Rohde & Schwarz and Viyawei Communications jointly showcase a digital twin AI receiver test solution for communication channels

During MWC Shanghai 2026, Rohde & Schwarz (hereinafter referred to as ‘R&S’) and VIAVI Communications (hereinafter referred to as ‘VIAVI’) jointly demonstrated an AI-based receiver test solution utilising a digital twin of the transmission channel. The solution utilises the R&S SMW200A vector signal generator and FSW spectrum analyser, with deep integration of VIAVI’s ray-tracing channel software, to simulate real-world signal propagation environments. It verifies the performance gains and generalisability of AI receivers in a laboratory setting that replicates real-world physical conditions.

AI receivers are currently a leading candidate technology in the 3GPP 6G air interface standardisation process. The principle behind them is to utilise AI to optimise traditional receiver modules—such as channel estimation, equalisation and demodulation—thereby enhancing overall air interface performance. At present, there are two key challenges facing the R&D of AI receivers in the industry: Firstly, mainstream research relies on purely software-based simulation platforms; however, the simulated channel environments are overly idealised and fail to replicate real-world wireless link interference, making it impossible to accurately assess the receiver’s true performance under actual hardware test conditions; Secondly, the deployment process for field testing is cumbersome, environmental variables are difficult to control, and test repeatability is low, making it impossible to flexibly carry out iterative debugging of receiver parameters and standardised performance evaluations.

To address these industry challenges, R&S has partnered with VIAVI to leverage both companies’ strengths in hardware and software technology, jointly developing this AI receiver test solution based on a digital twin of the communication channel. The solution aims to effectively bridge the gap in hardware-level testing capabilities for 6G AI receivers, support preliminary research into cutting-edge technologies, and accelerate the large-scale industrial deployment of related technologies.

Figure 1: Framework for an AI-based receiver test solution utilising a channel digital twin

This test solution features a complete closed-loop signal chain: at the transmitter end, the SMW200A vector signal generator produces standard communication baseband signals, which are superimposed with VIAVI’s high-precision ray-tracing channel simulation model to output RF signals that closely match real-world propagation characteristics to the FSW signal and spectrum analyser at the receiver end; After the FSW at the receiving end has completed high-precision IQ raw signal acquisition, the raw IQ data stream can be transmitted back to the user’s in-house host software or to the R&S VSE vector signal analysis software for in-depth signal analysis and algorithm evaluation. The solution’s built-in AI receiver algorithm is developed entirely on the NVIDIA SIONNA communications simulation framework, ensuring high compatibility with the industry’s leading R&D ecosystems.

Figure 2: Interface of the AI receiver test software

The R&S flagship RF instruments featured in this solution fully meet high-performance testing requirements: The R&S SMW200A high-performance vector signal generator comes standard with a 2 GHz modulation bandwidth, supports RF output up to 67 GHz, and offers excellent signal purity and low distortion. It features a built-in native multi-channel MIMO channel fading simulation module, enabling the rapid generation of complex modulated signals and cutting-edge test waveforms for multiple standards such as 5G, Wi-Fi and automotive radar. It is widely used in the testing of RF chips and complete end-user devices. The FSW high-performance signal and spectrum analyser covers all mainstream 5G FR1/FR2 communication bands, featuring industry-leading low phase noise and ultra-high receiver sensitivity, with a real-time analysis bandwidth of up to 8.3 GHz. supporting real-time demodulation and in-depth analysis of 5G NR, radar and satellite communication signals. Equipped with high-precision algorithms, it combines high-speed measurement with a wide dynamic range, making it suitable for the detailed inspection of complex 6G RF and millimetre-wave signals.

VIAVI’s VMS5000 ray-tracing channel simulation software is a high-precision channel simulation tool designed for 4G/5G/6G network planning and optimisation. By simulating radio wave propagation as ray-like behaviour in a three-dimensional environment and modelling key propagation mechanisms such as reflection, diffraction and scattering, it predicts signal strength, coverage areas and potential dead zones. It accommodates the characteristics of different frequency bands, ranging from low to medium-high frequencies, and offers flexible output formats such as planar coverage heatmaps or channel information for selected locations, helping customers to design wireless networks more efficiently and address challenges such as signal obstruction and multipath effects in greater depth. Unlike traditional ray tracing tools, VIAVI’s ray tracing software supports mobility simulation, ISAC integrated sensing and communication, and incremental, continuous updates, whilst seamlessly integrating with platforms such as the TM500 terminal simulator and the Vertex fading channel simulator.

Li Yushan, Director of Wireless Business Development at VIAVI, stated: “ VIAVI’s Ray Tracing channel simulation software utilises GPU acceleration to achieve near-real-time simulation. It comprehensively models various propagation mechanisms—including direct propagation, reflection, diffraction, scattering and penetration—enabling the creation of high-fidelity digital twins of complex wireless scenarios in the laboratory. This allows for the precise reproduction of real air-interface environments under controlled and repeatable conditions, whilst flexibly balancing simulation accuracy with computational efficiency. This deep integration with R&S’s flagship RF instruments has further bridged the gap between ray-tracing channel simulation and the practical testing of AI algorithms; when combined with test platforms such as the VIAVI TM500, it enables per-UE-level channel modelling and network testing. As a key component of the TM500 Air Interface Digital Twin, this solution will help accelerate the transition of cutting-edge technologies to large-scale commercial deployment.”

Jin Hailiang, Senior Director of the Products and Systems Division at R&S Rohde & Schwarz, stated: “With the 6G standardisation process currently accelerating, AI receivers have become a key technological direction for the air interface; however, the industry has long lacked hardware-level verification solutions that closely replicate real-world propagation environments. We are delighted to have partnered with Weiyawei to develop this integrated channel digital twin test platform. By utilising the SMW200A and FSW flagship instruments to bridge the gap between ray-tracing channel simulation and practical AI algorithm testing, we have established a standardised practical testing framework for verifying the performance of 6G AI receivers. This integrated testbed can accurately replicate complex, real-world wireless scenarios and efficiently validate the generalisation capabilities of AI receivers. We look forward to further deepening industry collaboration, refining the 6G air interface AI testing framework, and facilitating the commercial deployment of next-generation mobile communication technologies."