Full Duplex Radio Self-Interference Removal via Branched RF Chains
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Solution Overview
Problem
Full-duplex communication systems face significant performance deterioration due to intra-device self-interference, which needs to be efficiently cancelled to operate effectively.
Innovation Solution
A method for self-interference cancellation in Full Duplex Radio (FDR) systems involves branching residual self-interference signals into multiple receive RF chains, combining them based on signal strength and predefined thresholds, and determining the need for digital self-interference cancellation using a processor. This includes calculating combining coefficients and performing digital cancellation based on signal correlations and thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex communication is implemented to double system capacity, then transmission and reception can occur simultaneously, but intra-device self-interference significantly deteriorates system performance
Solution Approach 1:
The patent segments the self-interference cancellation process into multiple stages: antenna-level cancellation, RF chain-level cancellation, and digital baseband cancellation. By dividing the interference cancellation task across different layers of the communication stack, the system can effectively reduce self-interference while maintaining full-duplex operation
Solution Approach 2:
The patent introduces an intermediary signal processing chain that creates a model of the self-interference signal and subtracts it from the received signal. This intermediary cancellation mechanism acts as a mediator between the transmitted and received signals, preventing the harmful interference from degrading system performance
2Reliability
If multiple receive RF chains are used to process signals, then signal processing capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the self-interference cancellation function into the existing receive RF chain structure. By combining the cancellation operations across multiple RF chains and coordinating their processing, the system achieves improved signal processing capability without proportionally increasing overall device complexity
Solution Approach 2:
The patent designs the receive RF chains to perform multiple functions: standard signal reception and self-interference cancellation. By making the RF chains multi-functional, the system avoids adding separate dedicated cancellation hardware, thereby managing device complexity while maintaining reliability
3Measurement precision
If digital self-interference cancellation is performed on all branched signals, then cancellation performance is improved, but processing overhead and complexity increase
Solution Approach 1:
The patent applies digital self-interference cancellation selectively rather than uniformly to all branched signals. By performing cancellation only where necessary based on signal characteristics and interference levels, the system achieves adequate cancellation performance while avoiding unnecessary processing overhead
Solution Approach 2:
The patent implements different cancellation strategies for different RF chains based on their specific signal qualities and interference conditions. By tailoring the cancellation approach to local requirements rather than applying a uniform method everywhere, the system optimizes the balance between cancellation performance and processing complexity
Data Source
AI summary
A method for performing self-interference removal by a communication device using a full-duplex radio (FDR) mode, according to an embodiment of the present invention, comprises a step for branching a residual self-interference signal, after removal of an antenna self-interference signal, into a plurality of reception RF chains. And the present invention enables determining of whether or not digital self-interference removal is to be performed after combining the plurality of self-interference signals, which have been branched, on the basis of a predefined threshold and strength of each of the plurality of self-interference signals that have been branched.