Precoder for Cross-Polarized Antenna Array
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Solution Overview
Problem
Current feedback schemes for cross-polarized linear antenna arrays in LTE systems do not fully match channel characteristics, leading to inefficient system performance.
Innovation Solution
A precoding method and precoder that generate a feedback codebook with a complex scaling relation between coefficients for each group of coplanar polarized antennas, using candidate amplitudes and phases to match channel characteristics, resulting in a precoding matrix that enhances coding performance and reduces feedback overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feedback schemes with co-phasing precoder form are used, then implementation simplicity is maintained, but channel characteristics matching is insufficient leading to suboptimal system performance
Solution Approach 1:
The patent changes the parameter structure of the precoder from simple co-phasing form to a form incorporating complex scaling factors (amplitude and phase). The precoder is defined as F = [f1, ejδ1f1, ..., eLjδLfL] where δ represents phase differences and amplitude scaling is applied to match channel characteristics, thereby improving system performance while maintaining manageable complexity through structured parameterization
Solution Approach 2:
The feedback codebook is designed to be adaptive to channel conditions by incorporating channel-dependent parameters. The codebook structure allows dynamic adjustment of precoding parameters based on channel state information, enabling the system to adapt to varying channel characteristics and improve reliability under different propagation conditions
2Reliability
If feedback codebook is designed to fully match channel characteristics with complex scaling relation, then coding performance is improved, but feedback overhead increases
Solution Approach 1:
The feedback codebook is segmented into multiple sub-codebooks, each corresponding to different channel conditions or parameter ranges. This segmentation allows the system to select appropriate sub-codebooks based on channel state, providing accurate channel matching when needed while reducing feedback overhead by not always requiring full codebook feedback. The segmentation enables hierarchical feedback strategies where only necessary parameters are reported
Solution Approach 2:
The patent applies partial action by selectively applying complex scaling relations only to the extent necessary for achieving desired performance. Rather than fully matching all channel characteristics in all conditions, the system uses the complex scaling precoder structure to provide sufficient matching for dominant channel components while accepting approximate matching for less significant components, thereby reducing feedback overhead while maintaining adequate coding performance
Data Source
AI summary
The present invention provides a precoding method for a cross-polarized antenna array, the cross-polarized antenna array comprising a first group of coplanar polarized antennas and a second group of coplanar polarized antennas, the method comprising the following steps: generating, for at least one layer of data stream, a feedback codebook comprising a plurality of codewords; receiving a selection of the codeword in the feedback codebook; determining a corresponding codeword from the feedback codebook according to the received selection; generating a precoding matrix based on the determined codeword to precode the at least one layer of data stream; wherein each codeword in the feedback codebook comprises a first coefficient portion corresponding to a first group of coplanar polarized antennas and a second coefficient portion corresponding to the second group of coplanar polarized antennas, and there is a complex scaling relation between the coefficients in the first coefficient portion and the second coefficient portion corresponding to the same layer of data stream. Correspondingly, the present invention further provides a precoder for a cross-polarized antenna array.