Precoding Weight Subset Selection for Wireless Coverage
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Solution Overview
Problem
In wireless communication systems, especially MIMO and MISO systems with reconfigurable antennas, the large number of precoding weights required leads to time-consuming calculations, high energy consumption, and a higher probability of choosing unphysical precoding vectors, which reduces system performance and increases the size of the codebook needed for communication.
Innovation Solution
A method to determine and use a subset of precoding weights stored in a codebook, specifically selecting a part of the coverage area and informing user equipment of the corresponding precoding weights, thereby reducing the number of bits sent and calculations needed, and minimizing the chance of choosing unphysical weights by limiting the codebook to only those generating beams within the selected coverage area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large codebook with many precoding weights is used to support multiple antennas at the base station, then the coverage area and capacity are improved, but the calculation time and energy consumption at the UE increase significantly
Solution Approach 1:
The patent segments the codebook into multiple subsets based on different coverage areas or beam directions. The UE is provided with only the relevant subset corresponding to its current location or service area, rather than the complete large codebook. This segmentation reduces the calculation burden while maintaining full coverage capability across different regions.
Solution Approach 2:
Different subsets of precoding weights are optimized for different local conditions (coverage areas, beam directions, or UE locations). Each subset contains precoding weights tailored to specific spatial regions, allowing the UE to use a smaller, locally-optimized codebook instead of a globally-comprehensive one, thus reducing calculation time while maintaining performance.
2Productivity
If a large codebook with many precoding weights is used to support multiple antennas, then the system capacity is improved, but the number of bits required for PMI feedback increases
Solution Approach 1:
The codebook is segmented into multiple subsets, each associated with a specific coverage area or beam direction. The UE only needs to select from the relevant subset, reducing the number of bits required for PMI feedback. The base station maintains the full codebook for high system capacity, while the UE operates with a reduced subset.
Solution Approach 2:
The patent introduces an additional dimension to the codebook structure by organizing precoding weights not just by size but by spatial coverage area or beam direction. This dimensional organization allows the system to maintain large overall capacity while enabling the UE to select from smaller, spatially-grouped subsets, reducing feedback overhead.
3Adaptability or versatility
If a large codebook with many precoding weights is used, then the precoding flexibility is improved, but the probability of selecting un-physical precoding vectors increases
Solution Approach 1:
The codebook is segmented into subsets where each subset contains only precoding weights appropriate for specific coverage areas or beam directions. This segmentation ensures that the UE selects from physically-valid options for its current condition, reducing the probability of selecting un-physical vectors while maintaining overall precoding flexibility across different scenarios.
Solution Approach 2:
Each subset is locally optimized to contain only physically-valid precoding weights for specific spatial conditions. By providing the UE with a locally-appropriate subset rather than the complete codebook, the system ensures that all selectable options are physically valid for the current situation, improving selection accuracy while maintaining flexibility through multiple specialized subsets.
4Area of stationary object
If reconfigurable antennas are used to change beam direction and width, then the coverage area is improved, but the mismatch between precoding beams and antenna radiation patterns increases when using fixed precoding weights
Solution Approach 1:
The patent makes the codebook dynamic by providing different subsets to the UE based on the current antenna configuration (beam direction and width). When the reconfigurable antennas change their radiation pattern, the base station provides a corresponding subset of precoding weights that matches the new configuration, ensuring continuous alignment between precoding beams and antenna patterns.
Solution Approach 2:
Different subsets of precoding weights are optimized for different antenna configurations and coverage areas. Each subset contains precoding weights that are locally-matched to specific beam directions and widths, ensuring that when reconfigurable antennas change their radiation pattern, the UE can select from a subset that maintains proper alignment between precoding beams and antenna patterns.
Data Source
AI summary
The present invention relates to a method for determining precoding weights between a base station and one user equipment in a communication network. The base station is provided with an antenna structure having multiple antennas, and the antenna structure provides coverage in a coverage area. The precoding weights are stored in a codebook available to the base station and the user equipment. The method comprises: selecting to use a part of the coverage area; determining, at the base station, a subset of precoding weights stored in the codebook generating at least one precoding beam within the selected part of the coverage area; and informing the one user equipment of the determined subset of precoding weights generating the at least one precoding beam within the selected part of the coverage area.