Whilst many service providers are currently deploying and optimizing their 5G NR (New Radio) networks using 3GPP Release 15/16 compliant equipment, 3GPP is pressing on finalizing Release 17 (2022) with eyes now focused on Release 18 “5G Advanced”.
Currently, we are at the very early stages of Release 18 with 3GPP contributors identifying topics and enhancements to include as “work items”. As you can see from Figure 1, Release 18 won’t be fully frozen till 2024!
Unfortunately, to truly comprehend all the Release 18 items you must be quite familiar with existing Release 15/16/17 features. This is mainly because Release 18 items typically relate to an “evolution” or “enhancement” of an existing feature or capability. I’ve summarized some of the key areas Release 18 aims to evolve/enhance. In addition, we will have to wait until various future Release 18 “3GPP workshops” have taken place before being able to quote actual improvement figures and a definitive list of RAN features.
Historically, each 3GPP Release further enhances the downlink performance. It’s no surprise that Release 18 will aim to do the same. The focus will be on optimizing the use of Massive MIMO, as well as the evolution of multi-TRP (Transmission Reception Points) and multi-beam operation. These enhancements aim to increase performance, as well as increase efficiency.
The uplink performance is typically reduced due to the nature of a device and it’s limited power and antenna capabilities. As such, a combination of features to enhance UL Capacity and UL coverage are proposed. For example, using multi-panel and multi-TRP uplink operation, as well as the modification of uplink channels to facilitate more repetition.
One key goal is to the reducing the mobility procedure time, as well as the interrupt duration to the data flow. Release 18 will aim to improve on the Release 16 DAPS (Dual Active Protocol Stack) and CHO (Conditional HandOver) features which decrease mobility interruption time (the time when a user is not able to transmit or receive data during the handover period). In addition, Release 18 also focuses on Layer 1/Layer 2 based inter cell mobility. This will assist in further decreasing the mobility interrupt time and optimizing the process, especially in a virtual RAN environment.
Release 18 aims to improve the IAB (Integrated Access and Backhaul) feature which was added in 3GPP Release 16 by facilitating Mobile IAB and well as VMR (Vehicle Mounted Relay) features. In addition, the use of smart repeaters with “side control information” is also being discussed. These provide intelligent amplify-and-forward operation in a system with TDD (Time Division Duplexing) access and multi-beam operation. Overall, providing greater efficiency.
When discussing 5G use cases XR (eXtended Reality) is on the list. Release 18 aims to further enhance power consumption/coverage/mobility specific to XR operation.
Sidelink relates to device to device communication and was originally added to as part of ProSE (Proximity Services) in 3GPP Release 12. However, it has been incorporated into many other aspects including NR V2X (Vehicle to Everything). Release 18 targets enhancements related to unlicensed frequency operation, power saving and various efficiency enhancements, as well as the use of Sidelink Relays.
5G NR RedCap (Reduced Capabilities) relates to the use cases that don’t fall clearly in one of the original 5G service types (eMBB, URLLC and mMTC). Instead, RedCap incorporates other devices such as wearables (smart watches, AR/VR goggles, etc), video surveillance evolution as well as industrial wireless sensors. 3GPP Release 18 aims to focus on enhancements for RedCap devices, as well as identifying new use cases.
NTN (Non-Terrestrial Networks) for 5G was first seen in 3GPP Release 16. However, recently there has been growing interest in 5G Satellite based solutions. As such, Release 18 continues this drive by focusing on both NR & IoT (Internet of Things) aspects of NTN evolution.
Whilst broadcast and multicast services have been part of LTE from the outset, they have also been added to NR. Unfortunately, most users prefer on-demand services which don’t fit nicely into a broadcast/multicast model. However, there are various use-cases that utilize broadcast and MBS (Multicast Broadcast Services), such as public safety. As such, Release 18 aims to keep evolving these services so that they may be incorporated into existing and future use-cases.
Many devices incorporate GPS (Global Positioning System) for the end user device apps (e.g. google maps). However, the GPS is not typically used as part of network device positioning. As such, 3GPP standards include alternative positioning solutions. Release 18 aims to provide improved accuracy, integrity, and power efficiency (i.e. the energy consumed when determining the devices position). It also aims to improve positioning for Sidelink operation and RedCap devices.
AI (Artificial Intelligence) and ML (Machine Learning) have already started to find their way into 4G/5G networks. As such, it’s no surprise that Release 18 is discussing how AI/ML can improve the air interface performance, such as using AI to identify the most efficient scheduling mechanism for the users in the cell. The use of AI/ML also extends into the NG-RAN (Next Generation – Radio Access Network). For example, by identifying mobility patterns of devices in the area, the system can adapt the cell parameters /coverage to overall improve the performance, i.e. more efficiency with less dropped calls.
Energy Saving has been a key part of 3GPP system design for both the devices and NG-RAN. Release 18 aims to continue the evolution in Network Energy saving. Not surprising the use of AI/ML can also play a part in optimizing and Energy Saving algorithms.
The actual list of RAN changes proposed for 3GPP Release 18 will be extensive. Expect to see a combination of enhancements to existing features, as well as the support of new capabilities, such as enhancing and extending the support of 5G beyond 52.6GHz.
I’ve briefly summarized some of the key areas 3GPP Release 18 will be focusing on in terms of the evolution of the 5G RAN. Not surprisingly, there are still many discussions and decisions to be made prior to the Stage 2 freeze in 2023. It is also worth noting that 3GPP Release 18 will also incorporate many work items related to the 5G Core…but that’s another Mpirical technology blog.