Future Railway Mobile Communication System (FRMCS)

I have been meaning to write on this topic for a very long time. The discussion started back in 2016 when the limitations of GSM-R were obvious and it was recognised that a successor will be needed sooner or later. The International Railway Union (UIC) published a user requirement specification in their paper “Future Railway Mobile Communication System - FRMCS”. This is available on 3GPP server as liaison statement S1-161250.

As 3GPP notes in their article, this was the trigger for them to go ahead and start the studies. Then in Release 16, 3GPP TS 22.289 "Mobile communication system for railways" outlined the requirements for railway communication, beyond the 3GPP Future Railway Mobile Communication System (FRMCS) Phase 1 specs. Details are available on this post here.

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The latest version of 3GPP TR 22.889, Study on Future Railway Mobile Communication System; Stage 1 is from Release 17. The introduction to the document clarifies:

The railway community is considering a successor communication system to GSM-R, as the forecasted obsolescence of the 2G-based GSM-R technology is envisaged around 2030, with first FRMCS trial implementations expected to start around 2020. 

The Future Railway Mobile Communication System (FRMCS) Functional Working Group (FWG) of the International Union of Railways (UIC) have investigated and summarised their requirements for the next generation railway communication system in the Future Railway Mobile Communication User Requirements Specification (FRMCS URS). The present document is based on this input given by the UIC/ETSI TC-RT 

Study on FRMCS Evolution (FS_eFRMCS), available as SP-201038 clarifies:

The UIC FRMCS programme was recently releasing stable version 5.0.0 of the User Requirement Specification, version 2.0.0 of the Functional Use Cases and a new specification item, version 1.0.0 of the Telecom On-Board System - Functional Requirements Specification, as a further step in the evolution of the FRMCS specifications. The UIC FRMCS Programme is developing all the technical conditions for the 5G FRMCS, with the main objective to make available a “FRMCS First Edition” ecosystem available for procurement by Q1 2025.

The UIC FRMCS 3GPP Task Force has been identifying and analyzing impact of this newly released set of FRMCS specifications on existing use cases and requirements collected in TR 22.889. The UIC FRMCS 3GPP Task Force analysis has concluded that refining existing use cases, defining new use cases such as merging railway emergency communications and real-time translation of conversation, and deriving potential new requirements, will be necessary to align FRMCS and 3GPP specifications. The potential impact on normative work is estimated to be limited and much less compared to the study work.

As approved in SA1#90-e (S1-202245), TR 22.889 has now been re-named to TR 22.989 from Rel-18 onwards (latest version is TR 22.989 v18.0.0) to make it visible to the Rail community to be able to follow the 3GPP normative work in line with their needs. It is of most importance for the Rail community that specifications from different organisations (i.e. UIC, 3GPP and ETSI) are all aligned.

Due to the expected 3GPP work overload in Release 18 (SA1 and downstream groups), it is proposed to reduce the scope of the present Rel-18 study to evolution of critical applications related use cases only already identified by UIC – what is really essential for the railways as part of the “FRMCS First Edition” and the migration phase from GSM-R to FRMCS. 

Study of non-essential use cases (e.g. evolution of performance and business use cases) shall be postponed to Rel-19.

This plan is from 2019 so quite likely that it is already outdated. It does provide an idea on different steps and trial plans. Some of this was also covered in the 5G RAN Release 18 for Industry Verticals Webinar detailed here.

Finally, as this image from Arthur D. Little highlights, there is a lot of other interest in addition to FRMCS for 5G in railway. Report here.

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• The 3G4G Blog: 3GPP's 5G-Advanced Workshop Summary
• The 3G4G Blog: 3GPP's 5G-Advanced Technology Evolution from a Network Perspective Whitepaper
• Telecoms Infrastructure Blog: Bringing Connectivity to Underground Rail Network
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Qualcomm Explains 5G Millimeter Wave (mmWave) Future & Integrated Access and Backhaul (IAB)

We have covered various topics in our blog posts on millimeter wave spectrum and even going beyond 52.6 GHz in FR2. A Qualcomm webinar from back in January expands on many of the topics that I looked superficially in various posts (links at the bottom).

The following is edited from the Qualcomm blog post:

5G NR in unlicensed spectrum (NR-U) was standardized in Release 16 and it is a key enabler for the 5G expansion to new use cases and verticals, providing expanded spectrum access to mobile operators, service providers, and industry players. At the same time, we are starting to push the mmWave boundary to even higher bands toward the sub-Terahertz (i.e., >100 GHz) range. Expected in Release 17, 5G NR will support spectrum bands up to 71 GHz, leveraging the 5G NR Release 15 scalable numerology and flexible framework. This opens up 5G to operate in the globally unlicensed 60 GHz band, which can fuel a broad range of new applications and deployments.

One daunting challenge that mobile operators will face when expanding 5G mmWave network coverage is the cost of deploying additional base stations for mmWave, which usually requires new fiber optics backhaul installations. Release 16-defined IAB allows a base station to not just provide wireless access for its user devices (e.g., smartphones) but also the ability to backhaul wirelessly via neighboring base stations using the same mmWave spectrum. IAB opens the door to more flexible densification strategies, allowing mobile operators to quickly add new base stations to their networks before having to install new fiber to increase backhaul capacity. 

Release 16 established foundational IAB capabilities, such as dynamic topology adaptation for load balancing and blockage mitigation, and Release 17+ will further enhance IAB by bringing new features like full-duplex operation, topology redundancy, and ML-based network management.

Beyond IAB, there is a rich roadmap of other new features that can further improve 5G mmWave system performance and efficiency. The webinar embedded below is presented by Ozge Koymen, Senior Director, Technology, Qualcomm Technologies, Inc. It covers the following topics:

• Qualcomm's vision for 5G mmWave and the new opportunities it poises to bring for the broader ecosystem
• mmWave capabilities and enhancements coming in Release -16 and beyond
• Qualcomm’s role in mobilizing and democratizing 5G mmWave to usher in new experiences
• Latest update on the global commercial rollout of 5G mmWave networks and devices

Slides of the presentation are available here.

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3GPP's 5G-Advanced Technology Evolution from a Network Perspective Whitepaper

China Mobile, along with a bunch of other organizations including China Unicom, China Telecom, CAICT, Huawei, Nokia, Ericsson, etc., produced a white paper on what technology evolutions will we see as part of 5G-Advanced. This comes not so long after the 3GPP 5G-Advanced Workshop which a blogged about here.

The abstract of the whitepaper says:

The commercialization of 5G networks is accelerating globally. From the perspective of industry development drivers, 5G communications are considered the key to personal consumption experience upgrades and digital industrial transformation. Major economies around the world require 5G to be an essential part of long-term industrial development. 5G will enter thousands of industries in terms of business, and technically, 5G needs to integrate DOICT (DT - Data Technology, OT - Operational Technology, IT - Information Technology and CT - Communication Technology) and other technologies further. Therefore, this white paper proposes that continuous research on the follow-up evolution of 5G networks—5G-Advanced is required, and full consideration of architecture evolution and function enhancement is needed.

This white paper first analyzes the network evolution architecture of 5G-Advanced and expounds on the technical development direction of 5G-Advanced from the three characteristics of Artificial Intelligence, Convergence, and Enablement. Artificial Intelligence represents network AI, including full use of machine learning, digital twins, recognition and intention network, which can enhance the capabilities of network's intelligent operation and maintenance. Convergence includes 5G and industry network convergence, home network convergence and space-air-ground network convergence, in order to realize the integration development. Enablement provides for the enhancement of 5G interactive communication and deterministic communication capabilities. It enhances existing technologies such as network slicing and positioning to better help the digital transformation of the industry.

The paper can be downloaded from China Mobile's website here or from Huawei's website here. A video of the paper launch is embedded below:

Nokia's Antti Toskala wrote a blog piece providing the first real glimpse of 5G-Advanced, here.

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• The 3G4G Blog: '5G RAN Release 18 for Industry Verticals' Webinar Highlights
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• Connectivity Technology Blog: Ericsson Explains Internet of Drones and 3GPP UAV Roadmap
• The 3G4G Blog: 3GPP RAN Plenary Update and Evolution towards 5G-Advanced
• The 3G4G Blog: Introduction to 5G Reduced Capability (RedCap) Devices
• The 3G4G Blog: 3GPP Standards on Edge Computing
• Connectivity Technology Blog: 5G Drone Cell Towers
• Free 6G Training: Pre-Study of B5G and 6G in China
• Free 6G Training: China's IMT-2030 (6G) Promotion Group Releases 6G Whitepaper
• The 3G4G Blog: Real-life 5G Use Cases for Verticals from China
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• Free 6G Training: Huawei talks about Beyond 5G, 5.5G and 6G
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'5G RAN Release 18 for Industry Verticals' Webinar Highlights

5G PPP held a virtual workshop on RAN Release 18 for Industry Verticals on June 23rd, 2021. The workshop was organised by 3GPP Market Representation Partners (MRPs): 5G-IA, 5GAA, 5G-ACIA and PSCE.

It features a fireside chat with new 3GPP RAN TSG Chair, Wanshi Chen. In addition to this, the workshop then provides a deep dive on new requirements from verticals, spanning automotive (5GAA), manufacturing (5G-ACIA), critical communications and public safety (TCCA with PSCE), broadcasting and media (5G-MAG), satellite (ESOA), rail (UIC), maritime (IALA) and energy (EUTC).

5G-SOLUTIONS came on board as a 5G PPP project supporting verticals with the 5G-EVE and 5G-VINNI 5G network infrastructures alongside RAN specialists doing standardisation work applicable to multiple verticals.

The video of the webinar is embedded below. In addition, you will find timings of when a particular talk starts and a link to the slides (if shared/available)

Timings:

• 0:04:21 Fireside chat with Wanshi Chen, Qualcomm and 3GPP RAN TSG Chairman
• 0:21:00 NTN Requirements in Rel-18 by Nicolas Chuberre, Thales Alenia Space (slides)
• 0:31:40 Multiple verticals: Andrea Di Giglio, 5G SOLUTIONS (slides)
• 0:36:35 Media and Broadcasting: David Vargas, BBC and 5G-MAG Chair of CD-T WG, Proposals for 3GPP RAN Rel-18 (slides)
• 0:43:19 Maritime: Hyounhee Koo, Synctechno and IALA, Maritime Requirements on 3GPP Rel 18 RAN Studies/Works Priorities (slides)
• 0:46:12 Rail: Ingo Wendler, UIC, NR Narrowband Channel Bandwidth - Railway Use Case (slides)
• 0:50:02 Utilities: Julian Stafford, EUTC 3GPP RAN Rel-18 Requirements (slides)
• 0:58:35 Utilities: Erik Guttman, Samsung 5G Smart Energy Infrastructure (slides)
• 1:05:45 Multiple verticals: Mathew Webb, Huawei and 3GPP RAN 3GPP Release 17 and Release 18 support for industry verticals (slides)
• 1:15:19 Public Safety/Critical Communications: Tero Pesonen, TCCA Chair, joint presentation with PSCE, 3GPP MRP Mini Workshop: 3GPP Rel 18. Requirements from industry verticals (slides)
• 1:20:15 Multiple verticals: Thierry Berisot, Novamint and 3GPP RAN, Industry Verticals and Rel-18 RAN (slides)
• 1:32:56 Manufacturing/IIoT: Michael Bahr, Siemens and 5G-ACIA WG 1Chair and An Xueli, Huawei and 5G-ACIA WG1 Vice Chair 3GPP RAN Rel-18 for Industry Verticals (slides)
• 1:42:20 Automotive: 5GAA Maxime Flament, CTO Input to RAN 18 Rel-18 Workshop (slides)
• 1:53:35 Interactive Session 2
• 2:04:36 Passive IoT for 5G-Advanced, Mathew Webb, Huawei and 3GPP RAN (slides)
• 2:14:59 Template A for Interactive Session 2
• 2:20:40 Critical Communications / Public Safety requirements for Release 18 
• 2:26:00 Closing Remarks

Official page here.

The slide above nicely summarizes 3GPP RAN Verticals up to Release 17.

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• The 3G4G Blog: 3GPP's 5G-Advanced Workshop Summary
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Qualcomm Demoes Sub-band Half Duplex (SBHD)

Qualcomm has been busy promoting its advanced 5G solutions these last few months in the run up to Mobile World Congress (MWC). You can find a detailed write-up on their website here as well as a feature which they did with RCR wireless here.

One of the innovations that caught my attention was Sub-band Half-Duplex (SBHD). In the first glance it looks like the Enhanced Interference Mitigation & Traffic Adaptation (eIMTA) solution we discussed long back here.

Their article talks about how their 5G multi-cell over-the-air (OTA) test network can now support subband half-duplex, allowing for more flexible service multiplexing as well as improved latency and coverage. 

While you can get an idea of what SBHD is from the diagram above, here is a video explaining it further.

Let us know what do you think about how important will this feature be in future 5G networks.

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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

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