Lending 5G-Advanced and 6G a Hand with Intelligent 'Super Surfaces'

Though 5G deployments are very much the flavour of today, some are already looking forward to the types of technology to deploy to support the next generations of mobile technology. Alex Wang, managing director for radio-access-network (RAN) solutions at ZTE, explains how reconfigurable intelligent surface (RIS) technology provides one answer for 5G-Advanced and 6G.
5G is just starting to take off in many countries worldwide, after early adopters started launching the technology in 2019. But while it still has plenty of growth ahead, some are looking even further into the future to pave the way towards the next mobile generation.
This next generation, 6G, is expected to arrive in around 2030, following the emergence in the middle of this decade of the ‘half-generation', 5G-Advanced. Mobile technologies will keep moving on, spurring those at the cutting edge to carry on planning ahead to ensure that the transition to the next stage of the journey is as smooth as possible.
As networks have densified to meet growing coverage and capacity needs, part of this is about finding fresh technologies that improve the efficiency of new mobile generations, and cut deployment costs and time. At the same time, it is essential to meet today's growing demand for greener, low-carbon networks.

Reconfigurable Tech

One up-and-coming technology that the industry believes can fulfil these requirements is known as reconfigurable intelligent surface (RIS), or metasurface. This aims to facilitate the dynamic control of radio signals between a transmitter and a receiver, thus boosting network coverage and signal penetration.
Alex Wang, managing director for RAN solutions at ZTE, explains that the technology can help overcome propagation challenges involving outdoor coverage and indoor penetration.
The technology uses so-called 'metasurfaces' that are electromagnetically controlled and can be installed at or attached to places such as lamp posts, walls or windows to help shape the wireless-propagation environment. A signal that hits the 'intelligent super-surface' can be formed into beams that precisely target different users' devices and help ensure seamless connectivity even during movement.
Wang says these capabilities have significant potential to improve the performance of technologies supporting 5G-Advanced and 6G. "RIS will tremendously enhance coverage for operators deploying those solutions," he says. "It's a marriage of mobile communications and materials technology. You can achieve different kinds of beamforming, with flexible and intelligent reflection."
He also cites different types of RIS—namely reflective RIS, which reflects radio signals off objects, and transmissive RIS, which can help signals penetrate deeper indoors.

Emerging Tech

ZTE unveiled its RIS proposition at the Mobile World Congress in Barcelona this March, envisaging the service as a core technology for underpinning 5G-Advanced and 6G. Having already begun research on RIS a few years ago, the vendor has been working with operators, universities, scientific research institutions and standardisation bodies to explore the concept.
It has run prototype tests with several operators that Wang says have worked well, verified the concept and received positive feedback. In outdoor tests that ZTE carried out in conjunction with millimetre-wave (mmWave) technology being used in 5G deployments, RIS both succeeded in boosting signal strength and also enhanced speeds by up to 50 times.
The improved coverage is important not just for cost reasons, but also because the power consumption of the technology is lower than for base stations, adds Wang. This, he says, allows the deployment of a greener network.
And he says operators are enthusiastic about the prospects for using the technology. "They are looking for more effective solutions, from reducing hardware costs to reducing power consumption and opex as well," he says. "So this is definitely one area that is worth continuing in pursuance of that."
He adds that operators are looking to find ways to enhance the performance of existing technologies. "Some operators are talking about how to further improve the performance of higher-frequency bands," says Wang.

Meeting Demand

With regard to this, he says ZTE is keen to put itself at the forefront of developments by pursuing innovations that match operator requirements, pointing to its previous efforts to take a lead on massive MIMO for Pre5G and 5G. "There is definitely a demand in the market from the operator side—and also, there is continuous innovation and technology evolution from our side," he says.
In addition, ZTE is a founder member of the RIS TECH Alliance (RISTA) established in Beijing four months ago, as an initiative to spur research into and growth of the new technology, as well as its standardisation. Wang points to the traction this alliance has gained to highlight the interest that RIS is generating, with around 100 members having already signed up to RISTA.
Though many challenges lie ahead in areas such as how best to deploy the technology as networks densify and standardise it for future use, Wang is positive about its prospects.
"RIS is a very promising technology for 6G, and we are also working actively to bring this technology forward into the 5G era with 5G-Advanced," he says. "We are working together with different partners to verify and make it a success. It's a long-term mission and we are moving step by step."