Frequency Offset Estimation in Distributed Microwave MIMO Systems
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Solution Overview
Problem
Conventional MIMO frequency offset estimation methods are inaccurate for distributed microwave MIMO systems due to inconsistent frequency offsets between outdoor units, leading to inaccurate channel estimation results.
Innovation Solution
A method and apparatus for frequency offset estimation and channel estimation that iteratively corrects frequency offsets and uses pseudo-inverse operations of cyclic shift matrices formed by orthogonal codes to obtain accurate interference signals, improving estimation accuracy through cyclic iteration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MIMO frequency offset estimation method is used, then the estimation process is simple, but the frequency offset estimation result is inaccurate due to inconsistent frequency offsets between distributed ODUs
Solution Approach 1:
The patent segments the frequency offset estimation process into two distinct phases: initial estimation without interference signals, and refined estimation with interference signals. This segmentation allows each phase to be optimized independently, improving overall accuracy without overwhelming complexity.
Solution Approach 2:
The patent performs preliminary frequency offset estimation before interference signal removal, establishing an initial estimate that guides subsequent processing. This preliminary action enables the system to have a starting point for refinement, improving final accuracy while maintaining manageable complexity.
Solution Approach 3:
The patent implements feedback by using the initially estimated frequency offset to guide interference signal removal, then using the cleaned signal to refine the frequency offset estimation. This iterative feedback loop continuously improves accuracy while the structured approach prevents complexity from becoming unmanageable.
2Measurement precision
If conventional channel estimation method is used, then the processing is straightforward, but the channel estimation result includes residual frequency offset information and is inaccurate
Solution Approach 1:
The patent performs preliminary frequency offset correction before channel estimation. By removing frequency offset effects in advance, the subsequent channel estimation operates on corrected data, significantly improving accuracy while the sequential structure keeps processing complexity manageable.
Solution Approach 2:
The patent extracts and removes interference signals containing residual frequency offset information before performing channel estimation. By taking out the harmful frequency offset components, the channel estimation operates on cleaner data, improving accuracy without requiring fundamentally complex processing.
3Measurement precision
If iterative frequency offset correction and channel estimation is performed, then the estimation accuracy is significantly improved, but the computational complexity increases
Solution Approach 1:
The patent implements periodic iteration between frequency offset estimation, interference removal, and channel estimation. This periodic cycling continues until convergence or a maximum number of iterations is reached, achieving high accuracy while the structured periodic nature allows for efficient resource management and prevents excessive computational power consumption.
Data Source
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AI summary
Embodiments of the present invention provide a method, an apparatus, and a system for frequency offset estimation and channel estimation, relate to the field of wireless communication technologies, and can increase the accuracy of frequency offset estimation and channel estimation in a distributed microwave MIMO system. The method for frequency offset estimation and channel estimation includes: when interference signals in received data are not obtained, performing frequency offset estimation on the received data, and obtaining a frequency offset estimation result; after the interference signals in the received data are obtained, performing frequency offset estimation on the received data according to the interference signals, and obtaining a frequency offset estimation result; performing channel estimation on the received data according to the frequency offset estimation result, and obtaining a channel estimation result; obtaining the interference signals according to the frequency offset estimation result and the channel estimation result, where the interference signals are used as parameters of the frequency offset estimation.