Polarization Diversity for Cross Polarization Interference Cancellation

The patent transitions from spatial diversity (using multiple antennas in different locations) to polarization diversity (using multiple polarization states of electromagnetic waves). By exploiting the polarization dimension of EM waves rather than spatial separation, the system achieves diversity gain without adding physical antennas, thus resolving the contradiction between reliability improvement and device complexity increase.

The patent changes the parameter being diversified from frequency to polarization state. Instead of allocating multiple frequency bands to achieve diversity, the system uses multiple polarization states (horizontal, vertical, circular) within the same frequency band, thereby maintaining communication availability while reducing frequency spectrum requirements and associated costs.

The patent makes existing antennas multi-functional by enabling them to transmit and receive multiple polarization states simultaneously. A single antenna can handle both horizontal and vertical polarizations, effectively performing the function of multiple antennas without requiring additional physical space on the tower, thus achieving diversity gain while minimizing physical area requirements.

The patent implements a feedback mechanism where the receiver detects the polarization state and signal quality, then sends control signals back to the transmitter to adjust the polarization diversity combining strategy. This closed-loop system optimizes signal reception by adaptively combining polarization components based on current channel conditions, maintaining signal level margin through intelligent signal processing rather than brute-force power increases, thus reducing power consumption and system cost.