Massive MIMO CSI Feedback via Antenna Group Segmentation
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Solution Overview
Problem
Massive MIMO systems face challenges in efficiently transceiving data, eliminating intra-cell interference (ICI) and noise, and optimizing beamforming due to high overhead in channel state information (CSI) feedback and resource element usage, especially with a large number of antennas.
Innovation Solution
A method for transmitting CSI in a massive MIMO environment involving the reception of reporting period information, measurement of CSI using reference signals, and reporting CSI to a base station, with independent or dependent reporting periods for different antenna sets, allowing for efficient CSI feedback and reduced overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI feedback is performed for all antennas in massive MIMO, then channel state information accuracy is improved, but feedback overhead increases significantly
Solution Approach 1:
The patent divides the massive antenna array into multiple antenna groups, where only selected representative antennas within each group transmit reference signals. This segmentation allows CSI to be measured for groups rather than individual antennas, significantly reducing feedback overhead while maintaining adequate channel state information accuracy for beamforming operations.
Solution Approach 2:
The patent uses reference signals transmitted from selected antennas to represent and infer channel characteristics of other antennas in the same group. By measuring CSI from representative antennas and applying it to group-level beamforming, the system obtains sufficient channel information without requiring feedback from every antenna, thus reducing overhead while preserving measurement utility.
2Measurement precision
If reference signals are transmitted from all antennas, then channel measurement accuracy is improved, but resource element usage increases
Solution Approach 1:
The patent segments the antenna array into multiple groups and configures reference signals to be transmitted only from selected antennas within each group. This reduces the total number of reference signal transmissions and associated resource element consumption while maintaining adequate measurement capability through group-level CSI feedback.
3Power
If beamforming is performed using all antenna elements, then beam gain is maximized, but system complexity increases
Solution Approach 1:
The patent implements beamforming at the antenna group level rather than requiring coordinated control of all individual antenna elements. By forming beams using selected representative antennas from each group, the system achieves substantial beam gain while significantly reducing the computational complexity and control overhead associated with managing massive MIMO arrays.
Data Source
AI summary
The present invention relates to a wireless access system that supports massive MIMO, and provides a method for transceiving channel state information (CSI) for operating the massive MIMO and an apparatus for supporting said method. The method for transmitting CSI by a terminal in a wireless access system that supports massive multi-input multi-output (MIMO), according to one embodiment of the present invention, may comprise the steps of: receiving a signal including report period information; receiving downlink data including a reference signal; measuring first CSI using the reference signal; acquiring second CSI using the first CSI; and reporting the first CSI or the second CSI to a base station based on the report period information. According to the present invention, the first CSI may be information on a first antenna set including antennas for transmitting the reference signal, and the second CSI may be information on a second antenna set including antennas not transmitting the reference signal.