Radio Base Station Beamforming for Reduced CSI Feedback
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Solution Overview
Problem
In LTE and LTE-A systems, the calculation processing load and CSI feedback data increase exponentially with the number of MIMO multiplexing, leading to higher power consumption and data volume in user terminals, particularly affecting terminals on cell edges and near cell centers.
Innovation Solution
A radio communication system with a radio base station featuring an array antenna divided into groups, generating separate beams for cell edges and cell centers using precoding weights, and a user terminal that receives and measures these beams to feed back communication quality information, reducing the calculation load and CSI feedback data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of MIMO multiplexing is increased to improve system capacity, then the data rate and spectral efficiency are improved, but the calculation processing load and CSI feedback data increase exponentially
Solution Approach 1:
The patent divides the array antenna into multiple groups (e.g., first group and second group) and forms separate beams (first beam and second beam) for different spatial directions (cell edge and cell center). This segmentation allows the system to handle multiple users simultaneously with reduced calculation load per user, as each user terminal only needs to process reference signals for its designated beam rather than all possible MIMO multiplexing combinations.
2Productivity
If the number of MIMO multiplexing is increased to improve system capacity, then the data rate and spectral efficiency are improved, but the amount of CSI feedback data increases exponentially
Solution Approach 1:
The patent segments the reference signal resources by allocating different reference signals to different beam groups. User terminals only measure and feedback CSI for their assigned beam's reference signals, significantly reducing the total CSI feedback data volume while maintaining system capacity through spatial multiplexing of multiple beams.
3Productivity
If the number of MIMO multiplexing is increased to improve system capacity, then the data rate and spectral efficiency are improved, but the power consumption of user terminals increases
Solution Approach 1:
The patent reduces power consumption by segmenting the beamforming space and assigning specific beams to specific user terminals. This allows terminals to focus their processing resources on measuring and feedback for only their assigned beam's reference signals rather than processing all reference signals across all MIMO multiplexing configurations, thereby reducing computational power consumption.
4Productivity
If separate beams are formed for cell edge and cell center using precoding weights, then user terminals on cell edges and near centers can be multiplexed to increase capacity, but the antenna system complexity increases
Solution Approach 1:
The patent segments the array antenna into multiple groups and forms separate beams for different spatial directions. This segmentation enables spatial multiplexing of users in different directions (cell edge and cell center) while managing complexity through structured precoding weight generation for each beam group, allowing the system to handle multiple users simultaneously with organized resource allocation.
Solution Approach 2:
The patent applies different precoding weights to different antenna groups to create beams optimized for specific spatial directions. Each beam group has locally optimized characteristics (different precoding weights) suited for its target direction, enabling effective service to users at different locations (cell edge vs. cell center) with direction-specific beamforming parameters.
Data Source
AI summary
The present invention is designed to reduce the increase in the amount of the calculation process in a mobile station and the amount of CSI feedback data, and also prevent the amount of overall system capacity from decreasing. This radio communication system (1) has a radio base station (200) which can form a plurality of beams that are vertically sectorized. The radio base station (200), using an array antenna (10), forms at least the first beam that is directed to the cell edge side and a second beam that is directed to the cell center side, in parallel. A mobile station (100) measures channel quality by extracting reference signals from each of the first beam and the second beam, generates a communication quality feedback signal including channel quality measured from at least one of the beams, and feeds this back to the radio base station (200) via the uplink.