UE Feedback for Massive Antenna Array Beamforming
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently performing feedback for massive antenna array based beamforming, particularly in accurately reporting channel variations, which affects the effectiveness of beamforming in wireless communication systems like LTE.
Innovation Solution
A method is introduced where user equipment (UE) receives pilot signals at different times, measures channel quality, and transmits feedback information to the base station about the variation between these channel qualities, including preferred precoder index variations, to enable efficient beamforming. This method involves selecting precoding matrix indices from a codebook and reporting differences, ensuring accurate channel variation feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional feedback methods are used for massive antenna array beamforming, then the system structure remains simple, but the feedback accuracy and beamforming effectiveness deteriorate
Solution Approach 1:
The feedback mechanism is segmented into two parts: the base station transmits pilot signals with different precoding matrices, and the UE measures and reports only the variation in channel quality indicators (CQI) corresponding to different precoder indices. This segmentation allows the UE to focus on reporting channel variations rather than transmitting complete channel state information, thereby improving feedback accuracy while controlling complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the UE measures channel quality for different precoding matrices and reports the variation in CQI values back to the base station. This feedback loop enables the base station to adapt the precoding matrices for beamforming, significantly improving beamforming effectiveness and channel variation feedback accuracy.
2Productivity
If detailed channel state information is transmitted by UE, then beamforming performance improves, but feedback overhead and transmission time increase
Solution Approach 1:
The patent extracts only the essential information needed for beamforming optimization from the complete channel state information. Specifically, the UE measures and reports only the variation in CQI values corresponding to different precoder indices, rather than transmitting the entire channel matrix. This extraction approach maintains beamforming effectiveness while significantly reducing feedback overhead and transmission time.
Solution Approach 2:
Instead of transmitting complete channel state information (excessive action), the patent employs partial action by reporting only the variation in CQI for different precoding matrices. This partial feedback provides sufficient information for the base station to optimize beamforming without the time overhead of transmitting full channel state data.
3Reliability
If the UE reports complete channel quality information, then the base station can optimize beamforming accurately, but the feedback complexity and processing burden increase
Solution Approach 1:
The patent extracts only the critical feedback elements (CQI variations for different precoder indices) from the complete channel state information. This extraction maintains the reliability of beamforming optimization by providing the base station with the necessary variation information, while significantly reducing the processing complexity at both UE and base station sides.
Solution Approach 2:
The patent changes the feedback parameter from complete channel state information to CQI variation values. This parameter transformation simplifies the feedback data structure and processing requirements while maintaining the reliability of beamforming optimization, as the CQI variations directly indicate the performance difference between different precoding matrices.
Data Source
AI summary
A method for transmitting feedback information to a base station at a user equipment (UE) in a wireless communication system is disclosed. The method includes receiving a pilot signal from the base station at a first time and a second time, measuring first channel quality at the first time and second channel quality at the second time based on the pilot signal and transmitting the feedback information including information about a variation value between the first channel quality and the second channel quality to the base station.