Mobile operators are speeding up the deployment of 5G, a flexible, low-latency, multi-gigabit-per-second communications network. Not only will the technology provide quicker data speeds, but it will also make the network more adaptable and programmable. This will be combined with the high reliability and low latency required to build secure, dependable wireless ecosystems that will benefit businesses other than traditional smartphone use-models, such as manufacturing, transportation, and healthcare.
As many of us are just becoming familiar with the benefits of 5G, technology and communications companies are looking ahead to the next generation, 6G. Although the actual job description of 6G is still being written, the hopes for the technology are to enable a pervasive, seamless internet of things that connects not only people's devices to the network, but allows sensors, vehicles, and many other products and technologies to communicate with each other seamlessly and reliably. For example, having vehicles that can not only communicate to the cloud, but to each other will result in more efficient traffic and safer travel, proponents say.
"6G is not defined, so a great degree of flexibility is needed to help companies navigate potential changes of direction," says Greg Jue, a 6G system engineer at Keysight Technologies, a testbed provider for advanced technologies. "They require flexibility in being able to change the product, shift development, and then be able to test the new platform."
The differences between 5G and 6G are not just about what collection of bandwidths will make up 6G in the future and how users will connect to the network, but also about the intelligence built into the network and devices. “The collection of networks that will create the fabric of 6G must work differently for an augmented reality (AR) headset than for an e-mail client on a mobile device,” says Shahriar Shahramian, a research lead with Nokia Bell Laboratories. “Communications providers need to solve a plethora of technical challenges to make a variety of networks based on different technologies work seamlessly,” he says. Devices will have to jump between different frequencies, adjust data rates, and adapt to the needs of the specific application, which could be running locally, on the edge of the cloud, or on a public service.
"One of the complexities of 6G will be, how do we bring the different wireless technologies together so they can hand off to each other, and work together really well, without the end user even knowing about it," Shahramian says. "That handoff is the difficult part."
Although the current 5G network allows consumers to experience more seamless handoffs as devices move through different networks—delivering higher bandwidth and lower latency—6G will also usher in a self-aware network capable of supporting and facilitating emerging technologies that are struggling for a foothold today—virtual reality and augmented reality technologies, for example, and self-driving cars. Artificial intelligence and machine learning technology, which will be integrated into 5G as that standard evolves into 5G-Advanced, will be architected into 6G from the beginning to simplify technical tasks, such as optimizing radio signals and efficiently scheduling data traffic.
“Eventually these [technologies] could give radios the ability to learn from one other and their environments," two Nokia researchers wrote in a post on the future of AI and ML in communications networks. "Rather than engineers telling … nodes of the network how they can communicate, those nodes could determine for themselves—choosing from millions of possible configurations—the best possible to way to communicate."
Testing technology that doesn’t yet exist
Although this technology is still nascent, it is complex, so it’s clear that testing will play a critical role in the process. “The companies creating the testbeds for 6G must contend with the simple fact that 6G is an aspirational goal, and not yet a real-world specification,” says Jue. He continues, “The network complexity needed to fulfill the 6G vision will require iterative and comprehensive testing of all aspects of the ecosystem; but because 6G is a nascent network concept, the tools and technology to get there need to be adaptable and flexible.”
Even determining which bandwidths will be used and for what application will require a great deal of research. Second- and third-generation cellular networks used low- and mid-ranged wireless bands, with frequencies up to 2.6GHz. The next generation, 4G, extended that to 6Ghz, while the current technology, 5G, goes even further, adding so-called “mmWave” (millimeter wave) up to 71GHz.
To power the necessary bandwidth requirements of 6G, Nokia and Keysight are partnering to investigate the sub-terahertz spectrum for communication, which raises new technical issues. Typically, the higher the frequency of the cellular spectrum, the wider the available contiguous bandwidths, and hence the greater the data rate; but this comes at the cost of decreased range for a particular strength of signal. Low-power wi-fi networks using the 2.6Ghz and 5Ghz bands, for example, have a range in tens of meters, but cellular networks using 800Mhz and 1.9Ghz, have ranges in kilometers. The addition of 24-71GHz in 5G means that associated cells are even smaller (tens to hundreds of meters). And for bands above 100GHz, the challenges are even more significant.
(This is a slightly modified version of an article originally published in Technology Review. The original article can be found at https://www.technologyreview.com/2022/04/21/1049824/flexibility-is-key-when-navigating-the-future-of-6g/)