6G Requirements and Potential Enabling Technologies

5G standard is still evolving with new 3GPP releases issued periodically, leading to 5G-Advanced and possibly 5G-Advanced Pro in coming years. However, all major players (researchers, vendors, mobile network operators, regulators) have already started their 6G activities in line with the tradition of having G+ every 10 years. This blog post provides an overview of the current state of 5G, outlines 6G requirements, and discusses some 6G potential enabling technologies from mobile network operators’ perspective.

The Current State of 5G

The 5th generation mobile network (5G) is a global standard, developed and maintained by the 3rd Generation Partnership Project (3GPP). It is designed to deliver higher multi-Gbps peak data speed, massive connectivity, more reliability, low latency, high energy efficiency, and a more uniform user experience to more users [1].

Below is the typical 5G triangle, which is composed of 3 key components [2]. Existing and potential 5G use cases can be mapped onto this triangle.

• Bandwidth: enhanced Mobile Broadband (eMBB)
• Latency: ultra-Reliable Low-Latency Communications (uRLLC)
• Connection density: massive Machine-Type Communications (mMTC)

A large number of mobile operators have already deployed 5G networks. However, the full potential of 5G has not yet been realized. 5G is now mainly serving consumers (e.g., high-speed internet), not the many potential verticals (e.g., manufacturing, agriculture, healthcare, smart cities, … etc.) [3]. Indeed, 5G is a game-changer for many industry verticals, but not yet a game-winner. This is because of:

• Challenges facing business (e.g., lack of business cases, delay in ecosystem readiness) and
• Challenges facing mobile operators (e.g., not willing to upgrade network unless there is a clear business demands, not straightforward to develop business models for charging for various verticals).

The success of 5G in terms of business (generating growth and revenue) will have a significant impact on how 6G will develop in the future.

The Current State of 6G

The 5G standard is still developing, with new 3GPP releases coming out on a regular basis, leading to 5G-Advanced and perhaps 5G-Advanced Pro in the years to come [4]. However, in accordance with the custom of having G+ every ten years, all key players (researchers, manufacturers, mobile network operators, and regulators) have already begun their research activities around the 6th generation mobile network (6G) [5], which will also be a global standard that is developed and maintained by 3GPP.

It is expected that 6G takes all 5G capabilities to the next level, offers ubiquitous coverage (land, sea, sky, space), and adopts AI-native capabilities as well as other promising technologies in physical layers. Unless a major breakthrough happens in the physical layer in the next few years, 6G is likely to be simply 5G Advanced Pro, powered by AI-native capabilities.

Below are some 6G key requirements [6][7].

Perception of infinite capacity:

• Higher data rates for immersive virtual environments such as Metaverse & extended reality (xR)
• Higher connection density to support the ever-increasing demands of connected devices

Resilience and security:

• Resilience = high robustness + fast recovery over failure
• Secure,  reliable, and available under all circumstances

Sustainability:

• Significant reduction in energy consumption per bit
• Green energy for RAN (e.g. energy produced by nearby solar panel and stored in battery bank)
• Fully recyclable components

Ubiquitous 3D coverage:

• Elimination of dead spots
• High-speed wireless connectivity throughout land, sea, sky, and space

The table below compares 5G and 6G KPIs [8][9].

KPI	5G	6G
Peak data rate	20 Gbps	1 Tbps
User experienced data rate	100 Mbps	1 Gbps
Peak spectral efficiency	30 b/s/Hz	60 b/s/Hz
User experienced  spectral efficiency	0.3 b/s/Hz	3 b/s/Hz
End-to-End latency	10 ms	1 ms
Radio-only  latency	1 ms	100 microseconds
Block Error Rate (BLER)	10-5	10-9
Connection density	106 devices/Km2	107 devices/Km2
Network  energy efficiency	Not Specified	1 pJ/b
Position accuracy	1 m	0.1 m
Mobility	500 Km/h	1000 Km/h
Maximum frequency	100 GHz	10 THz
Maximum bandwidth	1 GHz	100 GHz
Satellite integration	Partial	Fully

Potential Enabling Technologies for 6G

There are many interesting technologies that have the potential to enable 6G. The focus here is on some 6G enabling technologies that have the potential to noticeably contribute to mobile operators’ businesses in terms of the creation of revenue and growth. Below are some enabling technologies and their benefits.

AI-native design for better teaming:

• Predict anomalies in network operation -> take corrective action on time -> enhance network reliability and achieve OPEX reduction
• Optimized network slicing -> can accommodate new network slices for additional industry verticals -> enhance network efficiency and reduce CAPEX

Open RAN:

• Open interfaces for interoperability
• Open ecosystem (no vendor lock-in)
• Innovation
• Quick Time-to-Market
• Intelligent Management
• Significant reduction in OPEX & CAPEX

In-band full-duplex communication:

• Doubling spectral efficiency -> Can get the job done using ½ of the available block of spectrum -> in the next spectrum auction, purchase only ½ of otherwise needed spectrum -> cost saving
• Use of relays to extend the coverage of mmWave

Reconfigurable Intelligent Surfaces (RISs):

• Better planning: When placing new RAN nodes is difficult or costly
• Deployment cost: Accelerating the use of mmWave in a cost-effective manner
• Sustainability: Lowering energy consumption

More details are available in the following presentation and the references [8, 10 – 19]. Also, the presentation provides a tentative roadmap and timeline for 6G.

References:

• [1] What is 5G | Everything You Need to Know About 5G | 5G FAQ | Qualcomm
• [2] https://www.reply.com/en/industries/telco-and-media/5g-mastering-the-magic-triangle
• [3] https://www.youtube.com/watch?v=XvLDXsDLOeM&t=249s
• [4] https://www.3gpp.org/specifications/releases
• [5] Emilio Calvanese Strinati et al., “6G: The Next Frontier: From Holographic Messaging to Artificial Intelligence Using Subterahertz and Visible Light Communication”, IEEE Vehicular Technology Magazine (Volume: 14, Issue: 3, September 2019)
• [6] https://www.eucnc.eu/wp-content/uploads/2020/07/2020-05-29-6G.-Why-Nicolas-Demassieux-EUCNC-VDEF.pdf
• [7] https://5g-allstar.eu/wp-content/uploads/2020/09/2019-11-KeynoteEU-KR-Workshop-Beyond-5G-6G-Final-Presented.pdf
• [8] https://arxiv.org/pdf/2004.14247.pdf
• [9] https://www.mdpi.com/1424-8220/22/3/762
• [10] https://www.free6gtraining.com/2021/07/chinas-imt-2030-6g-promotion-group.html
• [11] https://newsletter.mediatek.com/hubfs/MediaTek-6G-Vision-White-Paper-EN0122.pdf?__hstc=153516580.8169bb5874d4122168dda966eefc3881.1663399788135.1663399788136.1663399788136.1&__hssc=153516580.2.1663399788138&__hsfp=483372179
• [12] https://www.youtube.com/watch?v=CxmV2IPGrDA
• [13] https://b5g-mints.eu/ris-blog6/
• [14] https://www.youtube.com/watch?v=-7WTZvS3PTw&t=2191s
• [15] https://cdn.codeground.org/nsr/downloads/researchareas/6G%20Vision.pdf
• [16] https://www.rimedolabs.com/blog/introduction-to-o-ran/
• [17] https://www.techplayon.com/open-ran-o-ran-reference-architecture/
• [18] https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8901159
• [19] https://www.6gworld.com/exclusives/experts-debate-whether-6g-will-see-the-use-of-terahertz/

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