The promise of delivering highly specific and differentiated services with 5G SA depends on Quality of Service control mechanisms. In this new blog series, we’ll explain why it’s critical to understand the mechanisms and how they’re related to 3GPP standards. Read on.

In this new blog series, we’re going to take a close look at 5G QoS control mechanisms. Where this subject is concerned, there are many details with which most of us need to familiarise ourselves, for one example, being aware of the very specific procedures for requesting and setting the appropriate QoS level for a given session or service (or slice).

In this first blog we’ll start with a more general view of the subject in order to understand the key mechanisms and principals involved in 5G QoS. Next time, we’ll look into how those mechanisms relate to 3GPP standards.

So, as a starting point, we know that in 5G networks, Quality of Service (QoS) mechanisms are central to meeting the varied requirements that range across many significantly different use cases. These run from high-speed mobile broadband to ultra-reliable, low-latency communication for critical applications. Indeed, it could be argued that the success of 5G SA investments depends on ensuring that differentiated services and applications can be delivered – which requires fine-grained, dynamic QoS control.

In this context, 5G itself introduces several innovations that address the corresponding QoS needs in ways that are more advanced and flexible than in previous network generations.

5G QoS mechanisms and principals

Let’s look at those – the key mechanisms and principals involved – in detail.

QoS Flow-Based Architecture

In 5G networks, Quality of Service is managed at the level of “QoS flows”. Each flow corresponds to a specific application or service requirement. Each, therefore, has an associated QoS profile that specifies requirements like latency, reliability, and throughput. The 5G system itself maintains these profiles and adjusts them dynamically as conditions or service requirements change.

Standardised QoS Identifiers (5QI)

The QoS flows are identified by a 5QI (5G QoS Identifier), a standardised tag that maps to predefined service characteristics. This system ensures that different services (for example, video streaming, remote surgery, or driverless cars) receive the network resources necessary to meet their performance requirements. Furthermore, 5QI classes define aspects like default delay bounds, packet error rates, and priority levels.

Network Slicing

Network slicing, as we know, is what allows a single physical network to support multiple virtual networks (slices), each of which is tailored for different types of services. A slice for a critical IoT application, for example, could prioritise low-latency, high-reliability communication, while a different slice might emphasise high throughput for consumer video streaming. Network slicing is managed end-to-end, enabling specific QoS parameters for each slice, which is critical in sectors such as manufacturing, transportation, and healthcare.

Dynamic Resource Allocation

5G technology utilises dynamic resource allocation to handle varying traffic loads and to prioritise specific flows or slices during peak periods. As such, network functions in 5G can allocate resources like bandwidth, power, and spectrum dynamically based on real-time demand, adjusting allocations to meet QoS requirements. Advanced scheduling and resource management algorithms help the network meet high-performance demands, such as ultra-low latency or enhanced throughput, while also saving power when resources are not in use.

QoS Differentiation via Core Network Functions

5GC (the 5G SA core) includes key functions, such as the Session Management Function (SMF) and Policy Control Function (PCF). These play essential roles in QoS enforcement. The SMF handles session establishment and QoS flow creation, while the PCF applies QoS policies based on subscription, network conditions, and user preferences. Taken together, these functions ensure that each session and QoS flow complies with the necessary QoS attributes, adjusting as needed when conditions and requirements change.

Edge Computing for Low Latency

In 5G networks, Multi-Access Edge Computing (MEC) can also play a role in enhancing QoS, particularly for applications that demand ultra-low latency. By processing data closer to the user, MEC reduces the round-trip time, making it ideal for applications like autonomous driving, augmented reality, and smart cities.

New Radio (NR) Capabilities in RAN for QoS

The 5G New Radio (NR) access technology also includes several features designed to improve QoS, for example advanced beamforming, Massive MIMO, and carrier aggregation.

NR supports ultra-reliable low-latency communication (URLLC) by minimising transmission delays and maximising link reliability, which is critical for applications like remote surgery and autonomous control systems.

Use Cases and QoS Considerations in 5G

It’s worth ending this first blog by touching on three of the slice types defined, and the different QoS considerations they require:

• Enhanced Mobile Broadband (eMBB) use cases require high throughput and moderate latency for applications like HD video streaming and virtual reality.
• Ultra-Reliable Low-Latency Communication (URLLC) cases demand extremely low latency and high reliability, essential for critical applications like industrial automation and vehicle-to-everything (V2X) communication.
• Massive Machine-Type Communication (mMTC) involve high device density and power efficiency for IoT applications, prioritising network capacity and scalability over speed.

To summarise, 5G QoS mechanisms deliver a highly customisable and responsive framework designed to support the diverse and stringent requirements that significantly differing use case present, enabling the network to handle a wide range of applications with different QoS needs. It’s these innovations that make 5G networks more adaptable and capable of supporting emerging use cases that were challenging or impractical in previous network generations.

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 with us directly.