Tantra Analyst

Chronicles of 3GPP Rel. 17 Part 2: Defining the future of 5G

I just returned from a whirlwind session of 3GPP RAN Plenary #86, held at the beautiful beach town of Sitges in Spain. The meeting finalized a comprehensive package with more than 30 Study and Work Items (SI and WI) for Rel 17. With a mix of new capabilities and significant improvements to existing features, Rel 17 is set to define the future of 5G. It is expected to be completed by mid or end of 2021.

<<Side note, if you would like to understand more about how 3GPP works, read my series “Demystifying Cellular Standards and Licensing” >>

Although the package looks like a laundry list of features, it gives a window into the strategy and capabilities of different member companies. Some are keen on investing in new, path-breaking technologies, while others are looking to optimize existing features or working on the fringe or very specific areas.

The Rel. 17 SI and WIs can be divided into three main categories.

Blazing new trail

These are the most important new concepts being introduced in Rel. 17 that promise to expand 5G’s horizon. 

XR (SI) – The objective of this is to evaluate and adopt improvements that make 5G even better suited for AR, VR, and MR. It includes evaluating distributed architecture harnessing the power of edge-cloud and device capabilities to optimize latency, processing, and power. Lead (aka Rapporteur) – Qualcomm

NR up to 71 GHz (SI and WI) – This is in the new section because of a twist. The WI is to extend the current NR waveform up to 71 GHz, and SI is to explore new and more efficient waveforms for the 52.6 – 71 GHz band.  Lead – Qualcomm and Intel 

NR-Light (SI) – The objective is to develop cost-effective devices with capabilities that lie between the full-featured NR and Low Power Wireless Access (e.g., NB-IoT/eMTC). For example, devices that support 10s or 100 Mbps speed vs. multi-Gigabit, etc. The typical use cases are wearables, Industrial IoT (IIoT), and others. Lead – Ericsson

Non-Terrestrial Network (NTN) support for NR & NB-IoT/eMTC (WI) – A typical NTN is the satellite network. The objective is to address verticals such as Mining and Agriculture, which mostly lie in remote areas, as well as to enable global asset management, transcending contents and oceans. Lead – MediaTek and Eutelsat

Perfecting the concepts introduced in Rel. 16 

Rel. 16 was a short release with an aggressive schedule. It improved upon Rel. 15 and brought in some new concepts. Rel 17 is aiming to make those new concepts well rounded. 

Integrated Access & Backhaul – IAB (WI) – Enable cost-effective and efficient deployment of 5G by using wireless for both access and backhaul, for example, using relatively low-cost and readily available millimeter wave (mmWave) spectrum in IAB mode for rapid 5G deployment. Such an approach is especially useful in regions where fiber is not feasible (hilly areas, emerging markets).  Lead – Qualcomm

Positioning (SI) – Achieve centimeter-level accuracy, based only on cellular connectivity, especially indoors. This is a key feature for wearables, IIoT, and Industry 4.0 applications.  Lead – CATT (NYU)

Sidelink (WI) – Expand use cases from V2X-only to public safety, emergency services, and other handset-based applications by reducing power consumption, reliability, and latency. Lead – LG 

Small data transmission in “Inactive” mode (WI) – Enable such transmission without going through the full connection set-up to minimize power consumption. This is extremely important for IIoT use cases such as sensor updates, also for smartphone chatting apps such as Whatsapp, QQ, and others. Lead – ZTE

 IIoT and URLLC (WI) – Evaluate and adopt any changes that might be needed to use the unlicensed spectrum for these applications and use cases. Lead – Nokia 

Fine-tuning the performance of basic features introduced in Rel. 15

Rel. 15 introduced 5G. Its primary focus was enabling enhanced Broadband (eMBB). Rel. 16 enhanced many of eMBB features, and Rel. 17 is now trying to optimize them even further, especially based on the learnings from the early 5G deployments.

Further enhanced MIMO – FeMIMO (WI) – This improves the management of beamforming and beamsteering and reduces associated overheads. Lead – Samsung

Multi-Radio Dual Connectivity – MRDC (WI) – Mechanism to quickly deactivate unneeded radio when user traffic goes down, to save power. Lead – Huawei

Dynamic Spectrum Sharing – DSS (WI) – DSS had a major upgrade in Rel 16. Rel 17 is looking to facilitate better cross-carrier scheduling of 5G devices to provide enough capacity when their penetration increases. Lead – LG

Coverage Extension (SI) – Since many of the spectrum bands used for 5G will be higher than 4G (even in Sub 6 GHz), this will look into the possibility of extending the coverage of 5G to balance the difference between the two.  Lead – China Telecom and Samsung

Along with these, there were many other SI and WIs, including Multi-SIM, RAN Slicing, Self Organizing Networks, QoE Enhancements, NR-Multicast/Broadcast, UE power saving, etc., was adopted into Rel. 17.

Other highlights of the plenary

Unlike previous meetings, there were more delegates from non-cellular companies this time, and they were very actively participating in the discussions, as well. For example, a representative from Bosch was a passionate proponent for automotive needs in Slidelink enhancements. I have discussed with people who facilitate the discussion between 3GPP and the industry body 5G Automotive Association (5GAA). This is an extremely welcome development, considering that 5G will transform these industries. Incorporating their needs at the grassroots level during the standards definition phase allows the ecosystem to build solutions that are market-ready for rapid deployment. 

There was a rare, very contentious debate in a joint session between RAN and SA groups. The debate was to whether set RAN SI and WI completion timeline to 15 months, as planned now, or extend it to 18 months. The reason for the latter is TSG-SA being late with Rel. 16 completion, and consequently lagging in Rel. 17. Setting an 18-month completion target for RAN will allow SA to catch up and align both the groups to finish Rel. 17 simultaneously. However, RAN, which runs a tight ship, is not happy with the delay. Even after a lengthy discussion, the issue remains unresolved. 

<<Side Note: If you would like to know the organization of different 3GPP groups, including TSGs, check out my previous article “Who are the unsung heroes that create the standards?” >>

It will be amiss if I don’t mention the excellent project management skills exhibited by the RAN chair Mr. Balazs Bertenyi of Nokia Bell Labs. Without his firm, yet logical and unbiased decision making, it would have been impossible to finalize all these things in a short span of four days. 

In closing

Rel. 17 is a major release in the evolution of 5G that will expand its reach and scope. It will 1) enable new capabilities for applications such as XR; 2) create new categories of devices with NR-Light; 3) bring 5G to new realms such as satellites; 4) make possible the Massive IoT and Mission Critical Services vision set out at the beginning of 5G; while also improving the excellent start 5G has gotten with Rel. 15 and eMBB. I, for one, feel fortunate to be a witness to see it transform from concept to completion.

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