Full Duplex Self-Interference Cancellation via Analog-Digital Segmentation
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Solution Overview
Problem
Existing full duplex communication systems face reduced self-interference cancellation performance due to non-linearity of power amplifiers, which affects the channel capacity and signal quality.
Innovation Solution
A self-interference cancellation control method and device that utilizes both analog and digital cancellation units to measure and cancel interference signals, with the analog unit setting values based on impulse response and the digital unit estimating remaining interference using a pilot signal, thereby separating and canceling non-linear components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If analog self-interference cancellation is used, then self-interference cancellation performance is improved, but distortion of transmitted signal due to power amplifier non-linearity increases
Solution Approach 1:
The patent divides the self-interference cancellation process into two distinct segments: analog cancellation and digital cancellation. The analog cancellation unit handles the primary self-interference cancellation in the analog domain, while the digital cancellation unit processes the remaining interference and compensates for non-linear distortion in the digital domain. This segmentation allows each unit to specialize in handling specific aspects of interference cancellation, thereby improving overall performance while managing signal distortion.
Solution Approach 2:
The patent introduces a digital cancellation unit as an intermediary between the analog cancellation unit and the final signal processing stage. This digital unit receives the down-converted signal, estimates remaining interference using pilot signals, and compensates for non-linear distortion. The intermediary digital processing stage acts as a mediator that corrects the distortion introduced by the power amplifier while preserving the benefits of analog cancellation.
2Power
If power amplifier non-linearity is increased, then transmitted signal amplification is improved, but self-interference cancellation performance deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the digital cancellation unit uses pilot signals to estimate the channel characteristics and remaining self-interference. This estimated information is fed back to adjust and optimize the cancellation process. The feedback loop enables the system to adapt to power amplifier non-linearity by continuously monitoring and compensating for distortion, thereby maintaining self-interference cancellation performance even when amplification is increased.
Solution Approach 2:
The patent employs parameter changes in the digital domain to compensate for non-linear effects. By adjusting digital signal processing parameters such as filter coefficients and cancellation weights based on pilot signal measurements, the system can adapt to varying power amplifier characteristics. This allows the system to maintain optimal self-interference cancellation performance across different amplification levels despite power amplifier non-linearity.
Data Source
AI summary
This application relates to a full duplex communication device. In one aspect, the device includes a transmission/reception antenna configured to receive a received signal corresponding to a transmitted signal. The device may also include an analog cancellation unit configured to set values of elements constituting an analog cancellation circuit and cancel an interference signal included in the received signal using the set values of the elements constituting the analog cancellation circuit. The device may further include a digital cancellation unit configured to cancel a remaining interference signal included in the received signal. Some embodiments can minimize the influence of distortion of a transmitted signal due to non-linearity of a power amplifier during an active analog self-interference cancellation process.