Hybrid Beamforming Subset Selection for MIMO Channel Correlation
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Solution Overview
Problem
Hybrid beamforming in wireless communication systems faces challenges in selecting optimal beam combinations for data transmission, particularly in managing channel correlation between RF chains, which affects performance in MIMO modes such as spatial multiplexing and diversity, leading to suboptimal Signal-to-Noise Ratio (SNR) gains and increased channel path independence.
Innovation Solution
A method for determining transmit beam combinations based on subset information, where analog beams with correlations less than a threshold are selected for spatial multiplexing or diversity, using a combination of channel quality calculations and correlation management to optimize beamforming coefficients and precoding matrices for improved channel quality and SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple analog beams are used for MIMO transmission, then data transmission capacity is improved, but channel correlation increases leading to performance degradation
Solution Approach 1:
The patent segments the analog beams into multiple subsets based on their correlation characteristics. Each subset contains beams with correlations below a threshold value. This segmentation allows the system to select appropriate subsets for different MIMO modes, ensuring channel independence while maintaining transmission capacity.
Solution Approach 2:
The patent changes the parameter of beam correlation by selecting beams from different subsets with controlled correlation values. By adjusting which subsets are used for transmission, the system can optimize the correlation parameter to match the requirements of different MIMO modes, preventing performance degradation.
2Reliability
If beamforming coefficients are adjusted for optimal performance, then SNR gain is improved, but system complexity increases
Solution Approach 1:
The patent performs preliminary classification of analog beams into subsets based on correlation values before actual transmission. This preliminary action organizes the beamforming coefficients in advance, allowing the system to simply select from pre-defined subsets rather than performing complex real-time adjustments, thus reducing system complexity while maintaining SNR gain.
3Device complexity
If RF chains are reduced to lower cost, then device complexity is reduced, but beamforming flexibility is limited
Solution Approach 1:
The patent segments the beamforming functionality across multiple subsets of analog beams, allowing a reduced number of RF chains to access a larger effective beam space. By selecting from multiple subsets with different correlation characteristics, the system achieves beamforming flexibility comparable to systems with more RF chains, thus lowering device complexity while maintaining adaptability.
Data Source
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AI summary
A method for operating a receiving end in a wireless communication system includes receiving subset information on analog beams of a transmitting end, from a transmitting end, and determining a combination of transmit beams to be used for data signal transmission to the receiving end, on the basis of the subset information, wherein the subset information indicates at least one subset into which the analog beams are classified, and each analog beam of the at least one subset has a correlation equal to or less than a threshold, with one another. An apparatus for a receiving end includes a communication unit configured to receive subset information on analog beams of a transmitting end, from the transmitting end, and a controller configured to determine a combination of transmit beams to be used for data signal transmission to the receiving end, on the basis of the subset information.