3GPP Release 16 Explained: Expanding 5G from Enhanced Mobile Broadband to Industry-Grade Connectivity

3GPP Release 16, often called 5G Phase 2, completed the initial full 3GPP 5G system and shifted the technology from primarily consumer-focused enhanced mobile broadband (eMBB) toward reliable, low-latency, and flexible support for industrial, automotive, enterprise, and IoT applications.⁠

Timeline, Status, and Relationship to Earlier Releases

3GPP develops mobile standards in parallel “Releases” that freeze a stable set of features for implementation while continuing work on subsequent releases. Release 15 (5G Phase 1) introduced the foundational 5G New Radio (NR) air interface, basic architecture options (non-standalone and standalone), and initial support for the three ITU IMT-2020 pillars: eMBB, ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC).

Release 16 was functionally frozen and completed at the TSG#88e Plenary meetings ending 3 July 2020 (Stage 3, ASN.1, and OpenAPI freezes). It met the requirements for the ITU IMT-2020 “initial full 3GPP 5G system” submission. Official summaries appear in 3GPP Technical Report TR 21.916.⁠

In practice, Release 16 refined coverage, capacity, latency, reliability, power efficiency, mobility, and ease of deployment while adding capabilities tailored to “vertical” industries.

Overarching Themes and Objectives

The dominant theme of Release 16 is making the 5G System (5GS) industry-grade. It strengthens the platform for transportation (including autonomous driving), automated factories, healthcare, public safety, private enterprise networks, and more. Key system-wide directions include:

Completing and hardening URLLC for deterministic performance.
Enabling non-public (private) networks and unlicensed spectrum operation.
Improving radio efficiency and deployment flexibility (especially dense or fiber-scarce environments).
Enhancing positioning, sidelink communications, and IoT support.
Strengthening network slicing, edge computing, and LAN-type services.

Radio work focused heavily on NR while also improving LTE and LTE–NR interworking. End-user bit rates rose through expanded carrier aggregation configurations and 256QAM support in additional scenarios.⁠

Major Technical Feature Areas

Ultra-Reliable Low-Latency Communications (URLLC) and Industrial IoT

Release 15 laid the foundation for low latency with mini-slots and basic reliability mechanisms. Release 16 significantly raised reliability targets (packet error rates down to $10^{-6}$ 10−6, or “six nines”) while preserving stringent latency bounds—critical for factory automation, motion control, and remote operations.⁠

Key enhancements include:

Physical-layer improvements: expanded HARQ designs, flexible slot configurations, symbol-level preemption (allowing URLLC traffic to interrupt eMBB), redundant transmissions, and more robust downlink control information (DCI) formats with configurable sizes.
Multi-TRP (multiple transmission/reception points) and coordinated multi-point (CoMP) techniques for spatial diversity and link reliability.
Support for Time-Sensitive Networking (TSN) integration, precise time synchronization (via gPTP), QoS monitoring, and Ethernet frame transport optimizations.
Core-network support for redundant transmission paths, dynamic packet delay budget handling, and session continuity.

These capabilities enable 5G to act as a TSN bridge in industrial environments.

Vehicle-to-Everything (V2X) and NR Sidelink

Building on LTE-based C-V2X from earlier releases, Release 16 introduced a native NR sidelink optimized for advanced automotive use cases. It supports unicast, groupcast, and broadcast modes with HARQ feedback, higher data rates, lower latency, and distance-based grouping. This underpins platooning, sensor sharing, and remote driving scenarios, operating both in and out of network coverage.⁠

Unlicensed Spectrum (NR-U) and Non-Public Networks (NPN)

NR-U allows 5G NR operation in unlicensed bands (notably 5 GHz and 6 GHz) using listen-before-talk and coexistence mechanisms with Wi-Fi. Combined with explicit architectural support for standalone non-public networks (SNPN) and public-network-integrated NPNs (PNI-NPN), this enables secure, dedicated private 5G deployments for enterprises, campuses, factories, and airports without relying solely on licensed spectrum.⁠

Integrated Access and Backhaul (IAB)

IAB introduces wireless backhaul using the same NR radio technology for both access and relay links. IAB-nodes and IAB-donors support multi-hop topologies, topology adaptation, and resource partitioning. This reduces the need for fiber in dense urban small-cell deployments or temporary coverage scenarios.⁠

Positioning Services

Release 16 established a robust NR positioning framework with techniques such as downlink and uplink time-difference of arrival (TDoA), angle-based methods leveraging massive MIMO beams, and enhanced positioning reference signals. Target accuracies support industrial asset tracking and other location-critical applications (later releases further refined performance).

MIMO, Mobility, Access, and Power-Efficiency Improvements

Enhanced multi-user MIMO, multi-TRP support, improved beam management (especially important for mmWave), and full-power uplink transmission.
Dual Active Protocol Stack (DAPS) handover for reduced interruption time (valuable for voice over NR and URLLC).
2-step random access channel (RACH) procedure that collapses the traditional four-step process, lowering control-plane latency and enabling faster small-data transmission.
UE power-saving features including wake-up signals, refined discontinuous reception (DRX), cross-slot scheduling enhancements, and low-power carrier aggregation control.

Additional radio refinements cover cross-link and remote interference management, expanded carrier aggregation and dual-connectivity combinations, and RF requirements for new spectrum ranges.

Cellular IoT and Related Optimizations

Release 16 improved support for NB-IoT and LTE-MTC over the 5G core, added control-plane and user-plane CIoT optimizations, extended DRX, and other power- and coverage-related enhancements. These keep low-complexity, low-power devices viable within the broader 5G ecosystem.

Other system features include further network-slicing refinements, edge-computing support, LAN-type services (5G as a wireless Ethernet replacement for closed user groups), wireless–wireline convergence, and various northbound API and mission-critical service extensions.

Feature-to-Use-Case Mapping

Feature Area	Primary Working Groups	Representative Use Cases / Benefits
URLLC PHY & protocol enhancements	RAN1, RAN2	Factory robotics, process control, tele-operation
Multi-TRP / CoMP	RAN1	Reliability in blocked or industrial environments
TSN integration	RAN2, System	Deterministic industrial Ethernet replacement
NR Sidelink V2X	RAN1, SA	Platooning, advanced safety, sensor sharing
NR-U + NPN	RAN1, RAN3, SA	Private enterprise/campus 5G networks
IAB	RAN1, RAN3	Fiber-less dense small-cell or temporary deployments
2-step RACH	RAN2	Fast IoT / automotive access and small-data uplink
Positioning	RAN1	Indoor/outdoor industrial asset tracking
DAPS handover & mobility	RAN2	Seamless VoNR and URLLC continuity
Power saving	RAN1, RAN2	Longer battery life for devices and reduced network energy

Broader Impacts and Industry Perspective

Release 16 transformed 5G from a high-speed consumer broadband technology into a versatile platform capable of serving mission-critical and industrial workloads. Reliability, determinism, private-network flexibility, and deployment economics improved substantially. Operators gained tools for densification without proportional fiber investment; enterprises gained standards-based options for on-premise 5G; automotive and manufacturing verticals received purpose-built radio and system features.

Performance gains appear in higher aggregated bandwidths (especially FR1 carrier aggregation), improved spectral efficiency via MIMO and modulation upgrades, lower control-plane latency, and the ability to meet far stricter reliability targets without simply increasing retransmissions (which would violate latency budgets).

Subsequent releases (17 and beyond) have continued the trajectory with further positioning accuracy, reduced-capability (RedCap) devices, non-terrestrial networks, and 5G-Advanced features. Release 16 remains the foundational “Phase 2” specification that many commercial networks and industrial solutions still reference as the baseline for advanced 5G capabilities.

In summary, 3GPP Release 16 completed the initial full 5G system definition while deliberately broadening its addressable market. It delivered the technical tools—higher reliability, flexible spectrum use, wireless backhaul, advanced sidelink, precise positioning, and private-network architectures—needed to move 5G beyond smartphones into factories, vehicles, campuses, and critical infrastructure. For network architects, equipment vendors, and vertical industry planners, it marks the point at which 5G became a genuine multi-industry communications platform rather than primarily an enhanced broadband service.

1) Completing the Initial Full 5G System

Background: IMT-2020 and the Phased 3GPP Approach

The International Telecommunication Union Radiocommunication Sector (ITU-R) defined IMT-2020 as the global framework for fifth-generation mobile systems. It established stringent minimum performance requirements (detailed in ITU-R M.2410 and related reports) covering peak and user-experienced data rates, latency, reliability, connection density, spectral efficiency, mobility, and other metrics. These requirements span three primary usage scenarios:

Enhanced Mobile Broadband (eMBB)
Ultra-Reliable Low-Latency Communications (URLLC)
Massive Machine-Type Communications (mMTC)

3GPP structured its 5G work in phases to meet both commercial deployment needs and the formal IMT-2020 submission timeline. Release 15 (often called 5G Phase 1) delivered the New Radio (NR) air interface, basic system architecture options (non-standalone and standalone), and strong eMBB capabilities, along with initial support for the other two pillars. It enabled early commercial networks but did not yet constitute a fully compliant “initial full 5G system” under the ITU process.

Release 16 was explicitly positioned as 5G Phase 2. Its completion in July 2020 (Stage 3 and ASN.1/OpenAPI freezes at TSG#88e) brought the IMT-2020 submission for an initial full 3GPP 5G system to closure.

The IMT-2020 Submission Process and Release 16’s Contribution

3GPP prepared two independent submissions for ITU evaluation:

SRIT (Set of Radio Interface Technologies): Combining NR with E-UTRA/LTE (including standalone LTE, NB-IoT, eMTC, and LTE-NR dual connectivity).
RIT (Radio Interface Technology): Standalone NR.

Both submissions encompassed features from Releases 15 and 16. The process followed a multi-year timeline that included initial description templates, self-evaluation updates, performance evaluations against the three usage scenarios and defined test environments, and final specification material. An initial submission occurred around late 2017 / 2018, with a final comprehensive submission in mid-2019 that incorporated Release 16 updates alongside Release 15. Independent Evaluation Groups assessed the material; no significant concerns were raised regarding 3GPP’s compliance claims.

Self-evaluation by 3GPP concluded that both the NR-based RIT and the combined SRIT fulfilled all IMT-2020 requirements across eMBB, mMTC, and URLLC scenarios. Formal endorsement by ITU-R followed, with 3GPP 5G (including NB-IoT elements) recognized as meeting the technological standards of IMT-2020.

Release 16 supplied the critical enhancements needed to close remaining performance and functional gaps—most notably in reliability, determinism, industrial applicability, and system completeness—so that the overall package could be declared an initial full system rather than a partial or early-drop technology.

Key Gaps Closed by Release 16

Release 15 provided a solid baseline, especially for high-throughput eMBB. Release 16 addressed areas required for full IMT-2020 compliance and broader system readiness:

URLLC reliability and latency: Enhanced physical-layer mechanisms (including multi-TRP, improved HARQ, preemption, and robust control signaling) and core-network support raised reliability toward the levels demanded by ITU requirements (often cited as 99.999% or higher under strict latency bounds). These were essential for meeting the URLLC performance targets that basic Release 15 capabilities alone did not fully satisfy in all evaluation scenarios.
Support for vertical industries and system versatility: Features enabling Non-Public Networks, Time-Sensitive Networking integration, advanced V2X sidelink, positioning improvements, and LAN-type services expanded the system beyond consumer broadband, aligning with the broader vision of 5G as a multi-industry platform.
Deployment and efficiency foundations: Integrated Access and Backhaul, NR in unlicensed spectrum, mobility enhancements (such as Dual Active Protocol Stack handover), power-saving mechanisms, and refined carrier aggregation / MIMO capabilities improved practical deployability and spectral efficiency.
IoT and continuity elements: Strengthened Cellular IoT support (including NB-IoT and eMTC under the 5G Core) and better LTE–NR interworking ensured the SRIT submission remained robust.

These additions allowed 3GPP to demonstrate comprehensive compliance rather than relying solely on the Phase 1 foundation.

Timeline, Adjustments, and Formal Completion

The original plan targeted Release 16 completion in time to support the final IMT-2020 submission steps. Schedule shifts occurred (including a three-month adjustment agreed in late 2018 and further impacts from the COVID-19 pandemic that moved Stage 3 freeze considerations), yet the ASN.1 and OpenAPI specification freeze was achieved on the adjusted timeline in July 2020. At that point, 3GPP could finalize the specification material submitted to ITU-R for inclusion in the detailed IMT-2020 recommendations (ultimately reflected in Recommendation ITU-R M.2150 and related documents).

This completion marked the transition from “initial 5G” (capable of early commercial eMBB-focused deployments) to a standards-complete system recognized under the global IMT-2020 framework.

Broader Significance

Completing the initial full 5G system via Release 16 had several lasting effects:

It provided regulatory and market certainty that 3GPP 5G fully met the internationally agreed performance benchmarks.
It enabled operators, equipment vendors, and vertical industries to plan deployments with confidence that the technology satisfied the complete set of eMBB, URLLC, and mMTC requirements.
It established a stable baseline upon which later releases (17 and beyond) could add enhancements—such as further positioning accuracy, non-terrestrial networks, and Reduced Capability devices—without re-opening the foundational IMT-2020 compliance question.
It reinforced 3GPP’s role as the primary global standards body delivering interoperable 5G technology.

In short, Release 16 did not invent 5G; it finished the first complete, standards-compliant version. By filling the remaining technical and performance gaps identified against ITU IMT-2020 criteria and finalizing the dual RIT/SRIT submissions, it converted the Phase 1 foundation into an initial full 3GPP 5G system ready for worldwide recognition and multi-industry use. Subsequent evolution has built on this completed base rather than replacing it.

2) Industry-Grade Reliability and Determinism

Why Reliability and Determinism Became Central

Release 15 introduced foundational URLLC tools, including mini-slots, configured grants, and basic low-latency structures, and demonstrated compliance with the baseline IMT-2020 URLLC target of approximately 99.999% reliability within a 1 ms user-plane latency budget for small packets. Industrial use cases, however, demanded stricter performance: reliability on the order of 99.9999% (six nines, or a packet error rate of $10^{-6}$ 10−6) combined with latencies as low as 0.5–1 ms, bounded jitter, and precise time synchronization. Simply increasing retransmissions was insufficient because it would violate latency constraints.⁠

Release 16 therefore treated reliability and determinism as first-class design goals. The objective was to make the 5G System (5GS) suitable for factory automation, process control, electrical power distribution, and other environments where packet loss or variable delay can halt production lines or compromise safety.

Performance Targets and Use-Case Drivers

Key targets associated with Release 16 URLLC and Industrial IoT work included:

Reliability of up to 99.9999% for critical packets under defined channel conditions.
One-way user-plane latency in the 0.5–1 ms range for high-priority traffic.
Support for deterministic (isochronous or time-aware) traffic with tight bounds on latency variation.
Accurate time synchronization (often targeting sub-microsecond accuracy at the air interface in combination with TSN mechanisms).

These targets were driven by prioritized industrial scenarios such as motion control, cooperative robotics, control-to-control communication, and smart-grid differential protection. The work items on physical-layer URLLC enhancements and NR Industrial IoT directly addressed the gap between Release 15 capabilities and these more demanding requirements.

Radio-Layer Mechanisms for Higher Reliability

Several complementary techniques raised link reliability without proportionally increasing latency:

Multi-Transmission/Reception Point (Multi-TRP) and Coordinated Multi-Point (CoMP): A device can transmit to or receive from multiple geographically separated points simultaneously or in a coordinated fashion. Spatial diversity provides redundant communication paths so that blockage or deep fades on one path do not cause packet loss.
Enhanced Hybrid Automatic Repeat Request (HARQ): Support for multiple HARQ-ACK feedbacks within a single slot (sub-slot-based feedback), simultaneous construction of two HARQ-ACK codebooks with different priorities, and faster processing timelines. These reduce the latency of retransmissions when they are still needed.
Packet Data Convergence Protocol (PDCP) duplication: Expansion of duplication options (including combinations of dual connectivity and carrier aggregation) so that the same packet can travel over more than two independent paths, with elimination of duplicates at the receiver.
Preemption and prioritization: Symbol-level or resource-level preemption allows high-priority URLLC traffic to interrupt ongoing eMBB transmissions. Uplink cancellation indicators and power-control enhancements further protect critical uplink traffic from interference by lower-priority users.
Robust control signaling: Improved Physical Downlink Control Channel (PDCCH) monitoring capabilities, new DCI formats with configurable field sizes (to reduce control-channel overhead and improve robustness), and more reliable uplink control channels.
Configured grant and semi-persistent scheduling refinements: Multiple active configurations, flexible periodicities (any integer multiple of a slot up to longer values), and enhanced repetition patterns support deterministic traffic patterns efficiently while maintaining reliability through repetitions when required.

These mechanisms work together: spatial and path diversity handle many channel impairments, while protocol-level prioritization and fast feedback keep residual retransmissions within the latency budget.

Determinism Through TSN Integration and Time-Sensitive Communication

Reliability alone is insufficient for many industrial applications; the system must also deliver packets with predictable timing. Release 16 introduced explicit support for Time-Sensitive Networking integration so that the 5G System can function as a virtual TSN bridge.⁠

Key elements include:

Mapping of TSN streams onto 5G Quality-of-Service flows with appropriate priority and resource allocation.
Support for time-aware scheduling and related TSN functions (such as per-stream filtering and policing) so that the wireless segment appears to the industrial control plane as a standard IEEE 802.1 bridge.
Precise time synchronization distribution (leveraging mechanisms compatible with IEEE 802.1AS / gPTP) across the 5G domain.
Handling of Ethernet frames with header compression and efficient transport to minimize overhead for industrial traffic.

This architecture enables “brownfield” integration: existing TSN-based industrial Ethernet systems can incorporate 5G wireless links without redesigning the higher-layer control applications. Later releases further refined these capabilities, but Release 16 established the foundational bridge model and the associated radio and core-network support.

Core-Network and System-Level Support

Reliability and determinism also required enhancements beyond the radio interface:

Redundant user-plane paths (for example, dual-connectivity-based end-to-end redundancy or dual PDU sessions) so that packets can be duplicated and sent over disjoint routes, with elimination at the receiving end.
QoS monitoring and dynamic handling of packet delay budgets.
Session continuity mechanisms suited to high-reliability services.
Efficient handling of mixed traffic (URLLC + eMBB) on the same device or cell through prioritization and resource isolation.

These system features ensure that the end-to-end path—from device through radio access network and core to the industrial application—can meet the required reliability and timing bounds.

Practical Impact and Limitations

In controlled industrial environments (especially private or non-public networks with favorable radio conditions), Release 16 capabilities enable wireless replacement or augmentation of cabling for many automation tasks. Demonstrations and early deployments have shown sub-millisecond latencies with very high reliability when the full set of features is applied. The combination of multi-TRP diversity, prioritization, TSN bridging, and path redundancy moves 5G from “best-effort with occasional low latency” toward true industrial-grade deterministic performance.

At the same time, achieving the highest targets still depends on careful network planning, spectrum availability, interference management, and deployment density. Not every outdoor or highly mobile scenario will reach six-nines reliability under 0.5 ms latency without additional engineering. Release 16 provided the standardized toolkit; realizing the full potential remains a system-design and implementation challenge.

Summary

Release 16 transformed URLLC from a promising foundation into an industry-capable solution by combining spatial and path diversity, accelerated and prioritized feedback, robust control signaling, flexible deterministic scheduling, and seamless TSN integration. The result is a 5G System able to deliver the reliability (approaching or reaching 99.9999%) and determinism required for motion control, factory automation, and related vertical applications while coexisting with conventional broadband traffic. This focus on industrial-grade performance remains one of the defining themes of 5G Phase 2 and continues to influence subsequent releases and real-world private-network deployments.

3) Expansion to Vertical Industries

Strategic Context: From Consumer Broadband to Multi-Industry Platform

Release 15 delivered a strong foundation optimized primarily for high-capacity, high-speed mobile broadband. While it included initial support for ultra-reliable low-latency communications (URLLC) and massive machine-type communications (mMTC), the overall system was still heavily oriented toward traditional mobile network operators and smartphone-centric services.

Release 16 treated expansion to vertical industries as a core objective. The goal was to make the 5G System (5GS) a versatile, standards-based communications platform that could serve manufacturing, automotive, enterprise, public safety, transportation, and other specialized domains without requiring each industry to invent proprietary solutions. Official summaries of the release describe this trend as increasing the versatility and reliability of the 5GS to make it “industry-grade compatible” for verticals such as autonomous driving, railways, maritime, automated factories, healthcare, and public safety.

This expansion was not incidental; it shaped architecture, radio features, and core-network capabilities so that the same underlying 5G technology could be configured for public mobile networks, private enterprise deployments, or hybrid models.

Primary Vertical Markets Targeted

Release 16 work explicitly addressed or enabled several key verticals:

Manufacturing and Industrial IoT (IIoT) — Factory automation, motion control, process control, cooperative robotics, and deterministic industrial Ethernet replacement.
Automotive and Intelligent Transportation — Advanced cellular vehicle-to-everything (C-V2X) for safety, platooning, sensor sharing, and steps toward higher levels of automation.
Enterprise and Private Networks — Campuses, airports, ports, warehouses, hospitals, and other on-premise or localized deployments requiring security, control, and performance isolation.
Public Safety and Mission-Critical Services — Extensions of existing mission-critical capabilities and broader applicability beyond traditional public-security users.
Other transportation and specialized domains — Railways, maritime (intra-ship, ship-to-shore), and early considerations for non-terrestrial or aerial elements (with fuller support coming later).
Broader IoT and LAN-type services — Closed user groups, campus networking, and efficient support for low-complexity devices within the 5G ecosystem.

These areas were chosen because they offered clear commercial demand, had stringent technical requirements that Release 15 only partially met, and could benefit from standardized rather than proprietary wireless solutions.

Key Technical Enablers for Vertical Expansion

Several Release 16 features were designed or refined specifically to serve these markets:

Vertical Focus	Primary Enabling Features in Release 16	Main Benefit
Industrial automation / IIoT	Enhanced URLLC, TSN integration, multi-TRP, configured grants, PDCP duplication	Deterministic, high-reliability wireless links suitable for control loops
Automotive / C-V2X	NR sidelink (unicast, groupcast, broadcast with HARQ), distance-based grouping	Advanced safety and automation use cases, including out-of-coverage operation
Enterprise / Private networks	Non-Public Networks (SNPN and PNI-NPN), NR in unlicensed spectrum (NR-U)	Secure, dedicated or hybrid private 5G without sole reliance on licensed spectrum or public operators
Dense or fiber-scarce sites	Integrated Access and Backhaul (IAB)	Cost-effective densification and temporary coverage
Positioning-dependent apps	NR positioning enhancements (TDoA, angle-based methods, PRS)	Asset tracking and location services in industrial or indoor environments
Campus / closed groups	5G LAN-type services	Ethernet-like group communication over 5G
Continuity and mixed traffic	Mobility enhancements (e.g., DAPS handover), prioritization mechanisms	Seamless operation for voice, critical data, and broadband on the same network

Additional supporting elements included refinements to network slicing, edge computing hooks, QoS frameworks, and Cellular IoT optimizations so that low-power devices could coexist efficiently with high-performance industrial traffic.

Industrial and Manufacturing Vertical

For factories and process industries, Release 16 combined ultra-high reliability (targeting up to 99.9999% in demanding scenarios), low and bounded latency, precise time synchronization, and native support for Time-Sensitive Networking. The 5G System can act as a virtual TSN bridge, allowing existing industrial Ethernet protocols and control applications to incorporate wireless links with minimal redesign. This enables cable replacement or augmentation for robotic cells, mobile assets, and flexible production lines while maintaining the determinism previously available only over wired connections.

Automotive and Transportation Vertical

Release 16 introduced a native NR-based sidelink optimized for advanced V2X. Building on earlier LTE C-V2X, the NR sidelink supports higher data rates, lower latency, HARQ feedback for reliability, and both groupcast and unicast modes. Distance can be used as a physical-layer dimension for forming multicast groups “on the fly.” These capabilities support platooning, cooperative perception, remote driving assistance, and other use cases that go beyond basic safety messaging, while still functioning in coverage-limited or out-of-coverage situations.

Enterprise and Private Network Vertical

A major architectural advance was formal support for Non-Public Networks. Standalone Non-Public Networks (SNPN) and Public Network Integrated NPNs (PNI-NPN) allow organizations to deploy dedicated 5G infrastructure with strong isolation, local breakout, and customized policies. Combined with NR operation in unlicensed spectrum (NR-U, particularly in 5 GHz and 6 GHz bands with listen-before-talk coexistence), this opened practical paths for private 5G in factories, campuses, logistics hubs, and other enterprise settings without depending exclusively on licensed spectrum or public mobile operators.

Ecosystem and Market Impact

By standardizing these capabilities, Release 16 lowered barriers for vertical industries to adopt cellular technology. Equipment vendors could develop specialized solutions on a common base; operators could offer private-network or network-as-a-service models; and enterprises gained the option of self-managed or hybrid deployments. The release also strengthened the case for 5G in public-safety and specialized transportation domains by extending mission-critical features and improving reliability and coverage tools.

Later releases built on this foundation (further positioning accuracy, Reduced Capability devices, non-terrestrial networks, additional TSN refinements), but Release 16 was the pivotal moment at which 5G’s vertical ambitions became concrete and commercially actionable.

Limitations and Practical Considerations

Full realization of vertical use cases still depends on spectrum availability, radio planning, device ecosystems, and integration with existing operational technology systems. The highest reliability and determinism targets are most readily achieved in controlled private-network environments rather than in wide-area public networks under all conditions. Interoperability testing, certification, and industry-specific profiles remain important for large-scale adoption.

In summary, Release 16 expanded 5G from a primarily consumer-oriented broadband technology into a standards-based platform capable of serving manufacturing, automotive, enterprise, public safety, and related verticals. Through targeted features—enhanced URLLC and TSN for industry, NR sidelink for vehicles, Non-Public Network architectures and unlicensed access for enterprises, and supporting tools such as IAB and positioning—it established the technical and architectural basis for multi-industry 5G. This expansion remains one of the defining contributions of 5G Phase 2.

4) Deployment Flexibility and Economic Efficiency

Strategic Context: Bridging Performance and Practicality

Release 15 established strong radio performance, particularly for enhanced mobile broadband, but real-world deployments quickly highlighted constraints. Fiber availability for backhaul, limited licensed spectrum in some markets, high costs of dense small-cell grids, power consumption of devices and infrastructure, and mobility challenges in mixed environments all limited scale and economic attractiveness—especially for private networks, industrial sites, and urban densification.

Release 16 treated deployment flexibility and economic efficiency as explicit design objectives. The aim was to lower the total cost of ownership, enable more flexible network topologies, and make 5G viable in a wider range of geographic and operational scenarios without sacrificing the performance gains already achieved.

Integrated Access and Backhaul (IAB)

One of the most significant contributions to deployment flexibility is Integrated Access and Backhaul. IAB allows a gNB (or portions of it) to use the same NR radio technology for both access links to user equipment and wireless backhaul links to other network nodes.

Key characteristics include:

Support for in-band and out-of-band backhaul.
Multi-hop topologies with IAB-nodes and IAB-donors.
Topology adaptation, failure recovery, and resource partitioning between access and backhaul traffic.
Integration with the existing F1 interface and overall RAN architecture.

By reducing or eliminating the need for fiber to every small cell, IAB substantially lowers deployment costs and time-to-market in dense urban environments, temporary event coverage, rural or hard-to-reach areas, and industrial campuses where laying fiber is impractical or prohibitively expensive. It enables more organic network densification that can grow with demand.

Spectrum Flexibility: NR in Unlicensed Spectrum (NR-U)

Release 16 standardized NR operation in unlicensed spectrum bands (notably portions of 5 GHz and 6 GHz), incorporating listen-before-talk and other coexistence mechanisms with incumbent systems such as Wi-Fi.

This capability provides several economic and deployment advantages:

Private and enterprise networks can leverage shared spectrum without acquiring expensive licensed holdings.
Operators gain additional capacity options for traffic offload or supplemental coverage.
Hybrid licensed + unlicensed deployments become more practical.
Regulatory and market barriers to private 5G are reduced in many jurisdictions.

Combined with Non-Public Network architectures, NR-U made self-contained or lightly licensed private 5G deployments far more accessible for factories, campuses, logistics hubs, and similar environments.

Non-Public Networks and Architectural Flexibility

Formal support for Standalone Non-Public Networks (SNPN) and Public Network Integrated Non-Public Networks (PNI-NPN) gave enterprises and vertical operators standardized ways to deploy isolated or hybrid networks. These architectures support local traffic breakout, customized security and policy control, and reduced dependence on public mobile operator infrastructure. The result is greater freedom in network design and ownership models, improving both operational control and long-term economics for specialized users.

Mobility, Densification, and Interference Management

Additional features improved the practicality of dense and mobile deployments:

Dual Active Protocol Stack (DAPS) handover and other mobility enhancements reduce interruption times, supporting seamless service continuity for voice over NR and latency-sensitive applications during cell transitions.
Cross-Link Interference (CLI) and Remote Interference Management (RIM) mechanisms help manage interference in dense small-cell and time-division duplex environments, improving spectral efficiency and reliability of densified networks.
Expanded carrier aggregation and dual-connectivity combinations, along with MIMO and beam-management refinements, allow more efficient use of available spectrum and better coverage at the cell edge.
Power-saving features for user equipment (including wake-up signals, refined discontinuous reception, and efficient secondary-cell management) extend battery life and reduce device-side energy costs—important for both consumer and industrial IoT devices.

Collectively, these improvements make high-density and high-mobility deployments more robust and cost-effective to operate.

Power Efficiency and Operational Economics

Beyond radio-access features, Release 16 included refinements aimed at lower energy consumption. Device power-saving techniques reduce battery drain, while network-side considerations (such as more efficient beam management and reference-signal designs that lower peak-to-average power ratios) contribute to more sustainable base-station operation. In large-scale deployments, even modest efficiency gains translate into meaningful reductions in operational expenditure.

Mapping Features to Deployment Scenarios

Challenge	Release 16 Solution	Primary Economic or Flexibility Benefit
Fiber scarcity or high cost	Integrated Access and Backhaul (IAB)	Lower civil-works and backhaul costs; faster densification
Limited licensed spectrum	NR-U (unlicensed operation)	Additional capacity and private-network viability
Need for private/isolated networks	Non-Public Network architectures (SNPN/PNI-NPN)	Greater control, security, and tailored economics
Dense small-cell interference	CLI / RIM, improved beam management	Higher spectral efficiency and reliability in dense grids
Mobility-induced service gaps	DAPS handover and mobility enhancements	Better user experience and support for critical services
Device and network energy use	UE power-saving features, efficient RS design	Lower operational and device lifecycle costs

Broader Impact and Practical Considerations

These capabilities collectively lowered barriers to both public-network densification and private/enterprise 5G. Operators gained tools to expand coverage and capacity more economically; enterprises gained viable options for self-managed or hybrid networks; and the overall ecosystem benefited from greater deployment diversity.

Realizing the full benefits still requires careful radio planning, spectrum coordination (especially for unlicensed and TDD bands), multi-vendor interoperability for IAB, and appropriate security and management frameworks for private networks. Performance in challenging propagation environments or under heavy load continues to depend on implementation quality and site engineering.

In summary, Release 16 made 5G significantly more deployable and economically attractive by introducing wireless backhaul (IAB), unlicensed spectrum operation (NR-U), flexible private-network architectures, improved mobility and interference management, and power-efficiency measures. These advances addressed key practical constraints that limited the scale and commercial viability of earlier 5G deployments, reinforcing the release’s role in transforming 5G into a broadly usable, multi-industry technology platform.

5) Spectral Efficiency, Capacity, and Coverage Enhancements

Context: Continuing the Evolution of Foundational Performance

While Release 16 is widely recognized for enabling industrial and vertical use cases, it also delivered substantial refinements to core NR capabilities. Official summaries note that end-user bit rates increased through expanded carrier aggregation configurations and the addition of 256QAM in additional scenarios. MIMO operation received targeted improvements where Release 15 was identified as deficient in spectral efficiency, transmit-power efficiency, signaling overhead, and multi-point transmission support.

These changes raise average and cell-edge performance, allow more efficient use of available spectrum, and extend practical coverage—benefits that apply to both public mobile broadband networks and private or industrial deployments.

Massive MIMO and Multi-TRP Enhancements

MIMO remains one of the primary levers for spectral efficiency in 5G. Release 16 advanced several aspects:

Enhanced multi-user MIMO (MU-MIMO) and CSI feedback: Improvements to Type II channel-state information (CSI) codebooks reduced uplink feedback overhead through spatial-domain compression while supporting higher ranks (up to rank-4 MIMO per user in relevant configurations) and finer quantization/precoding-matrix-indicator granularity. This enables more accurate multi-user precoding and higher spatial multiplexing gains.
Multi-transmission/reception point (multi-TRP) operation: Devices can communicate with multiple geographically separated transmission points. Non-coherent joint transmission allows different data streams from different points, increasing downlink data rates and spectral efficiency, especially for cell-edge users. The same framework also supports reliability improvements via spatial diversity when the same data is sent over multiple paths.
Multi-beam management refinements: Features such as secondary-cell beam failure recovery, interference-aware beam selection, and reduced overhead improve robustness and efficiency, particularly important in millimeter-wave (FR2) deployments where beam tracking is critical.
Reference-signal improvements: Lower peak-to-average power ratio (PAPR) designs for uplink and downlink reference signals improve power-amplifier efficiency.

Collectively, these MIMO advances increase both peak and average spectral efficiency while improving link reliability and cell-edge performance.

Carrier Aggregation, Modulation, and Bandwidth Expansions

Capacity gains also come from the ability to aggregate more spectrum and use higher-order modulation more widely:

In Frequency Range 1 (FR1, sub-7 GHz), the maximum aggregated bandwidth for intra-band contiguous carrier aggregation rose from 200 MHz in Release 15 to 300 MHz. Additional support for intra-band non-contiguous combinations and inter-band dual connectivity within FR1 further expands usable bandwidth.
In Frequency Range 2 (FR2, mmWave), frequency-separation classes increased (for example, up to 2.4 GHz for certain intra-band non-contiguous cases), enabling larger total aggregated bandwidths and more component carriers. Downlink 256QAM support was added for FR2, raising peak spectral efficiency in good channel conditions.
The overall number of supported band combinations grew substantially, giving operators and private-network planners far greater flexibility in combining mid-band, high-band, and (where available) low-band spectrum.

These changes directly translate into higher peak and average user throughputs and greater system capacity under the same spectrum holdings.

Uplink Coverage and Power Efficiency

Coverage, especially uplink coverage at the cell edge, received explicit attention. Release 16 introduced full-power uplink transmission for all MIMO-capable devices. Previously, certain multi-antenna uplink configurations required power backoff; the new support allows devices to transmit at their full rated power across relevant codebook-based and non-codebook-based modes. This improves uplink cell-edge data rates and extends the practical coverage radius for services that rely on strong uplink performance (for example, industrial sensors, video uplink, or high-reliability control traffic).

Related power-efficiency improvements (lower-PAPR reference signals and refined beam/power-control mechanisms) further help both coverage and device/network energy consumption.

Interference Management for Dense Deployments

In dense TDD small-cell networks, cross-link interference (CLI) between neighboring cells and remote interference can degrade capacity. Release 16 standardized measurement and mitigation frameworks for CLI and Remote Interference Management (RIM). By enabling better coordination and interference awareness, these tools help preserve spectral efficiency and capacity as networks densify—an important complement to the MIMO and carrier-aggregation gains.

Summary of Performance Levers

Dimension	Primary Release 16 Mechanisms	Expected Impact
Spectral efficiency	Enhanced Type II CSI / MU-MIMO, multi-TRP NCJT, 256QAM in FR2, beam refinements	Higher bits/s/Hz per cell and per user
System capacity	Expanded CA bandwidths and combinations (FR1 to 300 MHz contiguous, larger FR2 aggregation), more CCs	Higher aggregate throughput and support for denser traffic
Coverage (especially UL)	Full-power uplink for MIMO devices, improved RS and beam management	Better cell-edge rates and extended practical range
Dense-network efficiency	CLI / RIM frameworks	Maintained capacity as small cells proliferate

Practical Considerations and Limitations

The magnitude of gains depends on deployment conditions: spectrum availability, channel quality, number of antenna elements, backhaul quality for multi-TRP, and traffic mix. In favorable mid-band or mmWave scenarios with advanced MIMO, the combination of higher-rank MU-MIMO, multi-TRP, and larger aggregated bandwidths can produce substantial throughput increases. In challenging coverage-limited or interference-heavy environments, the uplink full-power and interference-management features become particularly valuable.

These enhancements remain backward-compatible with Release 15 devices and networks while unlocking higher performance for Release 16-capable equipment. Later releases continued the trajectory (further MIMO evolution, even larger bandwidths, and AI-assisted techniques), but Release 16 established important intermediate steps in spectral efficiency, capacity, and coverage that benefited both public broadband and the emerging vertical/private-network use cases.

In summary, Release 16 strengthened the foundational radio performance of 5G through refined massive MIMO and multi-TRP operation, expanded carrier aggregation and higher-order modulation, full-power uplink transmission, and interference-management tools. These improvements raise spectral efficiency and capacity while extending practical coverage, ensuring that the system remains competitive for high-throughput services even as it expands into industrial and enterprise domains.

6) Ultra-Reliable Low-Latency Communications (URLLC) and Industrial IoT

Context: From Foundational URLLC to Industrial-Grade Performance

Release 15 introduced the basic building blocks for URLLC, including mini-slot (non-slot-based) transmissions, configured grants for low-latency uplink access, and mechanisms aimed at meeting the IMT-2020 baseline of approximately 99.999% reliability within a 1 ms user-plane latency budget for small packets. These features proved that NR could support low-latency services, but many industrial applications required still higher reliability, tighter latency bounds, deterministic behavior, and seamless integration with existing industrial Ethernet systems.

Release 16 treated URLLC and IIoT as priority work areas. Two closely related efforts—physical-layer enhancements for NR URLLC and support for NR Industrial Internet of Things—drove improvements that raised reliability targets toward 99.9999% (a packet error rate of $10^{-6}$ 10−6) while preserving or further reducing latency (often targeting the 0.5–1 ms range). The objective was to make 5G suitable for closed-loop control, cooperative robotics, process automation, and other scenarios where packet loss or variable delay can disrupt production.

Performance Targets for Industrial Use Cases

Key targets associated with Release 16 URLLC/IIoT work included:

Reliability of up to 99.9999% under defined conditions for critical packets.
One-way user-plane latency in the range of 0.5–1 ms for high-priority traffic.
Support for deterministic (isochronous or time-aware) traffic with bounded jitter.
Precise time synchronization compatible with industrial requirements (often sub-microsecond accuracy when combined with TSN mechanisms).
Efficient coexistence of URLLC and enhanced mobile broadband (eMBB) traffic on the same cell or device.

These targets were shaped by prioritized industrial scenarios such as motion control, control-to-control communication, factory automation, and electrical power distribution.

Physical-Layer and Protocol Enhancements

Release 16 introduced a set of complementary techniques to raise reliability without simply increasing the number of retransmissions (which would violate latency budgets):

Multi-Transmission/Reception Point (Multi-TRP) and Coordinated Multi-Point (CoMP): A device can exchange data with multiple geographically separated points. Spatial diversity provides redundant paths so that temporary blockage or deep fading on one link does not cause packet failure. Both single-DCI and multi-DCI non-coherent joint transmission options were supported.
Enhanced Hybrid Automatic Repeat Request (HARQ): Sub-slot-based HARQ-ACK feedback enables multiple feedback opportunities within a single slot. Simultaneous construction of two HARQ-ACK codebooks with different priorities allows differentiated treatment of critical versus best-effort traffic. Faster processing timelines further reduce retransmission latency.
Preemption and prioritization: Symbol-level or resource-level preemption lets high-priority URLLC traffic interrupt ongoing eMBB transmissions. Uplink cancellation indicators and enhanced power control protect critical uplink traffic from interference by lower-priority users.
Robust control signaling: Improved PDCCH monitoring capabilities, new DCI formats with configurable field sizes (to reduce overhead and improve robustness), and more reliable uplink control channels.
Configured grant and semi-persistent scheduling refinements: Multiple active configurations, flexible periodicities (any integer multiple of a slot), and enhanced repetition patterns support deterministic traffic more efficiently while retaining the option of repetitions for reliability.
Packet Data Convergence Protocol (PDCP) duplication: Expansion of duplication options (including combinations of dual connectivity and carrier aggregation) allows the same packet to travel over more than two independent paths, with duplicate elimination at the receiver.

These mechanisms operate together: multi-TRP and path diversity handle many channel impairments, while prioritization, fast feedback, and controlled repetitions keep residual recovery actions within the latency budget.

System-Level and Core-Network Support

Reliability and determinism also required enhancements beyond the radio interface:

Redundant user-plane paths (for example, dual-connectivity-based end-to-end redundancy or dual PDU sessions) so packets can be duplicated and sent over disjoint routes.
QoS monitoring, dynamic division of the packet delay budget, and session-continuity mechanisms suited to high-reliability services.
Efficient handling of mixed traffic (URLLC + eMBB) through prioritization and resource isolation on the same UE or cell.

Time-Sensitive Networking (TSN) Integration for Determinism

A flagship Release 16 capability for Industrial IoT is the integration of the 5G System with IEEE Time-Sensitive Networking. The 5GS can function as a virtual TSN bridge, appearing to the industrial control plane as a standard IEEE 802.1 Ethernet bridge.

Key elements include:

Mapping of TSN streams onto 5G QoS flows with appropriate priority and resource allocation.
Support for time-aware scheduling and related TSN functions (such as per-stream filtering and policing).
Distribution of precise time synchronization (compatible with IEEE 802.1AS / gPTP) across the 5G domain.
Efficient transport of Ethernet frames, including header compression.

This architecture enables “brownfield” integration: existing TSN-based industrial Ethernet systems can incorporate 5G wireless segments without redesigning higher-layer control applications. It provides the deterministic timing and bounded latency required for many closed-loop industrial processes.

Mapping Features to Industrial Benefits

Capability	Release 16 Mechanism(s)	Primary Industrial Benefit
Ultra-high reliability	Multi-TRP, PDCP duplication, robust HARQ/control	Tolerance to blockage and interference in factories
Low and bounded latency	Mini-slot inheritance + enhanced HARQ, preemption, configured grants	Support for fast control loops (motion, robotics)
Deterministic / isochronous traffic	TSN bridge model, time-aware scheduling, precise sync	Compatibility with industrial Ethernet and PLCs
Mixed traffic coexistence	Prioritization, preemption, dual codebooks	URLLC and eMBB on the same infrastructure
Path and spatial diversity	Multi-TRP, multi-connectivity redundancy	Resilience without excessive retransmissions

Practical Impact and Limitations

In controlled private-network or non-public network environments with favorable radio conditions, Release 16 URLLC and IIoT features enable wireless replacement or augmentation of cabling for many automation tasks. Early demonstrations and deployments have shown that sub-millisecond latencies with very high reliability are achievable when the full feature set is applied. The combination of multi-TRP diversity, prioritization, TSN bridging, and path redundancy moves 5G from occasional low-latency capability toward true industrial-grade performance.

Achieving the most stringent targets still depends on careful radio planning, spectrum choice, interference management, device capabilities, and end-to-end system design. Outdoor or highly mobile scenarios, or deployments with significant blockage, may require additional engineering to approach six-nines reliability under the tightest latency bounds. Later releases further refined these capabilities (additional TSN enhancements, improved positioning, Reduced Capability devices, etc.), but Release 16 established the essential toolkit.

In summary, Release 16 transformed URLLC from a promising foundation into an industrial-capable solution. Through multi-TRP operation, enhanced HARQ and prioritization, robust control signaling, flexible deterministic scheduling, path redundancy, and native TSN integration, it delivered the reliability (approaching or reaching 99.9999%), low latency, and determinism required for motion control, factory automation, and related Industrial IoT applications. This remains one of the defining technical contributions of 5G Phase 2 and continues to underpin private 5G deployments in manufacturing and process industries.

7) Vehicle-to-Everything (V2X) and NR Sidelink

Context: Evolution from LTE C-V2X to NR Sidelink

Earlier 3GPP releases (particularly Release 14) introduced LTE-based C-V2X sidelink primarily to support basic safety applications. These included vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure (V2I) broadcast of fundamental safety messages such as cooperative awareness messages. The LTE sidelink was designed for relatively simple, periodic broadcast traffic with moderate reliability and latency requirements.

Release 16 marked a significant step forward by specifying a dedicated NR-based sidelink. This new sidelink was designed from the outset to meet the more demanding requirements of advanced V2X use cases while leveraging the flexibility, higher spectral efficiency, and lower latency potential of 5G NR. It supports operation both in network coverage and out of coverage, and it coexists with the evolving LTE V2X ecosystem.

Key Capabilities of the NR Sidelink

The NR sidelink in Release 16 introduced several important advances over its LTE predecessor:

Communication modes: Support for unicast, groupcast (multicast), and broadcast. Unicast and groupcast enable more efficient and reliable targeted exchanges rather than pure broadcast.
HARQ feedback: Hybrid Automatic Repeat Request feedback improves reliability for unicast and groupcast transmissions by allowing acknowledgments and selective retransmissions.
Higher data rates and larger payloads: The NR physical layer supports higher modulation and coding schemes and more flexible resource allocation, enabling richer sensor data sharing and higher-volume exchanges.
Lower latency: Shorter transmission time intervals and optimized procedures help meet the tighter latency needs of advanced applications.
Distance-based grouping: Physical-layer mechanisms can use distance or proximity as a dimension for forming multicast groups “on the fly,” which is particularly useful for localized cooperative maneuvers.
Resource allocation flexibility: Resources can be scheduled by the network (gNB) when the vehicle is in coverage, or selected autonomously by the UE in a contention-based manner when out of coverage or for latency-sensitive scenarios.
Coexistence and evolution: The design supports coexistence with LTE V2X and provides a foundation for further enhancements in later releases.

These features collectively enable more sophisticated, higher-performance direct communications between vehicles, roadside units, and other road users.

Supported Advanced V2X Use Cases

Release 16 NR sidelink targets use cases that go beyond basic safety messaging:

Platooning: Coordinated movement of vehicle groups with tight spacing, requiring reliable, low-latency exchange of control and status information among platoon members.
Advanced driving and cooperative perception: Sharing of sensor data (for example, camera, radar, or lidar information) to extend situational awareness beyond line-of-sight or individual vehicle sensor range.
Remote driving / tele-operation support: High-reliability, low-latency links that can assist or enable remote control in certain scenarios.
Extended sensors and vehicle-to-network (V2N) augmentation: When network coverage is available, sidelink can complement Uu (network) links; when coverage is absent, sidelink maintains critical local communications.
Vehicle-to-pedestrian and vulnerable road user protection: Enhanced groupcast and proximity-aware mechanisms improve warnings and coordination with non-vehicle road users.

In coverage areas, advanced V2X services can also leverage the URLLC capabilities of the NR Uu interface together with edge computing to achieve low end-to-end latencies.

Architectural and Operational Aspects

The NR sidelink operates within the broader 5G System framework:

In-coverage operation: The gNB can schedule sidelink resources, providing centralized coordination, interference management, and quality-of-service control.
Out-of-coverage or partial-coverage operation: UEs autonomously select resources according to predefined configurations and sensing procedures, ensuring continuity of safety-critical communications even when network infrastructure is unavailable.
Integration with the 5G Core and application layer: Architecture enhancements support advanced V2X service handling, including quality-of-service differentiation, and application-layer frameworks for service discovery and management.
Security and privacy considerations: Mechanisms address authentication, integrity, and privacy requirements appropriate for vehicular environments.

The design allows gradual deployment: basic safety can continue on LTE V2X while advanced services migrate to or are introduced on NR sidelink as device penetration grows.

Benefits and Practical Considerations

The NR sidelink delivers several advantages for the automotive ecosystem:

Higher reliability and efficiency for targeted (unicast/groupcast) communications compared with pure broadcast.
Support for richer data exchanges needed for cooperative automated driving functions.
Flexibility to operate with or without network coverage.
A standards-based path that can scale across manufacturers and regions.

Realizing the full potential depends on spectrum availability (often in ITS bands or licensed spectrum), device penetration, accurate positioning, and careful management of interference in dense traffic scenarios. Regulatory frameworks, certification, and interoperability testing remain important for large-scale adoption. Later 3GPP releases continued to refine sidelink capabilities (including further enhancements for public safety and additional use cases), building on the Release 16 foundation.

Summary

Release 16 introduced a native NR sidelink that significantly expanded Cellular V2X beyond the basic safety-oriented LTE sidelink of earlier releases. By adding unicast and groupcast modes with HARQ feedback, higher data rates, lower latency, distance-based grouping, and flexible resource allocation (network-scheduled or autonomous), it enabled advanced use cases such as platooning, cooperative perception, and richer sensor sharing. The sidelink can operate in or out of network coverage and integrates with the broader 5G System, providing a robust, standards-based foundation for the next generation of connected and automated vehicle applications. This capability remains one of the key vertical-industry contributions of 5G Phase 2.

8) Enabling Private and Enterprise Networks through NPN Architectures and Unlicensed Spectrum Access

Context: The Need for Private 5G

Public mobile networks optimized for wide-area consumer services often cannot fully meet the isolation, security, local control, customized performance, and data-sovereignty requirements of enterprises, factories, campuses, ports, airports, and other specialized environments. Prior to Release 16, private cellular deployments were possible but lacked comprehensive standardized support for identification, selection, access control, and seamless integration with the 5G System. Spectrum acquisition also presented a barrier in many markets.

Release 16 formally introduced Non-Public Networks into the 5G specifications and completed a global framework for NR in unlicensed spectrum. Together these capabilities made standards-based private 5G far more practical and economically viable.

Non-Public Network (NPN) Architectures

Release 16 defined two primary NPN deployment models:

Standalone Non-Public Network (SNPN) An SNPN is operated independently and does not rely on network functions provided by a public land mobile network (PLMN). It is identified by a combination of a PLMN ID and a Network Identifier (NID). Key characteristics include:

Independent network selection and reselection procedures for SNPN-enabled UEs.
Broadcast of SNPN identities in system information (SIB).
Dedicated access control and mobility support within the SNPN.
Ability to operate with its own credentials and security framework (with clarifications and extensions to the 5G key hierarchy for authentication methods).
Optional connectivity to public networks (for example, for voice or wider internet access) via controlled gateways or firewalls.

SNPNs give enterprises full operational control and strong isolation, making them suitable for highly secure or performance-critical environments such as factories or government facilities.

Public Network Integrated Non-Public Network (PNI-NPN) A PNI-NPN is made available through a PLMN, typically by means of dedicated Data Network Names (DNNs), one or more network slice instances allocated to the NPN, or both. Access can be further restricted using Closed Access Groups (CAGs):

CAG identities identify groups of subscribers permitted to access specific cells.
Cells can broadcast CAG information so that unauthorized UEs are prevented from camping or accessing those cells.
Security largely reuses the underlying PLMN security framework, with additional options such as secondary or slice-specific authentication.

PNI-NPNs allow mobile operators to offer private-network services as a managed offering while leveraging existing infrastructure, spectrum, and operational expertise. They also support hybrid models in which public and private services coexist with controlled isolation.

Both models include mechanisms for network discovery, selection, access control, and mobility. System information broadcasts NPN-related parameters (up to a defined number of SNPNs or PNI-NPNs per cell), and RAN procedures support cell selection/reselection and connected-mode mobility appropriate to each model.

NR in Unlicensed Spectrum (NR-U)

Complementing the NPN architectures, Release 16 standardized NR operation in unlicensed spectrum bands (primarily portions of the 5 GHz and 6 GHz ranges). Key aspects include:

Listen-Before-Talk (LBT) and coexistence mechanisms designed so that NR-U does not impact deployed Wi-Fi services more severely than an additional Wi-Fi network would.
Support for both anchored operation (NR-U secondary cells paired with a licensed or shared-spectrum primary cell) and standalone NR-U (operation solely in unlicensed spectrum, connected to a 5G Core).
Channel access, scheduling, HARQ, mobility, and initial-access procedures adapted to the unlicensed environment while reusing NR design principles where possible.
Bandwidth capabilities that support meaningful capacity (for example, substantial downlink bandwidths in the unlicensed bands).

NR-U is especially valuable for private networks because it reduces or eliminates dependence on licensed spectrum holdings. Enterprises can deploy private 5G using readily available shared spectrum, while operators can use it for capacity expansion or private-network offerings. Standalone NR-U combined with an SNPN architecture enables fully self-contained private networks without licensed spectrum.

Combined Value for Enterprise and Private Deployments

The pairing of NPN architectures with NR-U (and, where available, local or shared licensed spectrum) creates flexible deployment options:

Deployment Goal	Enabling Features	Typical Benefits
Full isolation and control	SNPN + optional standalone NR-U	Data stays on-premise; independent management
Operator-managed private service	PNI-NPN (slices, dedicated DNNs, CAG)	Leverages operator infrastructure and expertise
Spectrum flexibility	NR-U (anchored or standalone)	Lower barrier to entry; capacity expansion
Industrial performance	NPN + URLLC/TSN features (from other Rel-16 work)	Deterministic, high-reliability local networks
Hybrid public–private use	PNI-NPN with controlled public network access	Seamless fallback or selective public services

These capabilities support a wide range of enterprise scenarios: manufacturing campuses, logistics hubs, hospitals, universities, airports, ports, and energy facilities. They also align with the broader Release 16 emphasis on vertical industries by providing the architectural and spectrum tools needed for localized, high-performance 5G.

Practical Considerations and Limitations

Successful private-network deployments still require attention to spectrum regulation (availability and rules for unlicensed or local licensed bands vary by country), radio planning, security hardening, device ecosystem readiness, and integration with existing IT/OT systems. Interference management in unlicensed bands and multi-vendor interoperability for NPN features are ongoing practical concerns. Later releases refined NPN management, onboarding, and related capabilities, but Release 16 established the foundational standardized frameworks.

In summary, Release 16 enabled private and enterprise 5G networks by formalizing Non-Public Network architectures—Standalone NPNs identified by PLMN ID + NID and Public Network Integrated NPNs using slices, dedicated DNNs, and Closed Access Groups—and by completing a global solution for NR operation in unlicensed spectrum with fair coexistence mechanisms. Together these features provide the isolation, control, spectrum flexibility, and standards-based interoperability required for a wide range of enterprise and industrial deployments, marking a major expansion of 5G beyond traditional public mobile broadband.

9) Integrated Access and Backhaul (IAB)

Context and Motivation

5G deployments, particularly in urban environments, industrial campuses, or temporary coverage scenarios, often require dense networks of small cells to deliver capacity and coverage. Traditional fiber backhaul to every site is costly, time-consuming, and sometimes impractical due to right-of-way issues, civil works, or physical constraints. Release 16 introduced IAB to enable wireless backhaul using NR itself, reducing or eliminating the need for wired connections to many nodes while reusing the existing 5G radio and protocol stack.

IAB builds on earlier relay concepts but is designed specifically for NR, supporting multi-hop topologies, dynamic topology adaptation, and efficient sharing of radio resources between access and backhaul traffic.

Architectural Components

The IAB architecture defines two primary node types:

IAB-donor: A gNB (or gNB-Central Unit) that provides the interface to the core network and serves as the root of the wireless backhaul topology. It has a wired (or otherwise non-IAB) connection to the 5G Core and manages the overall IAB network.
IAB-node: A relay node that provides both NR access to user equipment (UEs) and wireless backhaul connectivity toward the IAB-donor (directly or via other IAB-nodes). An IAB-node consists of a Mobile Termination (MT) function for the backhaul link and a Distributed Unit (DU) function for the access links to UEs and downstream IAB-nodes.

This split allows the IAB-node to appear as a normal gNB-DU to UEs while using NR for its own backhaul. The architecture reuses the F1 interface (between Central Unit and Distributed Unit) over the wireless backhaul, with adaptations for the multi-hop wireless environment.

Key Technical Features

Release 16 IAB includes several important capabilities:

In-band and out-of-band operation: Backhaul and access can share the same frequency band (in-band) or use separate bands (out-of-band). In-band operation maximizes spectrum reuse but requires careful resource partitioning and interference management.
Multi-hop support: Traffic can traverse multiple IAB-nodes between a UE and the IAB-donor, enabling flexible topology extension without fiber to every site.
Topology adaptation and failure recovery: The network can dynamically reconfigure routes, add or remove nodes, and recover from backhaul link failures.
Resource partitioning and coordination: Mechanisms allow efficient sharing of time, frequency, and spatial resources between access links (to UEs) and backhaul links (between nodes). This includes semi-static and more dynamic approaches to avoid self-interference in in-band deployments.
Synchronization and timing: Support for aligning timing across the IAB topology so that access and backhaul transmissions remain coordinated.
Integration with existing RAN protocols: IAB leverages NR physical-layer designs, beam management (important for mmWave), and higher-layer protocols with necessary extensions for multi-hop and wireless F1 transport.

These features enable both simple single-hop relays and more complex multi-hop meshes or trees.

Benefits for Deployment and Economics

IAB delivers several practical advantages:

Reduced fiber dependency: Significantly lowers the cost and time required to densify networks, especially in urban small-cell grids, industrial sites, or temporary deployments (events, emergency coverage).
Faster time-to-market: Wireless backhaul allows rapid addition of capacity or coverage without waiting for civil works.
Spectrum and infrastructure efficiency: Reuses NR spectrum and radio hardware for both access and backhaul.
Flexibility: Supports gradual densification—operators can start with fiber-fed donors and extend coverage wirelessly as needed.
Applicability across scenarios: Useful for public mobile networks, private/enterprise 5G (especially when combined with Non-Public Network architectures), and industrial campuses where running fiber is difficult.

When combined with other Release 16 features such as NR-U (unlicensed spectrum) or enhanced MIMO/beam management, IAB further improves the economics and practicality of dense or localized 5G deployments.

Operational Considerations and Limitations

While powerful, IAB introduces trade-offs that must be managed:

Capacity overhead: Backhaul traffic consumes radio resources that could otherwise serve UEs; multi-hop topologies amplify this effect. Careful dimensioning and resource partitioning are required.
Latency and reliability: Each hop adds latency and potential points of failure. For ultra-reliable low-latency applications, hop count and link quality must be tightly controlled.
Interference management: In-band deployments require sophisticated coordination to prevent the IAB-node’s own transmissions from interfering with each other or with neighboring cells.
Synchronization and mobility: Maintaining tight timing and handling topology changes or node mobility (if any) add complexity.
Implementation maturity: Multi-vendor interoperability, advanced topology management, and performance optimization continue to evolve beyond the initial Release 16 specifications.

Later releases refined IAB (for example, with additional enhancements to topology management, duplexing, and performance), but Release 16 established the foundational architecture and procedures.

Summary

Integrated Access and Backhaul in 3GPP Release 16 enables 5G nodes to use the same NR radio technology for both user access and wireless backhaul. By defining IAB-donors and IAB-nodes, supporting multi-hop topologies, resource partitioning, topology adaptation, and both in-band and out-of-band operation, IAB substantially reduces dependence on fiber for network densification. It improves the economic and practical feasibility of dense urban small-cell deployments, industrial private networks, and temporary coverage scenarios. While capacity overhead, latency accumulation, and interference management remain important engineering considerations, IAB stands as one of the key deployment-flexibility contributions of 5G Phase 2 and continues to influence real-world 5G rollouts.

10) Positioning Services

Context and Motivation

Accurate device location is essential for emergency services (regulatory requirements), commercial applications (navigation, asset tracking, location-based services), and industrial use cases (factory automation, logistics, indoor tracking). LTE positioning methods such as Observed Time Difference of Arrival (OTDOA) and Enhanced Cell-ID provided useful but limited accuracy. 5G NR offered new opportunities through wider bandwidths, massive MIMO beamforming, operation in both FR1 and FR2, and a flexible architecture.

Release 16 defined the core radio signals, measurements, procedures, and network functions needed to support a range of accuracy and latency levels. Later releases built on this foundation with further accuracy improvements, support for reduced-capability devices, carrier-phase methods, and sidelink positioning, but Release 16 created the essential baseline.

System Architecture

Positioning in the 5G System centers on the Location Management Function (LMF) in the 5G Core. The LMF coordinates positioning procedures, collects measurements, and computes or assists in computing location estimates. Key interfaces and protocols include:

LTE Positioning Protocol (LPP) between the LMF and the UE (extended for NR).
NR Positioning Protocol A (NRPPa) between the LMF and NG-RAN nodes (gNBs).
Support for UE-based, UE-assisted (LMF-based), and NG-RAN node-assisted positioning modes.
Ability to combine multiple methods (hybrid positioning) and to incorporate non-RAT measurements such as GNSS, barometric pressure, WLAN, or sensors.

This architecture supports both regulatory emergency-call positioning and more demanding commercial or industrial scenarios.

Positioning Reference Signals

Release 16 introduced dedicated signals optimized for positioning:

Downlink Positioning Reference Signals (DL-PRS): Configurable comb patterns, beamforming support, and resource sets that enable precise time-of-arrival and received-power measurements from multiple Transmission Reception Points (TRPs).
Uplink Sounding Reference Signals (SRS) for positioning: Configured for accurate uplink measurements at multiple TRPs.

These signals, together with existing SSBs and CSI-RS where appropriate, form the basis for the RAT-dependent methods.

Supported Positioning Methods

Release 16 standardized a comprehensive set of RAT-dependent techniques:

Method	Primary Measurements	Typical Operation Mode	Key Strengths
DL-TDOA	Downlink Reference Signal Time Difference (RSTD), optional PRS-RSRP	UE-based or UE-assisted	Good accuracy with synchronized network; widely applicable
UL-TDOA	Uplink Relative Time of Arrival (RTOA), optional SRS-RSRP	NG-RAN assisted	Leverages network-side processing
Multi-RTT	UE Rx-Tx and gNB Rx-Tx time differences, optional RSRP	UE-assisted / NG-RAN assisted	Robust to network synchronization errors
DL-AoD	PRS-RSRP across beams	UE-based or UE-assisted	Benefits from massive MIMO beam information
UL-AoA	Angle of Arrival (azimuth and zenith)	NG-RAN assisted	Strong in mmWave / multi-antenna deployments
NR Enhanced Cell-ID	Enhanced cell identity plus additional measurements (RSRP, etc.)	UE-assisted / NG-RAN assisted	Low complexity baseline or hybrid component

These methods can be used individually or in hybrid combinations. Angle-based techniques particularly benefit from the beamforming capabilities of NR, while time-based methods exploit wider bandwidths for finer time resolution.

Performance Targets

Release 16 defined indicative targets that guided the design:

Commercial use cases (examples): Horizontal accuracy < 3 m (indoor) or < 10 m (outdoor) for 80% of UEs; vertical accuracy < 3 m for 80% of UEs; end-to-end latency on the order of < 1 s in relevant scenarios.
Regulatory / emergency use cases: More relaxed requirements (typically tens of meters horizontally) with support for availability, reliability, and reasonable time-to-fix.

Evaluations in representative 3GPP scenarios showed that 90-percentile accuracies ranging from a few meters down to a few decimeters were achievable depending on the deployment (indoor hotspot vs. outdoor), bandwidth, number of TRPs, line-of-sight conditions, and method combination. Actual field performance depends on network density, synchronization quality, multipath environment, and implementation.

Benefits and Use Cases

The Release 16 positioning framework supports:

Regulatory emergency services with improved accuracy and reliability over LTE.
Commercial location-based services and navigation.
Industrial and enterprise applications such as indoor asset tracking, worker safety, and logistics within private or non-public networks.
Hybrid operation with GNSS for seamless indoor–outdoor transitions.

Because the same 5G infrastructure can deliver both high-speed connectivity and accurate positioning, operators and enterprises gain additional value from their deployments.

Practical Considerations and Limitations

Achieving the higher-end accuracy targets generally requires good geometry (multiple visible TRPs), sufficient bandwidth, reasonable line-of-sight or manageable multipath, and proper network synchronization (especially for pure TDOA methods). Multi-RTT offers greater robustness to synchronization errors. Dense indoor deployments with many TRPs and wide bandwidths yield the best results, while sparse outdoor or heavily non-line-of-sight environments are more challenging. Device capabilities, power consumption for frequent measurements, and privacy considerations also influence real-world use.

Later releases enhanced accuracy (including centimeter-level potential in some scenarios), added support for reduced-capability devices, carrier-phase measurements, bandwidth aggregation for positioning, and sidelink-based positioning. Release 16, however, remains the foundational specification that made native high-performance 5G positioning a standardized reality.

In summary, 3GPP Release 16 established comprehensive positioning services for 5G NR by defining a flexible architecture centered on the Location Management Function, introducing dedicated downlink PRS and uplink SRS for positioning, and standardizing a suite of time-based and angle-based methods (DL-TDOA, UL-TDOA, Multi-RTT, DL-AoD, UL-AoA, and NR E-CID). These capabilities meet regulatory needs while enabling commercial and industrial use cases with meter-level (and in favorable conditions sub-meter) accuracy, laying the groundwork for the continued evolution of 5G positioning.

11) Enhanced multi-user MIMO, multi-TRP support, improved beam management

Context: Advancing Foundational MIMO and Beam Performance

Release 15 introduced massive MIMO and basic beam management as core NR capabilities. However, practical deployments revealed opportunities for higher spatial multiplexing efficiency, better multi-point coordination, more robust beam handling (especially under blockage or mobility in mmWave), and improved uplink power utilization. Release 16 targeted these areas to deliver higher average and cell-edge throughputs, greater link reliability, and more efficient use of antenna resources across both FR1 and FR2.

Enhanced Multi-User MIMO

Release 16 refined MU-MIMO operation to support higher spectral efficiency with more users and higher ranks:

Improvements to Type II CSI feedback reduced uplink reporting overhead through spatial-domain compression techniques while enabling finer quantization and precoding-matrix-indicator granularity.
Support for higher-rank transmissions (including rank-4 MIMO per user in relevant configurations) increased the number of spatial layers that can be multiplexed.
These changes allow the gNB to perform more accurate multi-user precoding, packing more simultaneous data streams into the same time-frequency resources with reduced inter-user interference.

The net result is improved system capacity and average spectral efficiency, particularly in dense urban or indoor hotspot scenarios where many users can be served on the same resources.

Multi-TRP Support

Multi-TRP operation allows a UE to communicate with multiple geographically separated transmission/reception points. Release 16 standardized both capacity-oriented and reliability-oriented modes:

Non-coherent joint transmission (NCJT): Different data streams (or layers) can be sent from different TRPs, increasing downlink data rates and spectral efficiency—especially beneficial for cell-edge users who can aggregate spatial resources from multiple points.
Spatial diversity / repetition modes: The same data can be transmitted from multiple TRPs, providing robustness against blockage or deep fades. This is particularly valuable for ultra-reliable services and mmWave deployments where links can be intermittently obstructed.
Both single-DCI and multi-DCI scheduling options were supported, along with mechanisms to handle ideal and non-ideal backhaul between TRPs.

Multi-TRP therefore serves dual purposes: boosting capacity through spatial multiplexing across points and improving reliability through path diversity. It also complements coordinated multi-point (CoMP) concepts and integrates with the broader reliability enhancements of Release 16.

Improved Beam Management

Beam management is critical in NR, especially in FR2 (mmWave) where directional beams are essential for overcoming high path loss. Release 16 introduced several practical refinements:

Secondary-cell beam failure recovery procedures allow faster recovery when a beam fails on a secondary cell without disrupting the primary connection.
Interference-aware beam selection helps the network and UE choose beams that minimize interference while maintaining link quality.
Overhead reduction techniques make beam measurement, reporting, and switching more efficient.
Better support for multi-beam operation aligns with multi-TRP deployments and improves robustness under mobility or environmental changes.

These enhancements reduce latency in beam recovery, improve link stability, and lower the signaling cost of maintaining high-quality beams—directly translating into better user experience and higher effective capacity in mmWave networks.

Full-Power Uplink Transmission

Uplink coverage at the cell edge has historically been a limiting factor, particularly for multi-antenna UEs. In earlier configurations, certain codebook-based or multi-layer uplink transmissions required power backoff to meet emission or power-amplifier constraints. Release 16 introduced support for full-power uplink transmission across MIMO-capable devices:

UEs can transmit at their maximum rated power even when using multiple antenna ports or specific precoding configurations.
Related improvements in reference-signal design (lower peak-to-average power ratio) further aid power-amplifier efficiency.

The primary benefit is extended uplink coverage and higher cell-edge uplink data rates. This is valuable for both conventional mobile broadband (better uplink video, cloud services, etc.) and industrial or IoT scenarios that rely on strong uplink performance.

Combined Impact

These four areas work synergistically:

Feature	Primary Benefit	Key Deployment Value
Enhanced MU-MIMO	Higher spectral efficiency & capacity	More users served with higher throughput
Multi-TRP	Capacity (NCJT) + reliability (diversity)	Cell-edge performance & URLLC robustness
Improved beam management	Robustness & efficiency in FR2	Stable mmWave links under mobility/blockage
Full-power uplink	Extended UL coverage	Better cell-edge rates & IoT/industrial uplink

Together they raise average and cell-edge performance, improve reliability for critical services, and make dense or mmWave deployments more practical. The enhancements remain backward-compatible with Release 15 devices while unlocking higher performance for Release 16-capable equipment.

Practical Considerations

Realized gains depend on antenna configuration, channel conditions, network density, backhaul quality (for multi-TRP), and traffic mix. Advanced CSI feedback and multi-TRP coordination increase computational and signaling demands on both the network and devices. In mmWave, beam management improvements are especially important but still require careful site planning to manage blockage. Full-power uplink benefits are most noticeable for power-limited cell-edge users.

Later releases continued MIMO evolution (further codebook enhancements, more advanced multi-TRP, AI-assisted techniques, etc.), but Release 16 delivered critical intermediate steps that strengthened the core radio performance of 5G.

In summary, Release 16 enhanced multi-user MIMO for higher spatial efficiency, standardized multi-TRP operation for both capacity and reliability, refined beam management for robust mmWave performance, and enabled full-power uplink transmission to improve cell-edge coverage. These features collectively advance the spectral efficiency, capacity, reliability, and coverage foundations of 5G NR, benefiting both public mobile broadband and the emerging industrial and enterprise use cases of 5G Phase 2.

12) Dual Active Protocol Stack (DAPS) handover

Context: The Challenge of Handover Interruption

In traditional break-before-make handovers (used in earlier 5G and LTE systems), the UE releases the connection to the source cell before fully establishing the connection to the target cell. This creates a brief interruption period during which no user-plane data can be transferred. While acceptable for many best-effort services, the interruption can degrade voice quality (audible gaps or freezes in VoNR) and is problematic for industrial or mission-critical applications that require continuous connectivity.

Release 16 addressed this limitation with DAPS handover, a make-before-break approach that keeps both radio links active during the transition.

How DAPS Handover Works

In a DAPS handover the UE:

Continues to receive and transmit data on the source cell while simultaneously establishing and activating the target cell connection.
Maintains separate RLC entities for the source and target legs.
Uses PDCP duplication or closely coordinated PDCP operation so that packets can be sent or received over either (or both) links during the handover window.
Performs the random-access procedure toward the target cell without immediately releasing the source link.
Only releases the source cell after the target cell is fully operational and the network confirms the successful completion of the handover.

This dual-active period allows user-plane traffic (including voice packets) to continue flowing with minimal or near-zero interruption. Once the target link is stable, the source link is cleanly released.

Key Technical Elements

Simultaneous source and target protocol stacks: The UE operates dual RLC entities and associated lower-layer configurations during the handover.
PDCP-level coordination: Packet Data Convergence Protocol handles sequencing, duplication (where configured), and reordering so that the higher layers experience a continuous data flow.
Reduced interruption time: Compared with conventional handovers, the break in user-plane connectivity is dramatically shortened—often to a few milliseconds or less under good conditions.
Applicability: Primarily defined for intra-NR handovers; it can be applied in both standalone and appropriate dual-connectivity scenarios.
Network control: The gNB (source and target) coordinates the procedure, including resource allocation on both cells and the timing of source-link release.

Benefits

DAPS handover delivers several practical advantages:

Improved VoNR quality: Near-seamless voice continuity reduces or eliminates audible glitches during cell transitions, which is critical for mobile voice services over 5G.
Support for URLLC and industrial applications: Services that cannot tolerate even short interruptions benefit from the continuous connectivity window.
Better user experience in mobility scenarios: High-speed trains, dense urban environments, and other cases with frequent handovers see smoother performance.
Complement to other Release 16 mobility features: Works alongside enhancements such as conditional handover and improved measurement reporting to create a more robust overall mobility framework.

Practical Considerations and Limitations

While powerful, DAPS handover introduces additional complexity:

The UE must support simultaneous transmission and reception (or rapid switching) on source and target cells, which has implications for RF design, power consumption, and processing.
Both source and target cells must allocate resources during the dual-active period, temporarily increasing network load.
Performance gains depend on radio conditions; deep fades or high interference on either link can still affect the outcome.
Not all handovers necessarily use DAPS—network configuration and UE capability determine when it is applied.

Later releases continued to refine mobility procedures, but DAPS remains a foundational technique for low-interruption handovers in 5G.

Summary

Dual Active Protocol Stack (DAPS) handover, introduced in 3GPP Release 16, enables a UE to maintain active protocol stacks and radio links toward both the source and target cells during a handover. By keeping user-plane data flowing over the source link while the target link is established, and by coordinating PDCP and RLC entities, it achieves a make-before-break transition with significantly reduced interruption time. This capability is particularly important for Voice over NR continuity and for latency- or reliability-sensitive industrial applications, making it one of the key mobility enhancements of 5G Phase 2.

13) UE Power-Saving Features

Context: Why Power Saving Became a Priority

5G NR offers higher data rates and lower latency than previous generations, but these capabilities can increase power draw if not carefully managed. Always-on monitoring of wide bandwidths, multiple carriers, high-order MIMO, and frequent control-channel checks drain batteries—especially problematic for always-connected IoT sensors, smartphones under heavy use, and devices operating in power-limited industrial environments. Release 16 introduced a coordinated set of techniques that allow the network and UE to reduce active time, lower monitoring overhead, and dynamically scale radio resources according to traffic needs.

Key Power-Saving Mechanisms

Wake-Up Signal (WUS)

A low-power, narrowband control signal that informs the UE whether it needs to wake up for a subsequent DRX on-duration or can remain in a deeper sleep state. By checking a simple indication instead of fully decoding the PDCCH in every DRX cycle, the UE avoids unnecessary receiver activity and saves significant energy during periods of low or no traffic.

Enhanced Cross-Slot Scheduling and Bandwidth-Part (BWP) Operation

Release 16 adds explicit minimum scheduling-offset parameters and improved support for BWP switching. These allow the UE more time to prepare for data reception or transmission and enable faster, lower-overhead transitions between narrow and wide bandwidth parts. The UE can spend more time on power-efficient narrow BWPs and only expand bandwidth when high throughput is required.

Efficient Carrier-Aggregation and Secondary-Cell Management

Secondary cells can be activated and deactivated more efficiently under primary-cell control. Low-power carrier-aggregation control reduces the energy cost of maintaining multiple component carriers. In addition, carriers can be grouped into power-mode sets with different DRX configurations—for example, shorter active times on high-frequency (mmWave) carriers versus longer cycles on sub-7 GHz carriers—allowing the UE to optimize sleep patterns per frequency range.

Adaptive MIMO Layer Reduction

The UE can dynamically reduce the number of active transmit or receive antenna chains (for example, from 4×4 to 2×2 MIMO). Turning off unused RF chains and associated baseband processing yields measurable power savings when full spatial multiplexing is not needed.

Device-Assisted Power Saving

The UE can signal preferred power-saving parameters to the network, such as preferred DRX cycles, maximum number of carriers, or maximum bandwidth. This feedback allows the network to configure the UE in a way that better matches the device’s battery state, traffic pattern, and capability, rather than applying a one-size-fits-all configuration.

Supporting Framework

Release 16 also standardized power-consumption models and evaluation methodologies so that vendors and operators can consistently assess the impact of these features. These tools help quantify gains under different traffic and mobility scenarios.

Benefits Across Device Types

Smartphones and consumer devices: Longer battery life under mixed traffic, especially when background apps generate only occasional data.
Industrial and IoT devices: Extended operational lifetime for sensors and actuators that must remain reachable but transmit infrequently.
mmWave-capable UEs: Ability to keep high-frequency carriers in a more aggressive sleep state while maintaining a reliable sub-7 GHz anchor.
Overall network efficiency: Reduced uplink control signaling and more predictable UE behavior can also lower network energy use.

Practical Considerations

Power-saving gains depend on traffic patterns, network configuration, and UE implementation. Aggressive DRX or frequent secondary-cell deactivation can increase latency for the first packet after a sleep period; networks must balance energy savings against quality-of-service requirements. Wake-up signal reliability and coverage are important, particularly at the cell edge. Device-assisted reporting adds a small signaling overhead but generally improves long-term efficiency.

Later releases continued to refine power-saving techniques (further enhancements to WUS, extended DRX, and additional low-power states), yet the Release 16 feature set established the core toolkit still widely used in commercial 5G networks.

Summary

3GPP Release 16 introduced a comprehensive suite of UE power-saving features centered on the wake-up signal, enhanced cross-slot scheduling and BWP operation, efficient secondary-cell and carrier-aggregation management, adaptive MIMO layer reduction, and device-assisted configuration. These mechanisms allow devices to spend more time in low-power states, scale radio resources dynamically, and communicate power preferences to the network. The result is meaningfully improved battery life for smartphones, industrial IoT terminals, and other 5G devices without sacrificing the connectivity and performance expected from NR—making power efficiency one of the practical, user-visible contributions of 5G Phase 2.

14) Cellular IoT and Related Optimizations

Context: Bridging LTE-Era IoT and the 5G System

NB-IoT and LTE-M (enhanced Machine-Type Communication) were developed in earlier 3GPP releases (starting from Release 13) as optimized LTE-based solutions for massive IoT. They deliver excellent coverage, very low device cost and power consumption, and support for massive connection densities. Release 15 began the transition toward the 5G Core (5GC), but comprehensive CIoT support remained limited.

Release 16 formalized “Cellular IoT support and evolution for the 5G System,” bringing a set of features into the 5GC that parallel the earlier EPC optimizations for CIoT. The goal was to allow NB-IoT and LTE-M devices to connect to the 5G Core, benefit from 5G system capabilities (such as improved network slicing and service-based architecture), and continue to operate with the extreme power efficiency required by battery-powered sensors and meters.

Key Architectural and System Enhancements

Release 16 enables NB-IoT and LTE-M UEs to access the 5G Core (using LTE radio as the baseline in many cases). Important aspects include:

Support for connection of Cat-NB (NB-IoT) and Cat-M (LTE-M) devices to the 5GC.
Unified Access Control (UAC) applicable to these devices.
Limited but practical support for 5G concepts: a maximum of two PDU sessions mapped to default data radio bearers in typical configurations; RRC_INACTIVE is supported for LTE-M and partially constrained for NB-IoT.
Coexistence studies confirming that standalone NB-IoT can operate alongside NR without significant issues.

These changes allow operators to migrate IoT traffic toward the 5G Core while protecting existing device investments.

Control-Plane and User-Plane CIoT 5GS Optimizations

Two complementary optimization paths were specified for efficient small-data transfer:

Control Plane CIoT 5GS Optimization

User data (IP, Ethernet, unstructured, or SMS) is transported over the control plane via the Access and Mobility Management Function (AMF). Optional header compression further reduces overhead. This path is ideal for very infrequent, small payloads because it avoids the need to establish a full user-plane path.

User Plane CIoT 5GS Optimization

Data is carried over the user plane with signaling optimizations that minimize the overhead of connection establishment and release. This is useful when slightly larger or more frequent data transfers occur.

Both optimizations, together with related procedures such as Mobile-Originated Early Data Transmission (MO-EDT) in the 5GS context, significantly reduce signaling load and air-interface activity—directly translating into longer battery life and higher system capacity for massive IoT deployments.

Power-Saving and Coverage-Related Enhancements

Release 16 further extended the already strong power-saving capabilities of Cellular IoT:

Extended Discontinuous Reception (eDRX) in RRC_IDLE with very long cycles—up to approximately 44 minutes for eMTC and up to nearly 3 hours for NB-IoT.
Support for longer DRX cycles (up to 10.24 seconds) in CM-CONNECTED with RRC_INACTIVE where applicable.
Enhancements to the Mobile Initiated Connection Only (MICO) mode originally introduced in Release 15.
Additional NB-IoT improvements in transmission efficiency, UE power consumption, scheduling, latency, network management tools, and coexistence with NR.
Parallel MTC enhancements for LTE that improve efficiency and performance in high-speed or challenging scenarios.

These mechanisms allow devices to remain reachable for network-initiated traffic while spending the vast majority of time in deep sleep, supporting multi-year battery operation on small cells or coin batteries.

Additional NB-IoT and MTC Refinements

Beyond core 5GC connectivity, Release 16 included targeted radio and protocol improvements:

Downlink and uplink transmission efficiency gains.
Scheduling enhancements that better match the sporadic traffic patterns of IoT devices.
Improved tools for network management and self-organizing network (SON) functions.
Better support for mixed deployments where NB-IoT or LTE-M cells coexist with NR.

Collectively these refinements keep the LTE-based IoT technologies competitive and future-proof even as the broader network evolves to 5G.

Benefits and Positioning within 5G

The Release 16 CIoT features deliver several practical advantages:

Continuity for the large existing base of NB-IoT and LTE-M devices as operators deploy 5G Core.
Ability to leverage 5G system capabilities (slicing, improved security, unified management) for IoT traffic.
Maintained or improved power efficiency and coverage that remain unmatched by full NR devices for the most constrained sensors.
Higher connection density and lower signaling overhead, supporting the mMTC pillar of 5G.

It is worth noting that later releases introduced Reduced Capability (RedCap) NR devices as a mid-tier option between full NR and classic LPWA technologies. Release 16, however, focused on ensuring that the proven NB-IoT and LTE-M ecosystems could fully participate in the 5G System.

Practical Considerations

Operators must manage the transition carefully—supporting dual connectivity to EPC and 5GC during migration, ensuring proper dimensioning of control-plane resources when many devices use CP optimization, and configuring eDRX and paging parameters to balance reachability against battery life. Device certification and interworking testing remain important given the constrained capabilities of these UEs (for example, limited support for certain 5G features such as full network slicing or high-bandwidth services).

Summary

3GPP Release 16 advanced Cellular IoT by enabling NB-IoT and LTE-M devices to connect to the 5G Core and by introducing Control Plane and User Plane CIoT 5GS optimizations, extended DRX cycles, MICO enhancements, and further radio-level efficiency improvements. These features preserve the low-power, deep-coverage, and low-cost characteristics that define massive IoT while allowing the devices to benefit from the modern 5G System architecture. As a result, Cellular IoT remains a vital and fully supported component of the overall 5G ecosystem, ensuring continuity for the enormous installed base of sensors, meters, and trackers as networks evolve.

15) Enhancements for User Equipment (UE) in 3GPP Release 16

Context: Evolving Device Capabilities for 5G Phase 2

Release 15 established the basic NR UE framework. Release 16 refined that foundation to address practical limitations in battery life, handover interruption, uplink coverage, multi-antenna operation, and support for new vertical services. The result is a more capable and power-efficient UE that can fully exploit the system features introduced for URLLC, Industrial IoT, V2X, Non-Public Networks, and high-precision positioning.

Power-Saving Enhancements

Battery life is a critical concern for smartphones and especially for IoT devices. Release 16 introduced several coordinated mechanisms:

Wake-Up Signal (WUS): A low-power indication that tells the UE whether it needs to wake for a DRX on-duration, allowing longer deep-sleep periods.
Enhanced cross-slot scheduling and Bandwidth Part (BWP) operation: Explicit minimum scheduling offsets and faster BWP switching let the UE remain longer on narrow, power-efficient BWPs.
Efficient secondary-cell management: Faster and lower-overhead activation/deactivation of secondary carriers, plus the ability to configure different DRX cycles per carrier group (for example, more aggressive sleep on mmWave carriers).
Adaptive MIMO layer reduction: The UE can dynamically turn off transmit/receive chains (e.g., drop from 4×4 to 2×2) when full spatial multiplexing is unnecessary.
Device-assisted power saving: The UE can report preferred power-saving parameters (DRX cycle, maximum number of carriers, maximum bandwidth) so the network can tailor configurations to the device’s state and traffic pattern.

These features significantly extend battery life under typical mixed-traffic conditions without sacrificing reachability.

Mobility and Access Procedure Improvements

Dual Active Protocol Stack (DAPS) handover: The UE maintains simultaneous protocol stacks and radio links to both source and target cells during handover (make-before-break). Separate RLC entities and PDCP coordination keep user-plane data flowing, dramatically reducing interruption time—especially valuable for Voice over NR and latency-sensitive applications.
2-step Random Access Channel (RACH): Collapses the traditional four-step procedure into two steps, lowering control-plane latency and enabling faster small-data transmission or rapid resume from inactive states. Beneficial for IoT devices and automotive use cases that need quick uplink access.

MIMO, Coverage, and Beam-Related UE Capabilities

Enhanced multi-user MIMO support: Improved Type II CSI feedback with reduced overhead and support for higher ranks enables more efficient spatial multiplexing.
Multi-TRP operation: The UE can receive (and in some configurations transmit) from multiple geographically separated points, improving both data rates (via non-coherent joint transmission) and reliability (via spatial diversity).
Improved beam management: Secondary-cell beam failure recovery, interference-aware beam selection, and reduced measurement/reporting overhead make mmWave links more robust under mobility or blockage.
Full-power uplink transmission: MIMO-capable UEs can transmit at their maximum rated power across relevant antenna configurations, extending uplink cell-edge coverage and improving uplink performance for industrial sensors or high-quality uplink video.

Support for Vertical and Specialized Use Cases

Release 16 UEs gained capabilities that unlock new applications:

NR sidelink for V2X: Support for unicast, groupcast, and broadcast modes with HARQ feedback, higher data rates, and distance-based grouping—enabling advanced automotive features such as platooning and cooperative perception.
Non-Public Network (NPN) access: Ability to discover, select, and access Standalone NPNs (identified by PLMN ID + NID) and Public Network Integrated NPNs (using CAG), supporting private enterprise and industrial networks.
NR-U operation: Capability to operate in unlicensed spectrum (5 GHz / 6 GHz) with listen-before-talk, either as a secondary cell or in standalone mode—important for private-network deployments.
Industrial IoT / URLLC features: Support for multi-TRP, enhanced HARQ, configured grants with flexible periodicities, PDCP duplication, and TSN-related timing, allowing devices to participate in deterministic factory networks.
Cellular IoT optimizations: NB-IoT and LTE-M devices can connect to the 5G Core with Control-Plane and User-Plane CIoT optimizations plus extended DRX, preserving multi-year battery life while migrating to the modern core.

Positioning Capabilities

UEs support a rich set of measurements for high-precision positioning:

Downlink PRS-based measurements (RSTD, PRS-RSRP) for DL-TDOA and DL-AoD.
Uplink SRS-based measurements for UL-TDOA, UL-AoA, and Multi-RTT.
Reporting of these measurements to the Location Management Function (LMF) in UE-assisted or UE-based modes.

These enable meter-level (and in favorable conditions better) accuracy for emergency services, asset tracking, and industrial location applications.

Capability Signaling and Other Optimizations

Release 16 refined UE radio capability signaling to reduce overhead and improve efficiency when reporting the expanded set of features. Additional improvements cover coexistence with LTE, refined measurement procedures, and support for the broader set of carrier aggregation and dual-connectivity combinations introduced in the release.

Summary of Key UE Enhancements

Category	Main Features	Primary Benefit
Power saving	WUS, enhanced BWP/DRX, adaptive MIMO, device assistance	Longer battery life
Mobility & access	DAPS handover, 2-step RACH	Near-zero interruption, faster access
MIMO & coverage	Enhanced CSI, multi-TRP, beam management, full-power UL	Higher capacity, better cell-edge performance
Vertical support	NR sidelink, NPN access, NR-U, URLLC/IIoT features	Automotive, private networks, industrial use
Positioning	DL/UL TDOA, Multi-RTT, AoA/AoD measurements	Accurate location services
Cellular IoT	5GC connectivity + CP/UP optimizations, eDRX	Efficient massive IoT under 5G Core

Practical Impact

These UE enhancements make Release 16 devices more power-efficient, more robust in mobility and coverage-limited scenarios, and ready for the industrial, automotive, and enterprise use cases that define 5G Phase 2. Realized gains depend on network configuration, spectrum, and implementation quality, but the standardized toolkit gives device vendors and operators clear levers to optimize performance and battery life.

In summary, 3GPP Release 16 substantially advanced UE capabilities across power efficiency, seamless mobility, multi-antenna and multi-point operation, vertical-service support, and positioning. The result is a more versatile and efficient 5G device platform that fully complements the system-level innovations of the release.