In the first part of this blog series looking at 5G QoS control mechanisms we presented a general view of the subject to understand the key principals involved. This time, we’ll look in more detail about how the mechanisms relate to 3GPP standards.

That’s a subject that needs to be understood because 5G Quality of Service (QoS) mechanisms are deeply embedded in 3rd Generation Partnership Project (3GPP) standards and, specifically, in the releases dedicated to 5G technologies, such as Release 15, 16, and beyond. In fact, 3GPP has established a comprehensive QoS framework in 5G, which sets the foundation for how QoS is managed, prioritised, and enforced across the network.

With all that in mind, let’s consider which 3GPP standards relate to 5G QoS mechanisms.

Standardised QoS Flows and 5QI

We referenced and explained QoS flows in the last blog and the concept of QoS flows is defined in 3GPP Technical Specification (TS) 23.501. As we said, QoS flows are fundamental to the 5G QoS model with each flow associated with a 5G QoS Identifier (5QI). Here, 3GPP specifies a list of standardised 5QI values, each of which corresponds to specific service requirements. The values define parameters such as priority, packet delay budget, and packet error rate, and this helps allocate resources according to the service type.

The standardised approach represented here is what enables different vendors and operators to achieve interoperability by mapping specific applications to QoS profiles consistently across networks.

Network Slicing

3GPP has standardised network slicing in TS 23.501 and TS 28.530 in order to ensure that specific QoS requirements are met within isolated virtual networks, which we know more familiarly as slices. In these cases, each slice can have its own QoS configuration, allowing the 5G network to cater to a wide range of differing use cases — from high-reliability applications to those with high throughput or low latency needs — at the same time.

3GPP’s specifications define how network resources are partitioned and how each slice’s QoS is enforced end-to-end. This is what enables unique performance levels for different industry applications.

Policy Control and QoS Management

3GPP TS 23.503 outlines the Policy Control Function (PCF) in 5G, which centrally manages QoS policies based on user subscription, network conditions, and specific application needs. In these scenarios, the PCF coordinates with the Session Management Function (SMF) to set up and enforce QoS rules during session establishment. By managing policies centrally, the PCF can dynamically adapt QoS parameters in real-time as conditions or service requirements change.

Session and Service Continuity (SSC Modes)

3GPP defines three Session and Service Continuity (SSC) modes in TS 23.501, and these determine how sessions and QoS are maintained during mobility events, such as switching between cells or network slices.

• SSC Mode 1 guarantees service continuity without session interruption, suitable for high-reliability applications.
• SSC Mode 2 and 3 provide alternative handling for cases where session re-establishment or modifications can be tolerated, offering flexibility in QoS handling as users move.

QoS Differentiation and Multi-Access Edge Computing (MEC) Integration

The 3GPP provides guidelines for Multi-Access Edge Computing (MEC) integration, so edge nodes can provide localised, low-latency services while managing QoS requirements closer to the user. This enables the 5G network to meet ultra-low latency requirements in applications such as autonomous driving or remote healthcare by offloading traffic to edge servers. This localised QoS control allows real-time traffic management and priority assignment within the 5G QoS framework.

Radio Access Network (RAN) QoS Capabilities

TS 38.300 defines the New Radio (NR) interface, which includes QoS mechanisms specifically for the 5G RAN. NR introduces support for ultra-reliable low-latency communication (URLLC) and advanced radio resource management. Features like Dynamic Spectrum Sharing, Massive MIMO, and beamforming are standardised to improve network efficiency and ensure QoS at the radio layer. This enables 5G networks to meet the stringent requirements of real-time applications, such as factory automation and V2X (vehicle-to-everything) communications.

End-to-End QoS Management

3GPP technical reports (one example is TR 23.700-60) discuss end-to-end QoS management principles in 5G, outlining how QoS is maintained across the core network, transport network, and radio access network. The standard addresses the challenges of multi-domain QoS management, ensuring that QoS parameters are consistently enforced across network elements and that user data packets meet the desired performance requirements from end to end.

Summary

In summary, it’s 3GPP standards that provide the unified framework that’s vital for QoS management across different network layers and functions to deliver. They define the requisite clear, interoperable mechanisms like QoS flows, 5QI values, and network slicing that enables operators to deliver consistent QoS for diverse applications and use cases. 3GPP standards also ensure that 5G networks are flexible and adaptable, allowing them to meet the fast changing and evolving demands of industries such as healthcare, manufacturing, and automotive.

About Emblasoft

Emblasoft is a global provider of Service Enablement, Active Monitoring, Load and Functional Test solutions for, 5G, VoLTE, 4G, 3G and IMS infrastructure. With Emblasoft’s solutions, operators and equipment vendors can obtain and deliver new products and services that push the boundaries of technology.

If you’d like to further discuss testing variable Quality of Service and learn more about Emblasoft, please get in touch.