FDR Self-Interference Cancellation via Subband Channel Estimation
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Solution Overview
Problem
Full duplex radio (FDR) systems face significant performance deterioration due to intra-apparatus self-interference, which existing technologies have not adequately addressed, necessitating effective self-interference cancellation methods.
Innovation Solution
A method involving measuring residual self-interference signals in multiple subbands, determining the order of non-linear self-interference components for channel estimation, and performing channel estimation on a subband basis to stabilize digital self-interference cancellation, considering frequency selectivity and signal strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex radio is used to double system capacity, then transmission and reception can occur simultaneously, but intra-apparatus self-interference significantly deteriorates system performance
Solution Approach 1:
The patent divides the frequency spectrum into multiple subbands and performs separate channel estimation and self-interference cancellation for each subband. This segmentation allows the system to handle frequency-selective fading differently across subbands, improving cancellation accuracy while maintaining high system capacity in FDR mode
Solution Approach 2:
The patent dynamically adjusts the order of non-linear self-interference signal components based on measured residual self-interference strength in each subband. By changing the parameter of signal component order adaptively, the system achieves accurate cancellation across varying interference conditions while maintaining high productivity
2Measurement precision
If non-linear self-interference signal components are considered for channel estimation, then cancellation accuracy improves, but computational complexity increases
Solution Approach 1:
The patent dynamically determines the order of non-linear self-interference signal components based on measured residual self-interference strength in each subband. This dynamic adjustment allows the system to include higher-order components only when necessary, achieving high measurement precision while avoiding unnecessary computational complexity
Solution Approach 2:
The patent applies different orders of non-linear signal components to different subbands based on their specific interference characteristics. This local quality approach ensures high channel estimation accuracy in each subband while minimizing overall computational complexity by not uniformly applying high-order processing across all subbands
3Object-affected harmful factors
If antenna and analog self-interference cancellations are performed, then residual self-interference is reduced, but frequency selectivity of residual signals requires complex digital processing
Solution Approach 1:
The patent segments the frequency spectrum into multiple subbands to handle frequency-selective residual self-interference signals. By processing each subband separately with appropriate channel estimation, the system reduces residual interference effectively while managing digital processing complexity through structured subdivision
Solution Approach 2:
The patent changes processing parameters (order of non-linear components) adaptively based on residual self-interference strength measurements in each subband. This parameter adjustment allows efficient digital processing that matches the actual interference level, reducing complexity when interference is low while maintaining effectiveness when interference is high
Data Source
AI summary
A method for performing self-interference cancellation by a communication device which uses an FDR mode can comprise the steps of: measuring the strength of a residual self-interference signal, after antenna and analog self-interference cancellation, for each subband with respect to a predetermined number of subbands configured in a communication device; determining the order of a nonlinear self-interference signal component, to be considered for channel estimation of a nonlinear self-interference signal, for each subband on the basis of the strength of the residual self-interference signal that has been measured for each subband; and performing channel estimation of the nonlinear self-interference signal on the basis of the order that has been determined for each subband.