Double-Balanced Duplexer Leakage Cancellation for Receiver Isolation
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Solution Overview
Problem
Wireless communication devices face interference and reduced data reliability due to noise and leakage of transmission signals into receiver circuits, particularly in full duplex operations, where ideal isolation is not achieved by existing electrical components.
Innovation Solution
The implementation of auxiliary signal paths with phase and gain adjustment circuitry to provide feedback signals that cancel leakage and noise, including bandpass filters to prevent distortion, effectively isolating transmission signals from receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical components (e.g., baluns) are used to isolate transmitter from receiver, then isolation between transmission signal and receiver is provided, but less than ideal isolation is achieved due to non-ideal characteristics of real-world electrical components, leading to leakage
Solution Approach 1:
The patent implements feedback paths that sample the transmission signal and generate cancellation signals. These feedback paths include phase shifters and variable gain amplifiers that adjust the cancellation signals to match the leakage characteristics, then subtract them from the received signal to eliminate the harmful leakage effect.
Solution Approach 2:
The patent converts the harmful leakage signal into a useful cancellation signal by sampling the transmission signal through feedback paths, processing it to match the leakage characteristics, and then subtracting it from the received signal. This transforms the harmful interference into a beneficial cancellation mechanism.
2Productivity
If full duplex operations are enabled via frequency division duplexing, then data transmission and reception occur simultaneously increasing data rate, but transmission signals leak into receiver causing interference and reduced data reliability
Solution Approach 1:
The patent introduces intermediary cancellation signals that mediate between the transmission and reception paths. These signals are generated through feedback paths that sample the transmission signal, process it through phase shifters and variable gain amplifiers, and then combine it with the received signal to cancel the leakage interference, enabling reliable full duplex operation.
3Power
If power amplifier amplifies transmission signal to provide sufficient transmission power, then transmission signal reaches antenna with adequate power, but amplifier introduces noise to transmission signals in receive frequency band causing interference
Solution Approach 1:
The patent uses feedback paths to sample the amplified transmission signal and generate noise cancellation signals. The feedback paths include phase shifters and variable gain amplifiers that adjust the cancellation signals to match the noise characteristics introduced by the power amplifier, then subtract them from the received signal to eliminate the harmful noise effect.
Data Source
AI summary
Systems and method are described for improving electrical isolation between a transmission signal and receiver circuitry of a transceiver communicating over one or more wireless networks via one or more shared antennas. The transceiver may include isolation circuitry to facilitate isolation of the transmission signal from the receiver circuitry. However, a leakage current of the transmission signal and noise signals may appear at the receiver circuitry. Presence of the leakage current or the noise signals in the receiver circuitry may cause interference with the reception signal. As such, the isolation circuitry may benefit from additional isolation between the transmission signal and the receiver circuitry to reduce an effect of the leakage current and the noise signals on the reception signal.