Block Diagonal Precoding for Cross-Polarized MIMO Channels

The patent applies local quality by designing codebook elements that are specifically tailored to match the block diagonal structure of cross-polarized antenna channels. Instead of using a universal codebook design for all channel types, the invention creates specialized codebook elements with specific structures (e.g., diagonal matrices, block diagonal matrices) that locally adapt to the characteristics of cross-polarized channels, thereby improving transmission performance without sacrificing codebook design simplicity

The patent employs parameter changes by modifying the codebook elements to have specific structural parameters that match the block diagonal channel structure. The codebook includes elements with varying degrees of diagonality and block structures, allowing the system to select codebook elements whose parameters best match the current channel conditions, thus resolving the contradiction between design simplicity and performance

The patent applies segmentation by dividing the codebook into multiple subsets or groups, each containing codebook elements with specific structures suitable for different channel conditions. This segmentation allows the receiver to search within a smaller subset rather than the entire codebook, reducing signaling overhead while maintaining the ability to select optimal codebook elements for matched channel conditions

The patent implements partial action by including only the most essential and frequently needed codebook elements in the codebook structure. Rather than providing all possible precoding matrices, the codebook includes a carefully selected subset that covers the most common channel scenarios, particularly for cross-polarized antennas, thereby reducing codebook size while maintaining sufficient performance