Meaning
Measure of the ability of an antenna system to suppress signals coming from a specific unwanted direction. Spatial null depth indicates the effectiveness of beamforming algorithms in creating quiet zones to avoid causing or receiving interference. It is the ratio between the signal strength in the main beam and the signal strength in the suppressed direction.
A high value means the system can effectively ignore a strong interferer while still communicating with its target.
Noise Suppression
Noise suppression occurs when the antenna array applies specific phase and amplitude weights to cancel out a signal from a particular angle. Deep spatial null depth allows an access point to serve one user while simultaneously placing a null toward another user on the same channel. This capability is the foundation of multi-user MIMO technology.
Antenna Calibration
Physical precision affects the depth of the nulls that the system can generate. Any mismatch in the cables or individual antenna elements limits the maximum spatial null depth because the signals will not perfectly cancel out. Regular calibration procedures are used to compensate for these hardware variances and maintain high levels of isolation.
Temperature changes and physical aging of the components can also drift these values, requiring the system to perform periodic updates to its internal compensation tables.
Network Density
Frequency reuse becomes more efficient when devices can effectively ignore their neighbors. Systems with superior spatial null depth can be packed closer together without degrading the performance of the network. This allows for more total data to be moved through a specific geographic area using the same amount of spectrum.
