Channel State Information Feedback via Dimension Extraction
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Solution Overview
Problem
In 3GPP LTE and LTE-A systems with a large number of antennas, obtaining complete and accurate channel state information (CSI) becomes challenging due to excessive pilot overheads and computational complexity, which reduces system throughput and strains baseband processing capabilities.
Innovation Solution
A method and apparatus that reduce pilot overheads and computational complexity by feeding back channel dimension information, including an effective dimension and subspace index of a statistical channel subspace, which is less than the number of reference signal ports, allowing for dimension-reduced precoding and feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete real-time CSI is obtained using traditional downlink or uplink pilot methods, then channel state information accuracy is improved, but pilot overheads and computational complexity increase excessively
Solution Approach 1:
The patent extracts only the essential channel state information (effective dimension and subspace index) from the complete channel matrix, discarding redundant details. This allows the base station to obtain sufficient CSI for precoding without measuring or processing the entire channel matrix, thereby reducing pilot overheads and computational complexity while maintaining measurement precision.
Solution Approach 2:
Instead of obtaining complete CSI for all antennas, the patent uses partial CSI (effective dimension and subspace index) that is sufficient for precoding operations. This partial action approach reduces the quantity of information to be processed while still achieving the necessary channel state knowledge for effective data transmission.
2Quantity of substance
If traditional pilot methods are used to obtain CSI for large quantity of antennas, then channel state information completeness is improved, but time-frequency resources for data transmission are reduced
Solution Approach 1:
The patent extracts only the necessary channel state parameters (effective dimension and subspace index) from the complete channel information. This extraction allows the system to maintain CSI completeness for precoding purposes while significantly reducing the time-frequency resources consumed by pilots, thereby improving system throughput.
Solution Approach 2:
The patent changes the representation of channel state information from the traditional complete channel matrix to a compressed parameter form (effective dimension and subspace index). This parameter transformation reduces the amount of data that needs to be transmitted via pilots, freeing up time-frequency resources for data transmission and improving overall system throughput.
3Adaptability or versatility
If complete CSI is obtained for massive antennas, then spatial degrees of freedom are fully utilized, but baseband processing capability is strained
Solution Approach 1:
The patent extracts only the essential channel state parameters (effective dimension and subspace index) that are sufficient for precoding, rather than processing the complete channel matrix for all antennas. This extraction approach allows the system to utilize spatial degrees of freedom for MIMO operations while significantly reducing baseband processing requirements.
Solution Approach 2:
Instead of performing complete channel state estimation and processing for all antennas, the patent applies partial action by processing only the effective dimension and subspace index. This partial processing approach is sufficient for precoding operations and maintains the ability to exploit spatial degrees of freedom without straining baseband processing capabilities.
Data Source
AI summary
Embodiments of the present disclosure provide a method for obtaining channel state information, including: sending, by a base station, one or multiple pieces of downlink signaling to user equipment, where the one or multiple pieces of downlink signaling instruct the user equipment to feed back channel dimension information, where the channel dimension information includes an effective dimension of a channel subspace of a statistical channel between the base station and the user equipment, and the effective dimension of the channel subspace is less than a quantity of reference signal ports used to measure channel state information; and receiving, by the base station, the channel dimension information fed back by the user equipment.