Full-Duplex Self-Interference Cancellation via Pre-Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In communication systems supporting full-duplex schemes, existing self-interference cancellation methods face challenges in effectively reducing the number of self-interference signals, especially when using multiple input multiple output (MIMO) techniques, due to complexities in predicting and canceling signals with random delay times, amplitudes, and phases.
Innovation Solution
The proposed solution involves an apparatus and method for self-interference cancellation using a pre-filtering scheme in conjunction with analog and digital signal processing, which estimates channel information for both wired and wireless channels to configure multiple analog SIC circuits that adjust gain, phase, and delay to cancel a variety of self-interference signals, and applies a pre-filtering operation to concentrate power and reduce the number of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple analog SIC circuits are used to cancel various self-interference signals with random delay times, amplitudes, and phases, then the cancellation effectiveness is improved, but the device complexity increases
Solution Approach 1:
The patent applies pre-filtering to the transmission signal before it is transmitted, which concentrates the signal power and reduces the number of self-interference signal components. This preliminary action simplifies the subsequent cancellation task, allowing fewer analog SIC circuits to achieve effective cancellation while reducing overall system complexity
Solution Approach 2:
The patent divides the self-interference cancellation process into two stages: pre-filtering (concentrating power and reducing signal components) and analog SIC (canceling remaining interference). This segmentation allows each stage to focus on specific aspects, improving overall efficiency while managing complexity
2Device complexity
If pre-filtering is applied to concentrate power and reduce the number of self-interference signals, then the device complexity is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent uses feedback mechanisms where the receiver estimates channel information and feeds it back to the transmitter. The transmitter then configures the pre-filter based on this feedback, creating a closed-loop system that continuously optimizes the filtering parameters to maintain precision while reducing complexity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present disclosure relates to a pre-5th-generation (5G) or 5G communication system to be provided for supporting higher data rates beyond 4th-generation (4G) communication system such as a long term evolution (LTE). A method for cancelling a self-interference (SI) signal in a communication system supporting a full-duplex scheme is provided. The method includes estimating an SI channel, performing a pre-filtering operation on a transmission signal based on the estimated SI channel, generating copied-SI signals based on the estimated SI channel, and cancelling an SI signal based on the copied-SI signals, wherein the pre-filtering operation includes an operation for decreasing a number of SI signals.