LTE Downlink Parameter Reporting for Multi-Point Reception Reliability
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Solution Overview
Problem
When downlink signals are transmitted from multiple transmission points to a user terminal in LTE systems, the reliability of reception can decrease due to varying signal characteristics, and there is a need for adequate reporting of associations and mapping patterns between these signals to ensure proper receiving processes.
Innovation Solution
A method is proposed to report parameter information, including PDSCH resource mapping and quasi-co-location configurations, to user terminals using higher layer signaling, which allows them to perform rate matching and channel estimation accurately, even when signals come from multiple transmission points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If downlink signals are transmitted from multiple transmission points to improve data rates and spectral efficiency, then system performance is improved, but reception reliability decreases due to varying signal characteristics
Solution Approach 1:
The patent segments the downlink signal transmission by associating different reference signals (CRS, CSI-RS) with different transmission points. Each transmission point transmits signals with distinct characteristics, and the user terminal performs separate channel estimation for each transmission point based on its specific reference signals. This segmentation allows the system to maintain multiple transmission paths while managing signal characteristics individually, thereby preserving reception reliability despite using multiple transmission points for improved data rates.
2Area of stationary object
If downlink signals from multiple transmission points are transmitted separately to improve coverage, then system capacity is improved, but receiving process accuracy deteriorates due to different signal characteristics
Solution Approach 1:
The patent applies local quality by configuring transmission-specific parameters (such as resource element mappings, reference signal patterns) according to the characteristics of each transmission point. The user terminal adapts its receiving processes locally for each transmission point based on the specific signal characteristics received, rather than using a uniform receiving process for all transmission points. This enables accurate channel estimation and signal reception despite variations in coverage areas and signal characteristics across multiple transmission points.
3Measurement precision
If rate matching is performed considering mapping patterns of control signals and reference signals from each transmission point, then reception accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent employs preliminary action by pre-configuring the user terminal with transmission-specific parameter information through higher-layer signaling before actual data reception. The mapping patterns of control signals and reference signals from each transmission point are established in advance, allowing the user terminal to perform rate matching based on these pre-known patterns. This preliminary configuration reduces the real-time processing complexity while maintaining high reception accuracy, as the terminal does not need to dynamically determine complex mapping relationships during active reception.
Data Source
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Figure 2A~2B
Figure 3A~3D
AI summary
The present invention is designed to reduce the decrease of the reliability of reception by reporting information that is required in receiving processes to user terminals, even when downlink signals are transmitted from a plurality of transmission points to a user terminal. A radio communication system to have a plurality of radio base stations and a user terminal that is capable of coordinated multiple point transmission with the plurality of radio base stations is provided, and, in this radio communication system, a radio base station has a generating section that generates parameter information related to downlink signals, a control information generating section that generates downlink control information that includes an indicator to represent specific parameter information, a control section that controls whether or not to configure a bit field for the indicator of the parameter information in the downlink control information, and a transmission section that transmits information as to whether or not the bit field for the indicator of the parameter information is configured, to the user terminal, by higher layer signaling.