6G • RAN
Beyond Diagonal RIS (BD-RIS)
Inter-Connected Element Matrix Reconfigurable Intelligent Surface
Next-generation metasurface where scattering elements are interconnected through reconfigurable circuit networks, unlocking theoretical maximum beamforming.
Technical Explanation
Classical RIS architectures assume each meta-atom element acts independently, represented mathematically by a diagonal scattering matrix. Beyond Diagonal RIS (BD-RIS) introduces reconfigurable impedance networks that physically interconnect neighboring elements. This non-diagonal scattering matrix allows energy to flow dynamically across the entire surface aperture, providing vastly superior beam-shaping flexibility, wider coverage angles, and up to 6 dB higher signal-to-noise ratio gains.
Key Functions
- Interconnects metasurface elements via reconfigurable impedance circuits
- Achieves non-diagonal scattering matrices for full-wave manipulation
- Delivers up to 6 dB higher beamforming gain than conventional diagonal RIS
- Overcomes extreme path loss in complex non-line-of-sight urban canyons
Specifications
IEEE Trans. Wireless Communications BD-RIS, ETSI RIS Work Item 003
Interfaces
BD-RIS Matrix ControllerOpen Front-Haul RIS Extension
Related 6G Concepts
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