Massive MIMO Channel Information Processing for Lower Feedback Overhead
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Solution Overview
Problem
In massive MIMO systems, the large number of antennas results in significant pilot and feedback overheads for channel estimation and feedback due to the need for channel information feedback on multiple frequency sub-bands, exacerbated by frequency selectivity in OFDM systems.
Innovation Solution
A method and apparatus that utilize downlink and uplink channel estimation to reduce feedback overheads by transmitting and receiving channel information without uplink/downlink reciprocity and deviations between parameters with reciprocity, allowing the network-side device to determine downlink channel information based on these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If channel information feedback is performed for all antennas across multiple frequency sub-bands in massive MIMO systems, then channel estimation accuracy is improved, but feedback overhead increases significantly
Solution Approach 1:
The patent extracts and transmits only the essential channel information parameters (first parameter without reciprocity and deviation information) rather than all channel data. The network-side device performs uplink channel estimation to obtain second parameter with reciprocity, then combines this with terminal's downlink channel estimation (first parameter) and deviation information to reconstruct accurate downlink channel information, significantly reducing feedback overhead while maintaining estimation accuracy
Solution Approach 2:
The patent introduces an intermediary approach where the network-side device acts as a mediator by performing uplink channel estimation and using the reciprocity relationship to infer downlink channel characteristics. This intermediary process allows the system to avoid direct feedback of all downlink channel information across all antennas and frequency sub-bands, reducing feedback overhead while maintaining accuracy
2Measurement precision
If pilot signals are transmitted for channel estimation in massive MIMO systems, then channel information can be obtained, but pilot overhead increases due to large number of antennas
Solution Approach 1:
The patent extracts only the necessary channel information parameters from the full channel state. Instead of requiring pilots for all antennas, the system extracts key parameters (first parameter without reciprocity and deviation from second parameter) that suffice for accurate downlink channel estimation, significantly reducing pilot overhead
Solution Approach 2:
The patent utilizes feedback mechanisms where the terminal feeds back reduced channel information (first parameter and deviation information) and the network-side device uses uplink channel estimation feedback to reconstruct downlink channel information, enabling accurate estimation without requiring exhaustive pilots for all antennas
Data Source
AI summary
A channel information processing method and apparatus. The method includes: receiving first information and second information from a terminal, where the first information includes a first parameter without uplink/downlink channel reciprocity, the first parameter is determined based on downlink channel estimation, the second information is used to indicate a deviation between a second parameter and a third parameter that have uplink/downlink channel reciprocity, the second parameter is determined based on uplink channel estimation, and the third parameter is determined based on downlink channel estimation; and determining channel information of a downlink channel based on the first information, the second information, and the second parameter.