A wireless network made up of 256 antennas has shown that it can coordinate signals and process data in real time. Built by researchers at Lund University's engineering faculty in Sweden, the system is designed to test technologies that may one day support 6G networks.
The platform, called the Lund University Large Intelligent Surface, or LuLIS, is not itself a complete 6G network. Instead, it gives researchers a realistic environment in which to study how a large number of antennas can work together. The team says it is the first real-time test bed to combine 256 digitally beamformed antennas distributed across different locations.
This matters because wireless networks face two competing pressures. Demand for data continues to rise as more people, vehicles, machines, and public services become connected. Yet the radio spectrum used to carry wireless signals is limited. Future networks will therefore need to serve more users without simply relying on more frequencies.
One possible answer is massive MIMO, a technology that uses many antennas at the same time. By coordinating them carefully, a network can direct signals toward different users and separate several data streams sharing the same frequency band. Massive MIMO already plays an important role in 5G. Researchers are now exploring larger and more distributed versions for future networks.
LuLIS consists of 16 programmable panels, each containing 16 antennas. Both the antennas and the computing work are spread across the panels. Data is processed in real time, making the setup closer to the conditions a working network would face.
Its modular design is another important feature. Researchers can add panels or place them in different locations without redesigning the entire system. Because much of the setup is controlled by software, they can also change how data is transmitted without replacing the hardware.
Building the system revealed problems that might be missed in theoretical research. Antennas in different places must remain precisely synchronized so that their signals support rather than interfere with one another. The computing work must also be divided efficiently among the panels. The team says it identified and solved several practical issues in both areas.
LuLIS builds on an earlier Lund University system called LuMaMi. That test bed demonstrated that massive MIMO could work outside theory and distinguished among 22 users transmitting in the same frequency band. According to the university, the result still holds a record for spectral efficiency, which measures how much information can be carried through a limited amount of spectrum.
The new system is designed to go further. Initial experiments reported in the research paper used four single-antenna user devices communicating with configurations of 64, 128, and 256 antennas. The researchers expect the expanded setup to support 32 users in the near future. Their longer-term goal is to increase the earlier spectral-efficiency record tenfold by adding more capacity to the test bed.
That goal has not yet been achieved, and 6G standards are still under development. For now, the significance of LuLIS lies in demonstrating that hundreds of distributed antennas and their calculations can be coordinated in real time. It turns an idea for future wireless networks into something engineers can test, measure, and improve.