Public Network Integrated (PNI-NPN) modes.

• Use case: Dedicated enterprise 5G networks with secure local .slice operation.

3. Network Slicing Enhancements

• RAN-controlled selection of Network Slice Instances (NSIs) per UE session.

• Implementation: RRC adapts slice mappings to SDAP filters via 5QI parameters.

4. IAB Control Functions

• IAB Management in RAN3 includes topology adaptation and failure recovery.

• Nodes exchange backhaul status and synchronize timing over NR interfaces.

5. 5G LAN Services

• Provided group-based logical channels for closed user groups.

• Use case: Campus networks where 5G operates as LAN replacement.

RAN4 — RF, Spectrum, and Performance Enhancements

Focus: spectrum allocation, power efficiency, and coexistence frameworks.

1. New Spectrum Bands (FR1 + FR2 Expansion)

• FR1 extended up to 7.125 GHz, FR2 up to 52.6 GHz.

• Implementation: UE RF chains adapt with dynamic tuning and digital predistortion for EVM compliance.

• Use case: Operators launching mid-band (n77/n78/n79) and mmWave (n257/n258) networks.

2. Cross-Link Interference (CLI) and Remote Interference Management (RIM)

• Defined CLI-RSSI and CLI-RSRP measurements with inter-cell UL/DL coordination signaling.

• Use case: Dense small cell deployment reducing inter-gNB interference.

3. Carrier Aggregation and MIMO RF Specifications

• Enhanced tuner management for dual connectivity bands (sub-6 + mmWave).

• RAN4 ensured backward compatibility with Release 15 NR devices.

4. Power Efficiency Standardization

• Introduced sleep control and dynamic EIRP for beam-based transmission.

• Use case: 5G base stations employing advanced envelope tracking to reduce power.

RAN5 — Conformance, Testing, and Validation

Focus: 5G NR UE/base station conformance, OTA testing, and performance validation.

1. IAB and NR-U Test Cases

• Defined test profiles for relay nodes, unlicensed operation, and beam measurement accuracy.

• Use case: Vendor interoperability validation for NR-U and IAB deployment.

2. mmWave OTA Calibration Framework

• Established OTA chamber procedures for validation of mmWave beam tracking and switching.

• Implementation: Includes dynamic beam performance evaluation in 3D radiation pattern.

3. URLLC and QoS Verification

• Introduced conformance KPIs for latency (<1 ms E2E) and reliability (>99.9999%) for industrial-grade UEs.

4. Multi-TRP and Mobility Testing

• Validated simultaneous connectivity scenarios to test make-before-break transition KPIs.

Practical Use Case Mapping Across RAN Groups

Feature	WG	Use Case / Benefit
URLLC PHY Enhancements	RAN1	Real-time robotics, tele-surgery
2-Step RACH	RAN2	Fast wakeup IoT & automotive access
DAPS Handover	RAN2	Seamless VoNR continuity
IAB Relay	RAN1 / RAN3	Wireless backhaul for urban small cells
NR-U	RAN1 / RAN4	Private 5G networks using unlicensed bands
TSN Support	RAN2	Industrial automation, process control
NPN Framework	RAN3	Enterprise private 5G
CLI/RIM	RAN4	Dense small cell coexistence
OTA/mmWave Testing	RAN5	Beam tracking verification

Summary

Release 16 transformed 5G NR from an enhanced mobile broadband platform into a holistic communication ecosystem, enabling industrial-grade reliability, mobility, and automation.

• RAN1 optimized PHY design with URLLC, IAB, and positioning.

• RAN2 refined radio protocols for deterministic networking and low latency.

• RAN3 established a modular architecture for private networks and backhaul.

• RAN4 balanced spectral and power efficiency for dense deployments.

• RAN5 formalized conformance validation for 5G NR and mmWave operations.

In essence, 3GPP Release 16 enabled 5G to evolve beyond connectivity — toward a programmable, reliable, and context-aware industrial infrastructure.

References

1. https://www.3gpp.org/specifications-technologies/releases/release-16

2. https://www.etsi.org/deliver/etsi_ts/138300_138399/138306/16.03.00_60/ts_138306v160300p.pdf

3. https://www.etsi.org/deliver/etsi_ts/138200_138299/138201/16.00.00_60/ts_138201v160000p.pdf

4. TS 38.321        NR; Medium Access Control (MAC) protocol specification   

5. TS 38.322        NR; Radio Link Control (RLC) protocol specification 

6. TS 38.323        NR; Packet Data Convergence Protocol (PDCP) specification  

7. TS 38.331        NR; Radio Resource Control (RRC); Protocol specification