The 5G Standard

Rel-18 Status and Rel-19 Progress in TSG RAN

Mar 07, 2024

By Wanshi Chen, TSG RAN Chair

First published Nov 2023, in Highlights Issue 07 

The first release of 5G’s “2nd phase” of standardization in 3GPP, Release 18 (aka 5G-Advanced), is close to the finish line in TSG RAN. At the same time, discussion on Release 19 is ongoing, aiming at having the Rel-19 package approval for RAN WG1, 2 and 3 (RAN1/2/3) completed by the end of 2023.

Release 18 Status in TSG RAN

The release is providing a steady evolution in terms of:

  • Balanced mobile broadband evolution vs. further vertical domain expansion,
  • Balanced immediate vs. longer term commercial needs, and
  • Balanced device evolution vs. network evolution.

The work started in 2Q’2022 in RAN1, and in 3Q’2022 in RAN2/3/4, in the usual staggered manner. Rel-18 was planned to have the functional freeze in September 2023 for RAN1, and in December 2023 for RAN2/3/4, forming an 18-month duration for the release.

Despite the challenges of the slow resumption of face-to-face meetings from the second half of 2022 and the inevitable negative impact on the meeting efficiency, RAN was able to declare that functional freeze in RAN1 on time.

To ensure sufficient specification stability, RAN1 will now be dedicated to Rel-18 maintenance in 4Q’23. The functional freeze for RAN2/3/4 is expected to be in December 2023, with the first ASN.1 review scheduled for March’24 and the ASN.1 freeze date of June’24.

Release 18 and Release 19 timelines.

Release 19 Workshop in RAN

The discussion on Rel-19 in RAN had a strong start with the Rel-19 workshop. The two days of sessions in June 2023 drew strong interest around the globe, with ~480 submissions presented by over 80 different companies & organizations.

Release 19 will primarily focus on continuing investing in 5G-Advanced commercial deployments to further improve performance and address critical needs, including:

  • Continuing balanced evolutions as in Rel-18, and
  • Addressing real and urgent commercial deployment needs.

Release 19 can also serve as a bridge to 6G, including the strong interest to initiate some studies (e.g., channel modeling for new spectrum such as 7-24GHz, etc.). The following list (and graphic below) illustrates the categorization of the topics based on the contributions to the workshop. The overall Rel-19 load is expected to be lower than Rel-18.

Release 19 in RAN#101 (September’2023)

RAN#101 (Bangalore, September 2023) provided the first consolidation of the potential Rel-19 projects. A first-order Time Unit (TU) estimate was provided for some RAN1/2/3-led projects. Some TUs were also reserved for purposes such as necessary cushion, flexibility for WG chairs, preparation for urgent commercial needs, and dedicated handling of inter-WG/inter-TSG matters.

For RAN1, the first-order TU estimate was provided for the following RAN1-led projects:

  • AI (Artificial Intelligence)/ML (Machine Learning) for Air interface
  • MIMO Evolution
  • Duplex Evolution
  • Ambient IoT
  • Network energy savings
  • ISAC & Exploring study in new spectrum (7-24 GHz)

With the above arrangement, RAN1 may have room for up to 2 additional RAN1-led small projects.

For RAN2, the first-order TU estimate was provided for the following RAN2-led projects:

  • Mobility Enhancements
  • Enhancements for XR
  • NTN (Non-Terrestrial Networks) evolution for NR
  • NTN (Non-Terrestrial Networks) evolution for IoT
  • AI/ML for Air interface SI (Mobility)

With the above arrangement, RAN2 may have room for up to 3 additional RAN2-led small projects.

For RAN3, the first-order TU estimate was provided for the following RAN3-led projects:

  • AI/ML for NG-RAN
  • SON/MDT Enhancements
  • Additional Topological Enhancements

With the above arrangement, RAN3 may not have any room for additional RAN3-led projects.

Note that the first discussion for potential RAN4-led projects occurred during RAN#101 as well.

Decisions in December

In December 2023, TSG RAN (RAN#102) is primarily focusing on projects led by RAN 1, 2, and 3, then focusing on the projects led by RAN4 in March 2024.

It is expected that RAN#102 will be a busy meeting, in order to finalize the set of RAN1/2/3-led projects including the final drafting of corresponding SIDs/WIDs. All the discussion will be based on the progress so far, including agreements and summaries achieved in the Rel-19 workshop (June 2023) and during RAN#101 in September.

As probably the last release dedicated to 5G NR in RAN, careful discussion and management are necessary to ensure Rel-19 continues to serve all critical commercial needs and that it stands ready to provide a bridge to 6G.

Release 19