With the fast adoption of drones, robots, XR (extended reality), and other devices, signal processing for the next generation of connectivity known as 6G will be much more demanding than for fifth-generation mobile communication systems (5G). Japan’s National Institute of Information and Communications Technology (NICT) has developed a signal processing method able to cope with the expected high device density in the 6G era.
The method involves a combination of quantum computing and traditional computing. NICT has successfully demonstrated the efficiency of the method through outdoor experiments, handling 10 devices simultaneously under the anticipated massive 6G connectivity requirements.
The result represents a significant step toward realizing large-scale machine-to-machine communications in future 6G networks, including applications involving drones, robots, and XR devices.
Exponential growth in complexity
Compared with 5G systems, device density in 6G networks is anticipated to increase by more than an order of magnitude. A promising technology addressing this challenge is non-orthogonal multiple access (NOMA), which enables multiple devices to transmit simultaneously over the same time and frequency resources.
In such scenarios, signals from multiple devices are superposed at a base station and must be individually detected. With more devices added, the number of signal combinations grows exponentially. Consequently, the computational complexity grows rapidly with the number of connected devices, potentially leading to large processing latency and making real-time detection difficult.
To address this challenge, NICT has developed a new hybrid signal processing method that integrates a quantum annealing machine (a type of quantum computer) with a classical computer. The method is applicable to multi-antenna and multi-carrier transmission.
Error-free signal detection
The proposed method was implemented at a base station in a wireless communication experimental system, and outdoor over-the-air experiments were conducted, involving up to 10 devices simultaneously. Two different quantum computing approaches – Simulated Quantum Annealing (SQA) and Linear Minimum Mean Square Error (LMMSE), respectively – were applied. The experiments demonstrated error-free signal detection for both annealing methods.
The results demonstrate that the proposed hybrid signal processing method can effectively support the massive connectivity expected in the 6G era, corresponding to a tenfold increase in device density compared with 5G systems.
Source: “Demonstration of massive connectivity for the 6G era – Successful simultaneous communications using a quantum computer”, Press Release, NICT.
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