PARTNER FEATURE: Thailand-based AIS partnered with ZTE to trial the vendor’s dynamic Reconfigurable Intelligent Surface (RIS) technology on the operator’s mmWave network in Bangkok, with the pair claiming a world first demonstrating improved network performance with lower power usage.
RIS is a multi-antenna technology using electromagnetic hyper-materials to extend base station coverage by intelligently reflecting or transmitting base station signals, and is said to be one of the most significant components of 5G-Advanced.
In July, ZTE introduced the second generation of RIS using dynamic functionality to incorporate beam sweeping and user tracking to increase the coverage range of base stations and improve performance, even when the user is on the move. The technology features programmable phase control components to enhance signal propagation, direction regulation and interference suppression in wireless communication.
ZTE managing director for 5G RAN solutions Alex Wang highlighted RIS 2.0 can reduce energy consumption at sites by up to 30 per cent, and is designed for easy installation and diverse environments.
In a statement, ZTE said the deployment in Thailand, the first dynamic RIS trial on a mmWave network, “explores new possibilities”, offering a low-cost, low-carbon solution using the spectrum at scale.
Tapping 400MHz of mmWave spectrum, the trial demonstrated “substantial enhancement” in signal coverage, with AIS customers able to consistently maintain a peak downlink rate of more than 1.6Gb/s and an uplink peak rate of about 260Mb/s, while moving within an office area larger than 400 square metres.
The rates are more than three times those achieved without RIS under obstructed circumstances, the company said.
Achieving similar peak data rates is relatively easy for other operators to replicate, Wang argued, but noted the increase depends on the coverage conditions without RIS. “If the original coverage was poor, it is possible to achieve an increase of even more than three times. On the other hand, if the coverage was already good, the improvement may not be as significant.”
ZTE emphasised the trial with AIS is an important milestone for mmWave communication, “signifying a significant stride in the commercialisation of dynamic RIS technology, with the implementation leading to “revolutionary changes to the global communication industry, establishing a stronger network foundation for the development of future smart cities, industrial IoT and other domains”, the statement added.
Wasit Wattanasap, head of nationwide operations and support business at AIS, stated it believes RIS can accelerate the arrival of the 5G-Advanced era and deliver unprecedented communication experiences to users.
While mmWave spectrum is a crucial frequency range in 5G networks, offering large bandwidth and capacity, due to its transmission characteristics it encounters significant challenges in terms of long-distance transmission and penetration through obstacles. ZTE’s RIS 2.0 effectively overcomes propagation obstacles to increase the coverage range and transmission speeds.
Wang told Mobile World Live the key advantages of dynamic RIS over static are improvements in coverage, performance and ease of deployment. He added RIS also is a promising technology for 6G.
Wider coverage is made possible primarily using a large-scale antenna array. “The more antenna elements, the greater the gain. However, this also leads to a narrower beam, resulting in a smaller coverage area. When users move, it is easy to go out of the coverage range with static RIS. Dynamic RIS solves this problem by supporting RIS beam sweeping,” Wang explained.
The technology supports beam user tracking, which ensures an optimal user experience when a subscriber is on the move by pointing in real time to the beam with the strongest signal at the user’s device.
With static RIS, a beam cannot be adjusted after it is made, which means for each different environment a specific RIS needs to be customised and manufactured. In addition, manual adjustment of the RIS direction is required during deployment, making the process challenging to commercialise on a large scale.
Dynamic RIS supports beam sweeping and user tracking through software programming, enabling it to adapt to different environments without the need for customisation. After deployment, beams will automatically adjust, eliminating the need for manual network optimisation.
ZTE is focusing on the 26GHz and 28GHz bands, as well as sub-6GHz airwaves, such as 4.9GHz, as these higher frequency bands often have relatively poor coverage, making RIS particularly valuable.
Wang noted the potential savings in a deployment depends on the spectrum band used.
ZTE and China’s three major mobile operators in 2021 completed the first stage of static RIS verification and explored the feasibility of using technology to improve fixed-point coverage in 5G blind spots and other weak areas.
Last year, ZTE and the China Mobile Research Institute completed the first technical verification tests of a dynamic RIS prototype equipped with collaborative beamforming capabilities in the lab and in the field.
ZTE is a founding member of the RIS Tech Alliance established in Beijing in 2022.
China Telecom’s Zhejiang branch worked with ZTE to deploy dynamic RIS at the site of the Asian Games, which opened in mid-September in Hangzhou. The head of China Telecom’s team managing the event network said RIS has the potential to increase coverage areas by more than 30 per cent by intelligently reflecting or transmitting base station signals.
Verification tests showed after RIS was deployed, the downlink rate increased six times and the uplink rate by 20 times, with the cost one-tenth of that of small cells.
During the Asian Games, China Mobile Research Institute, Zhejiang Mobile and ZTE also jointly completed live service application of dynamic RIS at the cycling stadium, which significantly improved signal coverage quality and user speeds. ZTE noted this effectively met the high-capacity service demands of the stadium and provided excellent network support, ensuring a high-quality user experience.
While many operators, equipment vendors and research institutions are conducting related research and development, Wang believes in terms of product maturity, performance and extensive validation, ZTE is currently the industry leader in the field of RIS.
Rolling out RIS in a network environment involves selecting the deployment locations, choosing the specifications, deploying and enabling RIS, and then optimising the network. The first two steps can be achieved using the company’s automated tools, while optimisation doesn’t require manual intervention due to the dynamic RIS beam environment adaptability, Wang stated.
“The entire deployment process can typically be completed in a couple of hours.”
In addition to China and Thailand, he noted ZTE is targeting all markets with mmWave network deployments.