Self-Interference Cancellation in Full Duplex Radio Systems
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Solution Overview
Problem
Full duplex radio (FDR) systems face significant performance deterioration due to intra-device self-interference, which existing methods have not effectively addressed, particularly in managing self-interference cancellation.
Innovation Solution
A method and apparatus for performing self-interference cancellation in FDR environments by performing channel estimation of a received self-interference reference signal, calculating power values for non-linear self-interference signal components, and establishing a non-linear digital self-interference cancellation order based on these power values, adapting the order according to predefined thresholds and channel estimation results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full duplex radio (FDR) mode is used to simultaneously perform transmission and reception, then system capacity is doubled compared to half duplex communication, but intra-device self-interference greatly deteriorates FDR system performance
Solution Approach 1:
The self-interference cancellation process is segmented into multiple orders (first order, third order, fifth order, etc.), where each order corresponds to a specific level of non-linearity. The system calculates power values for each order component and selectively cancels only those orders whose power exceeds a threshold, thereby dividing the complex cancellation task into manageable segments.
Solution Approach 2:
The system dynamically changes the cancellation order parameter based on calculated power values. When the power value of a lower order component is higher than that of a higher order by a predefined value, the system establishes the non-linear self-interference cancellation order to be considered as the two orders. This adaptive parameter adjustment optimizes cancellation effectiveness while reducing complexity.
2Measurement precision
If non-linear self-interference cancellation is performed by calculating power values for multiple order components, then self-interference cancellation accuracy is improved, but computational complexity increases
Solution Approach 1:
Instead of calculating and canceling all possible non-linear order components, the system performs partial action by selectively canceling only those orders whose power values exceed a predefined threshold. This approach achieves sufficient cancellation accuracy without the excessive computational burden of processing all orders.
Solution Approach 2:
The system uses power value calculations to dynamically determine which cancellation orders to apply. By comparing power values of different order components against thresholds, the system adapts the cancellation order parameter to match the actual interference characteristics, optimizing the balance between accuracy and complexity.
3Power
If self-interference cancellation is performed at higher transmission power levels, then the benefit of FDR mode is maximized, but non-linear self-interference components become more significant and harder to cancel
Solution Approach 1:
The system performs preliminary channel estimation of the self-interference reference signal before actual data transmission. Based on this preliminary estimation, it calculates power values for different order components and establishes the appropriate cancellation order in advance, preparing the cancellation mechanism to handle high-power non-linear interference effectively.
Solution Approach 2:
The system uses feedback from power value calculations to adaptively adjust the cancellation order. By continuously monitoring the power values of different order components and comparing them against thresholds, the system feedback-adjusts which cancellation orders to apply, ensuring effective cancellation even when transmission power varies and non-linear effects become significant.
Data Source
AI summary
A method for performing self-interference cancellation (SIC) by an apparatus of a full duplex radio (FDR) mode in a wireless communication system including: performing a channel estimation of a received self-interference reference signal; calculating a power value of two order components of a non-linear self-interference signal based on the channel estimation; and establishing a non-linear digital self-interference cancellation order to be considered in the self-interference cancellation based on the power value of each for the two order components.