6G • RAN
Spherical Wavefront Pre-Coding
Near-Field 3D Distance-Angle Coordinate Precoding Algorithm
Baseband precoding algorithm calculating antenna phase shifts based on exact spherical wavefront curvature to focus energy at 3D spatial points.
Technical Explanation
Conventional far-field precoders (like DFT codebooks) steer beams toward an angular direction (azimuth and elevation). Spherical wavefront precoding incorporates the curvature of the wavefront into the channel matrix, allowing the base station to focus electromagnetic energy at an exact 3D coordinate (x, y, z). Users located along the identical angular line-of-sight but at different distances can receive completely independent data streams with zero mutual interference.
Key Functions
- Calculates phase and amplitude weights based on spherical wave propagation
- Focuses radio energy on an exact 3D spatial coordinate (distance and angle)
- Enables distance-domain multiple access (DDMA) on shared angular directions
- Drastically reduces spatial interference outside the targeted focal sphere
Specifications
3GPP Rel-19 Near-Field Channel Models, IEEE JSAC Near-Field Communications
Interfaces
Digital Baseband Precoding MatrixAntenna Feed Calibration
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