3GPP Release 16 5G NR Enhancements for URLLC in the RAN & URLLC in the 5G Core network
Introduction:
3GPP Release 16 was “frozen” July 3, 2022. However, two key work items were not completed: Enhancement of the 5G RAN and the 5G Core network to support ultra-high reliability and low-latency communications (URLLC).
The enhancements, especially in the RAN, are essential for 3GPP New Radio (NR) to meet the ITU-R M.2410 Minimum Performance Requirements for the URLLC use case. That was to enable a whole new set of mission critical applications that required either ultra high reliability or ultra low latency (< or =1 ms in the data plane and < or =10ms in the control plane) or both.
Yet URLLC in the RAN and the associated URLLC in the RAN Conformance Test specification still have not been completed (see below)!
Overview of URLCC Enhancements:
The main functionalities introduced were the support of redundant transmission, QoS monitoring, dynamic division of the Packet Delay Budget, and enhancements of the session continuity mechanism.
The 3GPP Rel 16 URLLC in the RAN spec, once complete and performance tested, is needed to meet the ITU-R M.2410 URLLC Performance Requirements.
The 5G NR Physical Layer is improved for the support of URLLC in the RAN in several ways: new DCI formats, Enhanced PDCCH monitoring capability, Sub-slot based HARQ-ACK feedback, Two HARQ-ACK codebooks constructed simultaneously, PUSCH enhancements, Enhanced inter UE Tx prioritization/multiplexing and Multiple active configured grant configurations for a BWP.
Current Status:
The most recent URLLC in the RAN spec dated December 2022 is 96% complete as per:
| 830074 | NR_L1enh_URLLC | Physical Layer Enhancements for NR Ultra-Reliable and Low Latency Communication (URLLC) | Rel-16 | R1 | 22/12/2022 | RP-191584 | history | 2019/03/26 | 26/06/2019 | 26/6/19: WID:RP-190726->RP-191584 |
The URLLC in the RAN Conformance Test spec is only 90% complete as per:
| 900054 | NR_L1enh_URLLC-UEConTest | … UE Conformance Test Aspects – Physical Layer Enhancements for NR URLLC | Rel-16 | R5 | 22/12/2022 | RP-202566 | history | 2021/01/06 | 20/06/2022 | 22/3/22: Compl:16 ; 20/6/22: Rapporteur: Huawei->Chunying GU, Huawei; Rap eMail: ->guchunying@huawei. |
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Here are the key 3GPP Rel16 URLLC work items from https://www.3gpp.org/dynareport?code=WI-List.htm
- 830074 NR_L1enh_URLLC Physical Layer Enhancements for NR Ultra-Reliable and Low Latency Communication (URLLC)
- 800095 FS_NR_L1enh_URLLC… Study on physical layer enhancements for NR UR Low Latency Cases
- 830174 NR_L1enh_URLLC-Core… Core part: Physical Layer Enhancements for NR URLLC
- 830274 NR_L1enh_URLLC-Perf… Perf. part: Physical Layer Enhancements for NR URLLC (R4)
- 900054 NR_L1enh_URLLC-UEConTest… UE Conformance Test Aspects – Physical Layer Enhancements for NR URLLC (R5)
References:
https://www.3gpp.org/dynareport?code=WI-List.htm
https://www.3gpp.org/dynareport?code=status-report.htm
https://www.3gpp.org/dynareport?code=FeatureOrStudyItemFile-830074.htm
https://www.3gpp.org/technologies/urlcc-2022
https://techblog.comsoc.org/category/3gpp-release-16
Executive Summary: IMT-2020.SPECS defined, submission status, and 3GPP’s RIT submissions
5G Specifications (3GPP), 5G Radio Standard (IMT 2020) and Standard Essential Patents
Another Opinion: 5G Fails to Deliver on Promises and Potential
Does anyone realize that the failure of 3GPP to complete URLLC in the RAN has been a key reason there are no 5G killer apps? That is because neither mission critical apps requiring ultra high reliability AND real time control apps requiring ultra low latency (e.g. <=1 ms in data plane) could not exist as there was no 3GPP spec or ITU-R M.2150 standard to meet ITU-R M.2410 performance reqts for URLLC use case!