Full-Duplex Self-Interference Cancellation with Two-Level Reconstruction
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Solution Overview
Problem
In wireless full-duplex communications systems, existing self-interference cancellation methods face challenges in achieving effective cancellation while minimizing hardware complexity and cost, particularly due to the large power difference between sending and receiving signals.
Innovation Solution
The proposed solution involves a full-duplex self-interference cancellation method and apparatus that utilizes two-level self-interference reconstruction modules. The method includes time reversal-filtering the sending signal and feeding it into a first self-interference reconstruction module, while directly feeding the sending signal into a second self-interference reconstruction module. This approach reduces hardware complexity and cost by compressing the self-interference channel into a single or few propagation paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the quantity of taps in the radio frequency self-interference cancellation module is increased to cover more reflection transmission paths, then the self-interference cancellation capability is improved, but the area of the module and implementation complexity are increased
Solution Approach 1:
The patent divides the self-interference cancellation process into two separate modules: a radio frequency self-interference cancellation module and a digital self-interference cancellation module. Each module handles different aspects of interference cancellation, allowing the system to achieve comprehensive cancellation without requiring an excessive number of taps in a single module. The radio frequency module uses fewer taps for initial cancellation, while the digital module handles residual interference.
Solution Approach 2:
The patent introduces an intermediate digital signal processing stage between the radio frequency transmission and reception paths. This digital intermediary processes the signals to reconstruct and cancel self-interference components that were not fully eliminated by the radio frequency module, thereby reducing the burden on individual modules and overall system complexity.
2Reliability
If the quantity of taps in the radio frequency self-interference cancellation module is increased to cover more reflection transmission paths, then the self-interference cancellation capability is improved, but the area of the module is increased
Solution Approach 1:
The patent segments the self-interference cancellation function across two distinct modules operating at different stages (radio frequency and digital domains). This segmentation allows each module to use a smaller number of taps, reducing the total hardware area required while maintaining comprehensive interference cancellation coverage across multiple reflection paths.
Solution Approach 2:
The patent creates a digital copy of the transmitted signal to reconstruct the self-interference component. By generating this copy in the digital domain and subtracting it from the received signal, the system achieves interference cancellation without requiring a large number of physical taps in the radio frequency domain, thereby reducing module area.
3Reliability
If guard band or guard interval is used to separate sending signal and received radio frequency signal, then self-interference is avoided, but spectral efficiency and time utilization are reduced
Solution Approach 1:
The patent extracts and separately processes the self-interference component from the received signal through digital signal processing. By identifying and removing the self-interference portion mathematically rather than using guard bands or intervals, the system maintains continuous transmission and reception without sacrificing spectral efficiency or time utilization.
Solution Approach 2:
The patent changes the approach from temporal or spectral separation (guard bands/intervals) to signal processing parameter manipulation. By adjusting digital signal processing parameters to reconstruct and cancel self-interference, the system achieves interference avoidance while maintaining full spectral and temporal utilization.
Data Source
AI summary
Embodiments of this application disclose a full-duplex self-interference cancellation method and apparatus. The full-duplex self-interference cancellation method may be applied to the field of radio frequency self-interference cancellation in a full-duplex scenario. The full-duplex self-interference cancellation method is implemented by a full-duplex self-interference cancellation apparatus with self-interference reconstruction modules of two levels, and the full-duplex self-interference cancellation apparatus is implemented by a terminal. This greatly reduces hardware implementation complexity and costs of the second self-interference reconstruction module, and improves a full-duplex self-interference cancellation capability.