Full Duplex Transceiver Leakage Cancellation via Auxiliary Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Full duplex transceivers face significant challenges with self-interference due to transmission leakage, which is exacerbated by the close proximity of transmission and reception circuitry in smaller device designs, leading to distortion and interference in received signals.
Innovation Solution
The implementation of an auxiliary receiver and transmitter within the transceiver, which processes the received signal to determine transmission leakage and generates a cancellation signal to be added back to the signal, effectively canceling out the interference through a feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If transmission circuitry is placed closer to reception circuitry to reduce device size, then device miniaturization is achieved, but transmission leakage into reception signal increases
Solution Approach 1:
The patent implements a feedback mechanism where the transmitted signal is fed back through the transmission circuitry to the reception circuitry, allowing the system to measure and compensate for leakage effects. The feedback loop enables adaptive cancellation of transmission leakage by continuously monitoring and adjusting based on actual leakage conditions.
Solution Approach 2:
The patent converts the harmful transmission leakage signal into a useful cancellation reference signal. By feeding back the transmitted signal through the same transmission circuitry, the system creates a replica of the leakage that can be used to generate an equal and opposite cancellation signal, thereby transforming the harmful interference into a beneficial reference for leakage compensation.
2Object-affected harmful factors
If duplexer isolation is increased to reduce transmission leakage, then reception signal quality improves, but device complexity increases
Solution Approach 1:
The patent uses feedback from the transmitted signal to dynamically adjust and compensate for leakage effects, replacing the need for high fixed isolation in the duplexer. The feedback loop continuously monitors leakage and applies cancellation signals, achieving effective leakage reduction without requiring overly complex isolation mechanisms.
Solution Approach 2:
The patent changes the operational parameters of the reception circuitry by introducing cancellation signals that dynamically adjust the signal processing characteristics. This allows the system to adapt to varying leakage conditions by modifying signal parameters rather than relying on fixed hardware isolation settings.
3Object-affected harmful factors
If active cancellation is implemented to reduce transmission leakage, then reception signal quality improves, but device complexity increases
Solution Approach 1:
The patent converts the transmitted signal, which would normally be considered interference, into a useful reference signal for cancellation. By feeding back the transmitted signal through the transmission circuitry, the system creates a precise replica that can be used to generate cancellation signals, transforming the interference problem into a solution opportunity.
Solution Approach 2:
The feedback loop in the patent provides continuous information about the actual leakage conditions, enabling adaptive cancellation. The system uses the feedback signal to adjust cancellation parameters in real-time, improving effectiveness while keeping the cancellation circuitry more efficient through adaptive rather than fixed-parameter operation.
Data Source
AI summary
A full duplex transceiver has cancellation circuitry that includes an auxiliary receiver and an auxiliary transmitter. More specifically, an analog received signal that includes transmission signal leakage is provided to a low noise amplifier (LNA), which then provides its output to a main receiver and the auxiliary receiver. The auxiliary receiver includes a portion operable to convert the received signal from the analog domain to the digital domain. The auxiliary receiver additionally includes a cancellation processor that determines the transmission signal leakage and generates a signal based on the determined leakage. This signal generated by the auxiliary receiver is provided to the auxiliary transmitter, which converts the digital signal back to the analog domain and generates a cancellation signal. The analog cancellation signal is fed back and added to the received signal at the input of the LNA. As a result of the feedback system including an auxiliary receiver and an auxiliary transmitter, transmission signal leakage of many types may be canceled from a received signal.