Two-Level CSI Feedback for Multi-Antenna Throughput
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Solution Overview
Problem
In LTE/LTE-A systems with a large number of antennas, high uplink and downlink pilot overheads and CSI feedbacks consume significant time-frequency resources, reducing system throughput due to increased pilot overheads and CSI feedbacks.
Innovation Solution
A two-level CSI measurement method where terminal devices receive downlink control signaling to feed back statistical and instantaneous channel parameter information, with the network device precoding level-two RS signals based on statistical channel information to reduce dimensionality and quantify instantaneous channel information, allowing for efficient two-level precoding of downlink data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of antennas are deployed at the data transmit end to increase spatial freedom and support more UEs, then the quantity of to-be-served UEs and data transmission capacity increase, but the downlink pilot overheads increase proportionally, consuming more time-frequency resources
Solution Approach 1:
The patent segments CSI feedback into two distinct parts: wideband CSI (WB-CSI) for long-term channel statistics and subband CSI (SB-CSI) for short-term channel variations. This segmentation allows the system to separately handle different aspects of channel information, reducing the overall feedback overhead while maintaining accuracy for large-scale antenna systems
Solution Approach 2:
The patent extracts and separates the wideband CSI component from the total CSI feedback requirement. By taking out the wideband part (which changes slowly) and handling it separately from the subband part (which changes rapidly), the system reduces redundant feedback and optimizes resource usage in multi-antenna configurations
2Productivity
If the quantity of antennas at the data transmit end increases to provide higher spatial freedom, then multiplexing capability for multiple data streams improves, but the quantity of uplink CSI feedbacks increases proportionally, occupying more time-frequency resources
Solution Approach 1:
The patent divides uplink CSI feedback into wideband and subband components, allowing the system to report essential channel information at wideband level and detailed variations only at subband level. This segmentation significantly reduces the total quantity of uplink CSI feedbacks required for large-scale antenna systems
Solution Approach 2:
The patent applies partial action by reporting only the necessary portion of CSI at full resolution (subband level), while using compressed or statistical representations for the wideband component. This partial detailing approach reduces feedback overhead while maintaining sufficient accuracy for MIMO multiplexing operations
3Measurement precision
If downlink pilot overheads and uplink CSI feedbacks increase with more antennas, then channel state information accuracy improves, but fewer time-frequency resources remain available for data transmission, reducing system throughput
Solution Approach 1:
By segmenting CSI feedback into wideband and subband components, the patent achieves efficient resource allocation where high-precision feedback is provided only where necessary (subband), while wideband uses compressed representations. This maintains measurement precision for data transmission while freeing up time-frequency resources
Solution Approach 2:
The patent changes the representation parameters of CSI feedback by using different granularities (wideband vs. subband) and different compression levels for different parts of the channel information. This parameter variation maintains essential accuracy while reducing overall feedback volume, thereby increasing available resources for data transmission
Data Source
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AI summary
Embodiments of the present invention relate to a multi-antenna data transmission method, network device, terminal device, and system. The method includes: sending, by a network device, downlink control signaling to a terminal device, where the downlink control signaling instructs the terminal device to feed back statistical channel parameter information, the statistical channel parameter information is determined by the terminal device according to statistical channel information, and the statistical channel information is obtained by means of computation after the terminal device measures instantaneous channels many times; receiving, by the network device, the statistical channel parameter information that is determined according to the downlink control signaling and that is sent by the terminal device; and processing, by the network device, downlink data according to the statistical channel parameter information, and sending processed downlink data to the terminal device. The multi-antenna data transmission method, network device, terminal device, and system provided in the embodiments of the present invention can effectively increase a system throughput.