Relay Apparatus Self-Interference Cancellation
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Solution Overview
Problem
In relay base station apparatuses, signal interference occurs when one antenna receives a signal intended for another, leading to deteriorated reception quality.
Innovation Solution
A wireless relay apparatus with a transmission circuit to amplify and transmit signals, a reception circuit to receive mixed signals, and a processor performing cancellation processing, including generating cancellation signals to isolate and remove interference, thereby improving signal reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a relay base station apparatus uses two antennas for wireless communication, then communication coverage and capacity are improved, but signal interference occurs when one antenna receives a signal transmitted from the other antenna
Solution Approach 1:
The patent captures the transmitted signal from one antenna using the other antenna (which would normally be considered interference or harmful), and then uses signal processing techniques to extract and utilize this signal for improving overall communication performance. The harmful self-interference is converted into a useful signal source for diversity combining or MIMO operations.
Solution Approach 2:
The patent changes the phase of the transmitted signal to generate a cancellation signal that opposes the interfering signal. By adjusting phase parameters and combining signals constructively, the system eliminates the harmful interference while maintaining the benefits of dual-antenna operation.
2Device complexity
If the relay base station apparatus receives a signal from the other antenna as noise, then the system structure remains simple, but the reception quality of the signal from the base station apparatus deteriorates
Solution Approach 1:
The patent introduces an intermediary signal processing stage that mediates between the transmitted and received signals. A cancellation signal is generated as an intermediary element that bridges the transmitted signal and the received mixed signal, allowing the system to separate and eliminate the interfering component while preserving the desired signal.
Solution Approach 2:
The patent changes the phase parameter of the transmitted signal to create a cancellation signal that is 180 degrees out of phase with the interfering signal. This parameter transformation allows the harmful signal to be converted into a beneficial cancellation component without requiring complex structural modifications.
3Reliability
If cancellation processing is performed to remove the transmitted signal from the received mixed signal, then reception quality is improved, but processing complexity increases
Solution Approach 1:
The patent performs preliminary phase adjustment on the transmitted signal before it becomes interference in the received signal. By pre-modifying the phase of the transmitted signal to create a predictable cancellation pattern, the system simplifies the subsequent cancellation processing and reduces the computational complexity of removing the interference.
Solution Approach 2:
The patent applies parameter changes to the transmitted signal phase to facilitate easier cancellation. By transforming the phase parameter in a controlled manner, the cancellation processing becomes more straightforward and computationally efficient, reducing the overall processing complexity while maintaining effective interference removal.
Data Source
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AI summary
An apparatus for relaying wireless communications between a first apparatus and a second apparatus includes: a transmitter to amplify power of a first signal and transmit of the first signal to the first apparatus; a receiver to receive a mixed signal including a second signal from the second apparatus and the first signal transmitted from the transmitter; and a processor to perform a process for canceling the first signal out of the mixed signal, the process including generating a first cancellation signal having a phase changed from a phase of the first signal to be transmitted, generating a composite signal by combining the first cancellation signal with the mixed signal, extracting a difference between the composite signal and the first signal to be transmitted, generating a second cancellation signal based on the extracted difference, and generating a cancelled signal produced by combining the second cancellation signal with the composite signal.