New 6G challenges inspire cross-disciplinary innovation

Roger Nichols remembers sending his first e-mail using wireless networks in the early 1990s, from the back of a bus during his daily commute. That was 30 years ago, on a 1G network-at a data rate about fifteen thousand times slower than today.

Now the 6G program manager at Keysight Technologies, Nichols sees the rapid growth of the current mobile wireless standard and knows that there is much more to come. As of June 2022, the Global Mobile Suppliers Association counted nearly 500 operators in 145 countries that had deployed-or planned to deploy-5G capabilities, up from 412 at the end of 2020. Omdia and 5G Americas project that by the end of 2022, more than 1.3 billion connections will be made to global 5G networks.

The intervening decades have seen an explosion in the use of wireless data connections," he says. 5G systems will not only help with increasing demands for speed, latency, and reliability, but also with the flexibility required to make the most of the costly resources of modern networks: spectrum and energy."

But 5G is just the current stage in the evolution of mobile wireless networks. Today's dramatic growth in 5G availability is the continuation of a march toward advanced wireless capabilities, one that began more than four decades ago when Japan's NTT deployed the first automated mobile network. And even while this current generation of wireless connectivity is deployed, engineers and technologists are aiming to push the technology into its next generation, 6G.

It's clear that tomorrow's innovative applications will require still better connectivity. Augmented reality will allow workers to enhance their surroundings with detailed information or will connect consumers through virtual worlds. Networked devices that collect data from physical objects-from airplanes to tires to infrastructure-promise to deliver more intelligence to management systems. Connected vehicles will communicate with one another, improving driving efficiency and safety.

How 6G will be used is speculative," Nichols says; however, the list of 6G use cases varies from 5G-on-steroids' to what looks like science fiction."

New challenges for the next generation of wireless

To create 6G infrastructure, devices, and software, however, engineers and researchers will have to solve a plethora of problems. Aiming to improve mobile wireless connectivity by an order of magnitude presents challenges that can't be addressed by merely scaling existing technology. These include mastering the physics of high-frequency signals, managing space requirements within devices for multiple wireless chips and hardware, and developing the software needed to automate the management of distributed and programmable networks.

The coming 6G systems will add additional non-contiguous spectrum to an already complex spectrum map. They will also bring more sophisticated active-antenna systems, further integration into networks using other Radio Access Technologies (such as WLAN, Bluetooth, UWB, and Satellite), and joint communications and sensing technology. Integrating all of this into a single device, such as a smartphone, will demand a huge and complex variety of radio transceiver technology. This will require very creative electrical and computer engineering as well was disruptive industrial engineering and power management.

Computing power and data storage will be ever increasing challenges for the new high-speed and programmable communication networks. To accommodate exponentially growing populations of devices that need to access the 6G network, new chips will need to process signals more quickly, requiring more power and faster storage. Managing the sensors required to create detailed digital twins-simulations based on the collection of real-world data-also requires a great deal more processing power and fast storage space than is available on current networks.

Providing low latency (minimal delay) is already a familiar challenge for mobile networks, and one that will continue as next-generation applications increasingly allow interactive manipulation of data, responsive virtual environments, or real-time monitoring and management of remote systems. New 6G applications will layer on a need for extremely precise timing-absolute predictability of when data packets will be sent or received.

Bold research advances will underpin future connectivity

Addressing these physical and technical limitations will require leaps of innovation, but the promise of applications powered by advanced 6G connectivity is motivating creative solutions.

Adaptive technology solutions are a key area of research. Rather than focus on optimizing the bandwidth for a single device, for example, the 6G network will use nearby devices to help deliver the necessary bandwidth and reduce latency. This 3D signal shaping focuses on combining and processing wireless signals from multiple sources, based on their proximity to the end user.

New semiconductor materials will help manage device space requirements as well as handle wider frequency bands. Though it requires complex engineering, one promising approach combines traditional silicon circuits with those made from more exotic compound semiconductors, such as indium phosphide. In addition, researchers are looking at ways of changing the environment with reconfigurable intelligent surfaces (smart surfaces") that can optimize signal propagation to modify signals in real time to deliver better bandwidth and lower latency.

Another avenue of research relies on artificial intelligence to manage networks and optimize communications. Different types of network usage (texting, gaming, and streaming, for example) create different types of network demand. AI solutions enable a system to predict this demand based on behavioral patterns, instead of requiring engineers to always design for the highest demand levels.

Nichols sees great potential for networks from improvements in artificial intelligence. Today's systems are so complex, with so many levers to pull to address the diverse demands," says Nichols, that most decisions on optimizing are limited to first-order adjustments like more sites, updated radios, better backhaul, more efficient data gateways, and throttling certain users." By contrast, employing artificial intelligence to handle the optimization, he says, presents a significant opportunity for a move to autonomous, self-optimized, and self-organized networks."

Virtual simulations and digital-twin technology are promising tools that will not only will assist in 6G innovation but will be further enabled by 6G once established. These emerging technologies can help companies test their products and systems in a sandbox that simulates real-world conditions, allowing equipment makers and application developers to test concepts in complex environments and create early product prototypes for 6G networks.

While engineers and researchers have proposed innovative solutions, Nichols notes that building 6G networks will also require consensus between technology providers, operators, and carriers. While the rollout of 5G networks continues, industry players should create a cohesive vision for what applications the next-generation network will support and how their technologies will work together.

It is this collaboration and complexity, however, that may generate the most exciting and enduring outcomes. Nichols notes that the breadth of engineering specialties required to build 6G, and the industry collaboration necessary to launch it, will drive exciting cross-disciplinary innovation. Because of the resulting demand for new solutions, the path to 6G will be paved, in Nichols' words, with a tremendous amount of technical research, development, and innovation from electronics to semiconductors to antennas to radio network systems to internet protocols to artificial intelligence to cybersecurity."

This content was produced by Insights, the custom content arm of MIT Technology Review. It was not written by MIT Technology Review's editorial staff.