The Evolution of 3GPP 5G Network Slice and Service Types (SSTs)

The concept of network slicing has been one of the standout features in 5G (no pun intended). It allows operators to offer logically isolated networks over shared infrastructure, each tailored for specific applications or services. These slices are identified using a combination of the Slice/Service Type (SST) and an optional Slice Differentiator (SD), together forming what is called a Single Network Slice Selection Assistance Information (S-NSSAI).

To ensure global interoperability and support for roaming scenarios, 3GPP standardises a set of SST values. These are intended to provide common ground across public land mobile networks for the most prevalent slice types. Over the course of different 3GPP releases, the list of standardised SST values has grown to reflect emerging use cases and evolving requirements.

The foundation was laid in Release 15, where the first three SST values were introduced. SST 1 represents enhanced Mobile Broadband (eMBB), suitable for high throughput services like video streaming, large file downloads and augmented reality. SST 2 refers to Ultra-Reliable and Low-Latency Communications (URLLC), designed for time-sensitive applications such as factory automation, remote surgery and smart grids. SST 3 is for Massive Internet of Things (mIoT - earlier referred to as mMTC), tailored for large-scale deployments of low-power sensors in use cases such as smart metering and logistics.

The first major extension came with Release 16, which introduced SST 4 for Vehicle-to-Everything (V2X) services. This slice type addresses the requirements of connected vehicles, particularly in terms of ultra low latency, high reliability and localised communication. It was the first time a vertical-specific slice type was defined.

With Release 17, the slicing framework was extended further to include SST 5, defined for High-Performance Machine-Type Communications (HMTC). This slice is aimed at industrial automation and use cases that require highly deterministic and reliable communication patterns between machines. It enhances the original URLLC profile by refining it for industrial-grade requirements.

Recognising the growing importance of immersive services, Release 18 added SST 6, defined for High Data Rate and Low Latency Communications (HDLLC). This slice targets extended reality, cloud gaming and other applications that simultaneously demand low delay and high bandwidth. It goes beyond what enhanced Mobile Broadband or URLLC individually offer by addressing the combination of both extremes. The documentation refers to this as being suitable for extended reality and media services, underlining the increasing focus on immersive technologies and their networking needs.

Finally, Release 19 introduced SST 7 for Guaranteed Bit Rate Streaming Services (GBRSS). This new slice supports services where continuous, guaranteed throughput is essential. It is particularly relevant for live broadcasting, high-definition streaming, or virtual presence applications where quality cannot degrade over time.

This gradual and deliberate expansion of standardised SSTs highlights how 5G is not a one-size-fits-all solution. Instead, it is a dynamic platform that adapts to the needs of different industries. As use cases grow more sophisticated and diverse, having standardised slice types helps ensure compatibility, simplify device and network configuration, and promote innovation.

It is also worth noting that these SST values are not mandatory for every operator to implement. A network can choose to support a subset based on its service strategy. For example, a public network may prioritise SSTs 1 and 3, while a private industrial deployment might focus on SST 5 or 7.

With slicing increasingly central to how 5G will be "monetised" and deployed, expect this list to keep growing in future releases. Each new SST tells a story about where the telecoms ecosystem is heading.

Related Posts: 

• The 3G4G Blog: Is there a compelling Business Case for 5G Network Slicing in Public Networks?
• The 3G4G Blog: Network Slicing using User Equipment Route Selection Policy (URSP)
• The 3G4G Blog: QoS Flow Establishments in 5G Standalone RAN and Core
• The 3G4G Blog: How to Identify Network Slices in NG RAN
• The 3G4G Blog: Network Slicing in NG RAN
• The 3G4G Blog: Network Slicing Tutorials and Other Resources
• The 3G4G Blog: 5G Slicing Templates
• The 3G4G Blog: End-to-end Network Slicing in 5G 

3GPP's 5G-Advanced Workshop Summary

From 28 June to 02 July 2 2021, 3GPP held its first internal workshop on the radio specific content of Release 18, reviewing over 500 company and partner organization’s presentations, to identify topics for the immediate and longer-term commercial needs for:

• eMBB (evolved Mobile BroadBand);
• Non-eMBB evolution;
• Cross-functionalities for both eMBB and non-eMBB driven evolution.

All the documents related to the workshop can be found on the 3GPP website here. The workshop details is available in RWS-210002 while the summary of the RAN Rel-18 workshop is available in RWS-210659.

The following is from 3GPP's news article on 5G-Advanced workshop:

Wanshi Chen, the TSG RAN Chair, summarized that the example areas under each topic serve as a starting point, each subject to further update or removal during the email discussion period - with additional topics still possible, up to the September e-meeting. That RAN#93-e meeting (13-17 September 2021) will see progress on ‘high-level descriptions’ of the objectives for each topic.

List of Topics:

1. Evolution for downlink MIMO, with the following example areas:

• Further enhancements for CSI (e.g., mobility, overhead, etc.)
• Evolved handling of multi-TRP (Transmission Reception Points) and multi-beam
• CPE(customer premises equipment)-specific considerations

2. Uplink enhancements, with the following example areas:

• >4 Tx operation
• Enhanced multi-panel/multi-TRP uplink operation
• Frequency-selective precoding
• Further coverage enhancements

3. Mobility enhancements, with the following example areas:

• Layer 1/layer 2 based inter cell mobility
• DAPS (Dual Active Protocol Stack)/CHO (Conditional HandOver) related improvements
• FR2 (frequency range 2)-specific enhancements

4. Additional topological improvements (IAB and smart repeaters), with the following example areas:

• Mobile IAB (Integrated Access Backhaul)/Vehicle mounted relay (VMR)
• Smart repeater with side control information

5. Enhancements for XR (eXtended Reality), with the following example areas:

• KPIs/QoS, application awareness operation, and aspects related to power consumption, coverage, capacity, and mobility (Note: only power consumption/coverage/mobility aspects specific to XR)

6. Sidelink enhancements (excluding positioning), with the following example areas:

• SL enhancements (e.g., unlicensed, power saving enhancements, efficiency enhancements, etc.)
• SL relay enhancements
• Co-existence of LTE V2X & NR V2X

7. RedCap evolution (excluding positioning), with the following example areas:

• New use cases and new UE bandwidths (5MHz?)
• Power saving enhancements

8. NTN (Non-Terrestrial Networks) evolution

• Including both NR & IoT (Internet of Things) aspects

9. Evolution for broadcast and multicast services

• Including both LTE based 5G broadcast and NR MBS (Multicast Broadcast Services)

10. Expanded and improved Positioning, with the following example areas:

• Sidelink positioning/ranging
• Improved accuracy, integrity, and power efficiency
• RedCap positioning

11. Evolution of duplex operation, with the following example areas:

• Deployment scenarios, including duplex mode (TDD only?)
• Interference management

12. AI (Artificial Intelligence)/ML (Machine Learning), with the following example areas:

• Air interface (e.g., Use cases to focus, KPIs and Evaluation methodology, network and UE involvement, etc.)
• NG-RAN

13. Network energy savings, with the following example areas:

• KPIs and evaluation methodology, focus areas and potential solutions

14. Additional RAN1/2/3 candidate topics, Set 1:

• UE power savings
• Enhancing and extending the support beyond 52.6GHz
• CA (Carrier Aggregation)/DC (Dual-Connectivity) enhancements (e.g., MR-MC (Multi-Radio/Multi-Connectivity), etc.)
• Flexible spectrum integration
• RIS (Reconfigurable Intelligent Surfaces)
• Others (RAN1-led)

15. Additional RAN1/2/3 candidate topics, Set 2:

• UAV (Unmanned Aerial Vehicle)
• IIoT (Industrial Internet of Things)/URLLC (Ultra-Reliable Low-Latency Communication)
• <5MHz in dedicated spectrum
• Other IoT enhancements/types
• HAPS (High Altitude Platform System)
• Network coding

16. Additional RAN1/2/3 candidate topics, Set 3:

• Inter-gNB coordination, with the following example areas:
• Inter-gNB/gNB-DU multi-carrier operation
• Inter-gNB/gNB-DU multi-TRP operation
• Enhancement for resiliency of gNB-CU
• Network slicing enhancements
• MUSIM (Multiple Universal Subscriber Identity Modules)
• UE aggregation
• Security enhancements
• SON (Self-Organizing Networks)/MDT (Minimization of Drive Test)
• Others (RAN2/3-led)

17. Potential RAN4 enhancements 

The latest timeline for Release-17/18 is as shown in the diagram above. 

The official 3GPP Release-18 page is here. This link is better to navigate through features in different 3GPP releases.

Related Posts: 

• The 3G4G Blog: '5G RAN Release 18 for Industry Verticals' Webinar Highlights
• The 3G4G Blog: 3GPP's 5G-Advanced Technology Evolution from a Network Perspective Whitepaper
• The 3G4G Blog: 3GPP RAN Plenary Update and Evolution towards 5G-Advanced
• The 3G4G Blog: Initiative to Remove Non-inclusive terms from 3GPP Specifications
• The 3G4G Blog: Introduction to 5G Reduced Capability (RedCap) Devices
• The 3G4G Blog: 3GPP Standards on Edge Computing
• The 3G4G Blog: ATIS Webinar on '5G Standards Developments in 3GPP Release 16 and Beyond' 

Introduction to 5G Reduced Capability (RedCap) Devices

Back in 2019, we wrote about Release-17 study item called NR-Lite (a.k.a. NR-Light). After the study started, it was renamed as RedCap or Reduced Capability.

5G NR-RedCap (New Radio Reduced Capability Device) is now the official name of NR-Light (or NR-Lite before that). Assuming this was also being discussed in 3GPP as NR-RedCom (New Radio Reduced Complexity Device) earlier. Can anyone confirm 🤔 pic.twitter.com/WZUaJSgQ8s

— 3G4G (@3g4gUK) December 20, 2020

We have now made a video tutorial on RedCap to not only explain what it is but also discuss some of the enhancements being discussed for 3GPP Release-18 (5G-Advanced). For anyone wanting to find out the differences between the baseline 5G devices with RedCap, without wanting to go too much in detail, can see the Tweet image for comparison.

What is 5G reduced capability (RedCap) NR and what will it achieve? - https://t.co/NwWE9bpzVy via @EricssonNetwork @EricssonLabs #Free5Gtraining #3G4G5G #Ericsson #3GPP #5G #5GNR #eMBB #mMTC #URLLC #NRRedCap #RedCap #IoT #NRLight #NRLite #WearableTech #SmartIoT pic.twitter.com/5FbGx9lt5s

— Free 5G Training (@5Gtraining) April 25, 2021

The video and the slides of the tutorial are embedded below:

Beginners: Introduction to 5G Reduced Capability (RedCap) Devices from 3G4G

Related Posts:

• The 3G4G Blog: Challenges and Future Perspectives of Industrial 5G
• The 3G4G Blog: 5G and Industry 4.0
• The 3G4G Blog: What is Industrial IoT (IIoT) and how is it different from IoT?
• Free 6G Training: 6G Localization and Sensing – Technologies, Opportunities and Challenges
• The 3G4G Blog - Ultra Reliability: 5x9s (99.999%) in 3GPP Release-15 vs 6x9s (99.9999%) in 3GPP Release-16
• The 3G4G Blog: 5G Private and Non-Public Network (NPN)
• The 3G4G Blog: Real-life 5G Use Cases for Verticals from China
• The 3G4G Blog: Positioning Techniques for 5G NR in 3GPP Release-16