Precoding Matrix Resolution Control With Beam Interpolation
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Solution Overview
Problem
The existing LTE system fails to adjust the resolution of the codeword in the codebook generated from column selection of DFT beam vectors flexibly, leading to performance degradation.
Innovation Solution
The method involves determining and transmitting first and second pre-coding indication information by a UE, which includes direction weighting vectors and phase adjusting factors for interpolation and phase adjustment, allowing for flexible adjustment of the pre-coding matrix, enabling precise orientation of beam vectors and maintaining constant transmit power across antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If column selection from subset of DFT beam vectors is used to generate codebook, then codebook structure is well-defined and simple, but resolution of codeword cannot be adjusted flexibly
Solution Approach 1:
The patent introduces a dynamic resolution adjustment mechanism by adding a resolution indication parameter that allows the UE to select different resolution levels (first resolution or second resolution) for PMI2 feedback. This enables the system to adaptively change the precision of beam vector selection based on channel conditions and performance requirements, resolving the contradiction between fixed structure and flexible resolution adjustment.
Solution Approach 2:
The patent changes the resolution parameter of the codebook by introducing different resolution levels for PMI2 feedback. When first resolution is used, finer granularity beam vectors are selected; when second resolution is used, coarser granularity beam vectors are selected. This parameter change approach allows flexible resolution adjustment while maintaining the same codebook structure, resolving the contradiction between structure simplicity and resolution flexibility.
2Reliability
If fixed DFT beam vectors are used for pre-coding matrix generation, then codebook structure is simple and well-defined, but system performance degrades due to inability to adjust resolution
Solution Approach 1:
The patent makes the codebook resolution dynamic by allowing the UE to indicate different resolution levels through the resolution indication parameter. The eNB can adaptively adjust the resolution requirement based on channel conditions, signal quality, and performance needs, thereby improving system reliability while maintaining adaptability through the dynamic resolution selection mechanism.
Solution Approach 2:
The patent improves system performance by enabling parameter changes in the resolution level. When channel conditions are good, higher resolution can be used for more precise beamforming; when conditions are poor or traffic load is high, lower resolution can be used to reduce feedback overhead and processing complexity, thus improving overall system reliability and adaptability.
3Measurement precision
If high-resolution beam vector selection is used, then orientation precision is improved, but feedback overhead and processing complexity increase
Solution Approach 1:
The patent dynamically adjusts the feedback resolution based on actual system needs. The resolution indication parameter allows the UE to select between first resolution (higher precision, more feedback bits) and second resolution (lower precision, fewer feedback bits). This dynamic adjustment resolves the contradiction by allowing high precision when needed while reducing feedback overhead when high precision is not necessary.
Solution Approach 2:
The patent changes the resolution parameter of beam vector selection to balance precision and feedback overhead. By introducing different resolution levels, the system can achieve high measurement precision when required (using first resolution with more PMI2 bits) while reducing feedback information quantity when high precision is not critical (using second resolution with fewer PMI2 bits), thus resolving the contradiction between precision and feedback overhead.
Data Source
AI summary
Methods and apparatuses for transmitting coding indication information and determining a precoding matrix, for use in resolving the problem that the resolution of code words in a codebook generated by using a combination of a beam vector subgroup and column selection cannot be flexibly adjusted. The method comprises: determining first precoding indication information and second precoding indication information, the first precoding indication information corresponding to a first-stage precoding matrix, the second precoding indication information corresponding to a direction weighting vector and a phase adjustment factor, the direction weighting vector being used for performing interpolation processing on parts representing angles corresponding to beam vectors in the all beam vectors in each polarization direction in the first-stage precoding matrix, the phase adjusting factor being used for performing phase adjustment on different polarization directions of the first-stage precoding matrix, and the first-stage precoding matrix, the direction weighting vector, and the phase adjustment factor being used for generating a precoding matrix. The resolution of a precoding matrix is flexibly adjusted by using a direction weighting vector.