Multi-Carrier Interference Cancellation via Digital Pre-Distortion
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Solution Overview
Problem
Current duplexer designs in multi-carrier base station transceivers face challenges in effectively suppressing high-order intermodulation interference, leading to increased size and complexity, which is exacerbated by the need for high suppression degrees and limited capabilities of existing digital pre-distortion methods.
Innovation Solution
A method and apparatus that collect high-order intermodulation signals, process them to generate digital signals, and use a high-order intermodulation model to counteract interference by pre-distorting radio frequency signals in a time-division manner, reducing the requirements on duplexer suppression and simplifying duplexer design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a duplexer uses multiple filter cavities to achieve high suppression degree (111 dB), then the suppression of intermodulation interference is improved, but the size of the duplexer increases significantly
Solution Approach 1:
The patent replaces the mechanical/filter-based suppression approach with a digital signal processing approach. A digital filter processes the received signal to remove intermodulation interference components, substituting complex physical filter cavities with software-based filtering algorithms that achieve the same suppression effect without increasing hardware size
Solution Approach 2:
The patent introduces a digital filter as an intermediary component between the receiver and the signal processing chain. This digital filter acts as a mediator that selectively removes intermodulation interference frequencies from the received signal, enabling high suppression degree without requiring additional physical filter cavities in the duplexer
2Device complexity
If digital pre-distortion is used to reduce intermodulation, then the complexity of duplexer design is reduced, but the method cannot effectively cancel high-order intermodulation interference
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is processed through a digital filter to identify and characterize intermodulation interference components. This feedback information is then used to continuously optimize the pre-distortion parameters, enabling the system to effectively cancel high-order intermodulation interference while maintaining simple duplexer design
Solution Approach 2:
The patent enhances the pre-distortion technique by performing preliminary analysis of the received signal to identify intermodulation components before applying cancellation. This preliminary action allows the system to proactively adjust pre-distortion parameters to prevent high-order intermodulation interference, combining the simplicity of pre-distortion with effective high-order interference cancellation
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AI summary
A method, an apparatus, and a transceiver for cancelling multi-carrier transmission interference are provided. The method includes: collecting a high order intermodulation signal in radio frequency signals output by a transmitter; processing the high order intermodulation signal so as to generate a first digital signal; establishing a high order intermodulation model by using the first digital signal and a first baseband signal output by the transmitter; generating a second digital signal by using a coefficient of the high order intermodulation model and a second baseband signal output by the transmitter; and counteracting interference in a digital signal output by a receiver with the second digital signal. By using the present invention, high order intermodulation interference of a multi-carrier transmitter on a receiver can be effectively canceled, and therefore, difficulty in duplexer design and requirements on a suppression degree are reduced.