Technology Advances the Need for 6G

Welcome to the third installment of our blog series on 6G technology. This series explores the expectations from 6G as it shapes enterprises, networks, and society, as we approach the definition stage of defining the fundamental technologies that will form the global network of the 2030s and beyond.

As I discussed in the first blog of the series, the majority of the technologies being introduced are enhancements or existing technologies, and those in line to become available in Release 17/18 onwards. However, that's just one facet of the picture. We're currently at the genesis of the vision for IMT-2030, otherwise known as 6G networks with numerous research bodies investigating the path forward. Recently, my podcast co-host, Allie Irvin, and I welcomed Dr. Peter Marshall, Strategic Marketing Director at Ericsson, to discuss the vision of 6G technology.

In this blog, I will look past the use cases and aspirations, and examine some of the technologies that will be necessary to make this vision a reality. Additionally, I will explore the key technological advancements that will pave the way for 6G networks and the IMT-2030 vision. Building upon the achievements of 5G, 6G is expected to revolutionize the way we connect, communicate, and interact. Let's explore the essential technology changes that will make 6G a reality. My previous blogs focused on the outcomes of creating an immersive, intelligent, and ubiquitous networks. The real challenge, however, lies in developing the exploitable technology to integrate into these networks.

Technology Advances

Spectrum and Radio Efficiency

6G's higher frequencies will facilitate faster sampling rates compared to 5G. They will also provide significantly escalated throughput and higher data rates. Employing sub-mm waves - wavelengths less than 1 millimeter - and frequency selectivity to determine relative electromagnetic absorption rates are projected to advance the development of wireless sensing technology.

One of the defining characteristics of 6G is the utilization of higher frequencies and improved spectrum efficiency. By exploring millimeter wave and terahertz communications, researchers are seeking ways to surpass the limitations of lower frequency bands. These strides will facilitate higher data rates, increased network capacity, and improved spectral efficiency. With 6G, we can expect lightning-fast downloads, seamless streaming, and ultra-responsive applications that will transform our wireless connectivity experience. Numerous reviews are available on the application of Terahertz communications, such as “Terahertz Communications: Challenges and Impact on 6G Wireless Systems," Which focus on the feasibility and challenges of terahertz communications in future wireless networks.

For some people, it might seem like I am just discussing another radio frequency. However, THz presents a whole new world of opportunities, offering an exponentially larger usable spectrum than currently available, irrespective of regulations. Terahertz waves, or THz waves, are a type of electromagnetic wave that spans a broad spectrum ranging from 0.1 to 10 THz. They have a wavelength that varies between 30 to 3000 microns. As they straddle the gap between macro-electronics and micro-photonics, THz waves reside in the transitional zone between microwave and infrared light. While the frequency band for THz communication is not fully developed, it possesses several beneficial traits that make it highly valuable for the future of mobile communications.

THz waves bring with them a wealth of spectrum resources, impressive transmission speeds, and a generous bandwidth reaching up to 10 THz. THz waves also have the ability to penetrate objects that aren't transparent to the naked eye. Additionally, they enable interactions with micro-scale objects, such as nanonetworks, using scaled-down antennas with a wavelength of approximately 1 mm for 300 GHz. As illustrated in Figure 1, the scaling from earlier generations of mobile communications will be greatly enhanced getting to 6G, with the networks of 2030 encompassing mmWaves, THz, and VLC visible light communication (VLC) bands.

Figure 1 - Spectrum and Generations of Cellular

Cell Free Massive MIMO and Beamforming

Massive MIMO (Multiple-Input Multiple-Output) and beamforming are key technologies that will continue to evolve within the realm of 6G. These techniques bolster spectral efficiency and provide superior coverage and capacity. With massive MIMO, wireless networks can support an unprecedented number of simultaneous connections, resulting in enhanced speeds and decreased network congestion. Beamforming allows for highly targeted and directed communication, resulting in improved signal quality and more effective utilization of network resources.

One a significant advancement for 6G networks will be the widespread application of cell free massive MIMO (CF-mMIMO). This addresses the bottleneck in cellular communications networks caused by intercellular handover interference. Intercell interference is an essential component of handover between single and multi-array cells.

Figure 2, inspired from the article, ubiquitous cell-free massive MIMO communications, illustrates (from top right) the evolution from user-equipment (UE) attaching to a single cell, to a state where cells cooperate to ensure connectivity, and then to clusters associated with the nearest cell to provide multiple signals. Within these networks, the fronthaul from the Radio to the CPU manages capacity requirements and access based on the maximum bandwidth across all networks for each user. Envision a future that will take advantage of intelligent networking to implement a user-centric, cell-free network. From the user device perspective, the term "cell-free" suggests that the cell boundaries do not govern the connectivity during a downlink session, resulting in increased bandwidth and spectral efficiency.

Figure 2 – Cell free massive MIMO

Beamforming is a technique that employs an antenna array to transmit and receive signals with a focused, high-gain narrow beam. By concentrating the power within a specific angular range, beamforming enhances coverage, throughput, and the signal-to-interference-plus-noise ratio (SINR). In the context of 6G, a more advanced form of beamforming known as hybrid beamforming (HBF), is gaining prominence. HBF utilizes a software-defined antenna where RF signals from the radio are directed to an optical hologram located at the antenna’s rear, known as a holographic plate. This allows for precise adjustments of the beam's shape and direction, accommodating these minute components. HBF's use enables flexible and efficient sharing of radio frequencies among 6G systems and IoT devices. Additionally, HBF significantly enhances position accuracy in 6G networks and IoT applications, achieving centimeter-level precision.

Both of these technologies will complement the improvements in radio technology necessary to achieve terabit communication to user devices, necessary for high bandwidth user applications, such as eXtended reality (XR).

Networking Architecture Advances

5G Network architectures have already integrated cloud native concepts like service-based architecture to simplify the network design and prioritize open and software-based systems. 6G networks progress this evolution further, creating significantly more potential applications than current mobile edge technologies, such as multi-access edge computing (MEC). The most significant and essential concept here will be the idea of computing in the network, or computer in the network (COIN), technologies which will complement cell-free solutions described previously mentioned.

Initially conceived as a compute fabric across the entire network, COINprovides a unified and pervasive compute system across an entire network ecosystem. The future designers, operators and users of 6G networks will employ intelligent processing nearer to the data source, enabling distributed decision-making throughout the network.

The final architectural concept necessary to enable achieve the ambitious speed, low latency, and responsiveness associated with 6G networks will be ultra-dense networks (UDNs). If we think of cell towers today expanding into denser environments such as busy streets, UDNs take this to the next level and deploy small cells everywhere. The objective is to accommodate every device –potentially up to fifty 6G connected devices per person – which will necessitate networks to surpass traditional benchmarks intended for normal human footfall. These devices will require a plethora of different demands, and every single device has to be mobile and sustainably efficient across all private and public domains. This will require the entire network to function as a heterogeneous network, integrating cellular and Wi-Fi seamlessly, powered by AI-driven management, real-time optimization, and game theory principles to optimize resource allocation while ensuring ubiquitous and reliable connectivity.                                             

Enhanced Energy Efficiency

Energy efficiency is a critical aspect in the development of future wireless networks, especially as we venture into the realm of 6G. Fundamentally, 6G seeks to drastically improve energy efficiency to meet the growing demand for sustainable and eco-friendly communication systems. However, this goal might not be as straightforward as envisioned – denser, high frequency networks require power.

From an efficiency standpoint, the idea of increasing the power levels of base stations in 6G networks to decrease the need for extra stations might seem advantageous theoretically. In reality, it raises practical issues, such as the decoupling of shared resources and regulatory limitations on electromagnetic radiation exposure. 6G networks are introducing valuable technologies like massive MIMO that expand network coverage without increasing power consumption per base station. And while 6G promises higher data throughput, the question is whether these high-speed connections should be universally available all the time, given power consumption and bandwidth needs. Striking a balance between efficiency with performance is a critical facet of wireless network design, and how these considerations are addressed will guide the optimal approach for 6G technology.

Fortunately, alongside network advancements, efforts are already underway to develop energy-efficient devices, including zero energy devices (ZEDs) described in a previous blog post. However, we'll need to push the boundaries even further. Cooperative research centers, like IMEC, are working on efficient power amplifiers, as discussed in this IEEE article. While network design and targets can only deliver so much, it's evident that this domain will garner more attention as the planet continues to experience climate change.

AI and Machine Learning

Artificial intelligence (AI) consistently captures attention as a key technology, and projections for 6G are no different. In fact, it's anticipated that AI will revolutionize wireless networks ( a claim made by the ITU, not me). However, the technologies that comprise AI will be crucial in optimizing network operations, enabling smart resource management, and enhancing overall system performance. With the power of AI and emerging hyper-models, 6G networks can aim for autonomous network management, intelligent decision-making, and efficient utilization of network resources. There are countless papers, subject to constant evolution, that explore how this will unfold, but at their heart, they all point towards a comprehensive, intelligent network that can autonomously optimize itself.

One emerging technology, intent-based networking (IBN), stands out as a promising answer to the efficiency, flexibility, and security challenges that traditional wireless networks face in the scope of sixth-generation technology. This network type, powered by AI, is integral to designing AI-enabled 6G networks, as it efficiently translates users' business intentions into strategies for network configuration, operation, and maintenance. Excelling at adapting to dynamic network environments and meeting the needs of large-scale, intelligent services, IBNs continually learn and adjust based on real-time network data. This allows them to navigate the challenges brought about by fluctuating radio propagation. Such a capability empowers IBNs to harness the wealth of collected network data to deliver optimal performance, by translating business intentions into various AI models. This drives the next iteration of software-defined networking, with the aforementioned tenets working together as below.

Such a capability empowers IBNs to harness the wealth of collected network data, delivering optimal performance by translating business intentions into various AI models. This drives the next iteration of software-defined networking, with the tenets mentioned earlier collaborating as illustrated in Figure 3.

Figure 3- Intent Based Networking (IBN)

There are a number of divergent forecasts on how this will manifest itself, trying to position IBN as somewhere between next generations management and orchestration (MANO) services, and others having it as an extension the computer in the network concept, with AI permeating the network. Most likely, as we move beyond 3GPP Release 20, these technologies will likely merge into a unified operating system, digital twin network platform, and a convergence service platform, exemplifying IBNs' capabilities.

Tactile Internet and Haptic Communication

6G envisions the realization of the Tactile Internet, enabling real-time haptic communication and remote physical interactions. This technology will unlock ground breaking applications such as remote surgery, immersive virtual reality, and augmented reality – although the vision of 6G (and 7G) make these advancements seem almost ordinary in comparison. To support a tactile and sensitive Internet, 6G networks will go beyond the requirements of ultra-low latency, high reliability, and advanced haptic feedback mechanisms, bringing human-machine interactions unprecedented heights. The necessity of interaction between new sense-enabled hardware and processes of transmitting, replicating, and understanding these interactions has been a research topic since the emergence of the first haptic devices. This field gained mainstream traction with the advent of haptic touch screen feedback in mobile phone technology. This concept of an Internet of Senses and vision of cyber-physical systems goes even further.

The fusion of enhanced sensory capabilities and previously niche mind-reading research has opened new possibilities. Neuromodulation, which involves intentionally modifying nerve activity using electrical or chemical stimuli, has seen advancements. Building upon this concept, we've seen the emergence of digital tasting applications and electronic noses, all designed to emulate the sensory experiences of taste and smell within a virtual environment. A real-time example of how wireless technology is shrinking in practical use is the closed-loop wireless monitor surgical implants as described in science advances, where ECG signals can be continuously monitored, and local stimulation provided and recorded, all  from a millimeter size device.

Figure 4 - Wireless Combined ECG & Heart Stimulator Prototype

The technology needed by 2030 goes far beyond mere signal replication. It will involve all senses, encompassing taste, touch, smell, sight, sound, and even cognitive processes that require chemical and electrical signals. By integrating our knowledge of the senses and applying neuroscience to advancements in electronics and microprocessor design, we now have the capability to stimulate sensations that were previously unreachable. The practical applications of the Internet of Senses move formerly conceptual research ideas into a tangible reality. This technology will showcase the true potential of these ideas, which are now being transformed into real-world experiences. The potential to evoke sensory perceptions digitally opens a multitude of possibilities, revolutionizing the way we interact with technology and expanding the frontiers of human experiences.

Other Technologies

Quantum Communications and Cryptography

Quantum communications and quantum cryptography will play a vital role in ensuring the security and privacy of 6G networks. Quantum key distribution (QKD) provides impenetrable encryption based on the principles of quantum mechanics. With quantum communications, 6G can achieve secure and tamper-proof data transmission, safeguarding sensitive information. It is worthwhile noting that QKD requires long-distance quantum effects to function, necessitating a satellite-based network to be feasible. However, early research indicates its potential value in securing pubic networks between nations.

Integrated Satellite and Terrestrial Networks

Integration of satellite and terrestrial networks will be a crucial aspect of 6G, ensuring global coverage and seamless connectivity across geographic regions. By combining the strengths of both satellite and terrestrial systems, 6G will provide ubiquitous and reliable connectivity, especially in remote and underserved regions. This integration will enable a wide range of applications and bridge the digital divide. The proliferation of low earth orbit satellites has brought non-terrestrial networks into prominence, and it remains to be seen whether this is a permanent trend. I plan to delve into this topic in more detail in an upcoming blog post, which won't be 6G-specific.

Summary

In this blog post, we have explored the technological advances that will drive the development of 6G networks, also known as IMT-2030. From higher frequencies and spectrum efficiency to AI and machine learning, each technology presents unique opportunities and challenges for the future of wireless communication. By harnessing these advancements, 6G aspires to deliver unprecedented data rates, ultra-low latency, and seamless connectivity, catalyzing a revolution in diverse industries and transforming the way we live, work, and interact. However, no single technology will be enough to realize the vision of 6G – every aspect of society will need to innovate and collaborate to get the best and make this an epoch-changing advancement, rather than marketing hype.

As we look ahead, it's important to recognize the valuable contributions of research and academic papers in charting the course for 6G's future The referenced papers provide further insights and in-depth analysis on the specific technological domains discussed in this blog post. By engaging with these papers, we deepen our understanding of the research landscape and the progress being made towards the realization of 6G. Yet, these are just the first steps in the journey towards harnessing all technologies needed to create the world of 2030. In my next blog, I will discuss the societal implications of this technology, and assess our readiness to embrace the big data and AI integral to propelling most of these advances.