The Next Horizon: Introducing the New Elements of 6G

6G will completely redefine what we know as possible, though this will also pose challenging requirements, which were discussed in previous posts of this series. And even though it seems like we are fresh off the buzz generated by 5G, 6G is not eons away.

When this technology arrives, it will encompass innovations ranging from new spectrum to new materials and antennas, new channels, and new devices — collectively referred to as the new elements.

In this post, I briefly cover the connotations of these new elements, along with some of the opportunities and challenges they create.

Read the previous posts in the series here: 6G: The Next Horizon.

Enter new spectrum

In line with the trend set by previous iterations of wireless transmission technologies, 6G will explore even higher frequency bands — think the sub-THz spectrum. This will happen within a multi-layered framework that also takes advantage of low- (700–900 MHz) and mid- (3–5 GHz) bands to make wide coverage possible.

Low- and mid-bands

In this framework, the low- and mid-bands will remain the most-cost effective way of achieving wide coverage, but we will also need an additional 1–1.5 GHz of mid-band spectrum to support increased traffic. In this regard, compared with 3.5 GHz, 6 GHz and 10 GHz will keep propagation attenuation within an acceptable range and reduce path loss through more advanced technologies.

mmWave advances

The mmWave bands are more challenging due to severe radio propagation. Nonetheless, these bands will mature when 6G enters the scene. This is because more bandwidth will be required to support high data rates and achieve the centimeter-level sensing resolution needed for mapping with network infrastructures.

Also, as innovative radio technologies such as integrated access and backhaul (IAB) continue evolving, we will witness more efficient utilization of the mmWave bands.

Boundless possibilities for sensing and communication

With 230 GHz of spectrum allocated to mobile services in the THz range of 100–400 GHz, high data rates will be supported over short- and mid-distance communication. Additionally, various applications will be possible due to the ultra-wide bandwidth and shorter wavelengths of the THz bands.

To put this into perspective, just imagine using your smartphone to augment human senses, or put differently, to count the calories in your food and monitor your vascular health.

Enter new materials and antennas

Recent leaps in digital communication would not be possible without our achievements in semiconductor technologies, which will continue evolving as 6G sets the stage for new spectrum and antennas.

Progress towards THz silicon

Silicon technologies are popular due to their inherent advantages:

1. Low cost
2. High yield
3. Small geometry
4. Low power

One such technology is the SiGe-BiCMOS platform, which already performs imaging, spectroscopy, and communication at the same time.

As for the near future, estimates indicate that transistors will reach or even exceed 1 THz, meaning THz integrated circuits (ICs) will become a reality. That said, efficient and low-loss THz antennas are difficult to design and implement.

Reconfigurable materials and intelligent surfaces

Another aspect worth exploring is the electrical properties of materials. By tuning these properties, we can make more functional devices at a smaller form factor and reduced cost. We can create reconfigurable intelligent surfaces (RISs), which can then be used to extend coverage from indoor base stations to users, regular vehicles, or automatic guided vehicles (AGVs), with no direct links or even in the presence of obstacles.

Enter new channels

Naturally, challenges such as higher computational complexity will arise as we make progress. For this reason, we need to gear 6G channel modeling towards specific usage scenarios or seek a scheme that balances complexity and accuracy. There are three main examples and challenges:

1. New Spectrum

As we explore the THz bands, we will encounter increased free space path loss. To compensate for this, we need more advanced beamforming technologies; otherwise, we have to deal with a limited applied range.

2. New Antennas

Structures such as extremely large aperture arrays (ELAAs), RISs, and orbital angular momentum will have a lasting impact on channel modeling and performance evaluation. Specifically, ELAAs will bring new channel features that need characterization, and we will need to determine the beneficial application scenarios of RISs based on scattered models — such as cross-polarization rates, incidence-angle-dependent phase shifters, and non-ideal impairments.

3. New Scenarios

Scenarios such as integrated sensing and communication (ISC) heavily rely on surrounding environments, and as such, deterministic models related to specific geographical areas are preferred. As for non-terrestrial network (NTN) scenarios with satellites, we must consider the upper atmosphere and clutter loss in the propagation model, and develop new channel models for drones that serve as moving base stations.

Enter new devices

The next revolution in mobile devices will kick off when 6G materializes. Backed by the 6G communications system, future devices will be equipped with a new range of functions, and transform from “intelligent assistants connecting the physical and cyber worlds” to “hyper terminals in converged physical and cyber worlds”. In turn, these functions will set four major trends into motion.

1. Smarter devices

Mobile devices will implement AI and ML capabilities while also offloading computationally intensive tasks to edge clouds. Put differently, as AI and ML advance and short-range 6G communication technologies take shape, our devices will simply become more intelligent.

2. Versatile devices

As devices become more intelligent, we will push the boundaries of our current imagination even further. Take cyborgs for example. This concept will exist beyond the realm of sci-fi movies as humans integrate with devices that feature multi-sensory capabilities.

3. Diversified devices

This refers to how a wide range of human-centric and industrial devices will emerge, acting as sensors and actuators. As this happens, higher requirements will be posed on interconnectivity and anchor devices will create a seamless and consistent user experience.

4. Cloudified devices

Virtual devices will exist alongside physical ones, enabling privacy protection and creating new business models. Additionally, each 6G device will have a proxy — or virtual counterpart — in the cloud, allowing us to access all kinds of services on demand (and without geographical limitations) via shared devices.

With these new elements, the possibilities of 6G are endless. But we are also bound to make progress on many other fronts. Take interfaces for example, which are worth exploring in their own right. One day, we will be able to use implanted neurochips to communicate directly with our devices within an ecosystem backed by the new elements of 6G. When this day arrives, we will truly move from connected people and things to connected intelligence.

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Disclaimer: Any views and/or opinions expressed in this post by individual authors or contributors are their personal views and/or opinions and do not necessarily reflect the views and/or opinions of Huawei Technologies.