Full-Duplex Echo Cancellation Using Intermediary Signal Processing

The patent introduces an intermediary echo canceller device positioned within the communication network that actively processes and cancels reflected signals. This intermediary component intercepts the noisy composite signal containing reflections from endpoints, splitters, and connectors, and generates cancellation signals to eliminate these harmful factors before they reach the receiver, thereby improving echo cancellation performance without requiring changes to the existing network infrastructure

The echo canceller performs preliminary processing of the transmitted signal by predicting and canceling reflections before they interfere with the received signal. The system uses training sequences and adaptive filtering to pre-characterize the network reflections and generate cancellation signals in advance, allowing the receiver to subtract these known reflection patterns from the incoming signal, thus preventing noise funneling effects from degrading communication reliability

The patent converts the harmful reflected signals and noise into beneficial cancellation information. By capturing training sequences that contain the reflection characteristics and using adaptive filtering to generate cancellation signals, the system transforms the problematic reflected energy into useful data for constructing noise profiles. These profiles are then subtracted from the received signal, effectively converting the harmful full-band noise and reflections into a benefit that improves signal quality without requiring amplifiers

The patent replaces the mechanical approach of using amplifiers to boost signal strength with a signal processing approach. Instead of physically amplifying signals to overcome losses in tree-and-branch architectures, the system uses digital signal processing techniques including adaptive filtering, training sequence analysis, and echo cancellation algorithms to computationally remove reflections and noise, thereby maintaining signal coverage without introducing the dynamic range limitations and full-band noise problems associated with analog amplification

The patent segments the frequency spectrum into manageable portions and processes reflections separately for different frequency ranges. The adaptive filter is configured with frequency-dependent coefficients that are optimized for specific frequency bands, allowing the system to handle wide frequency ranges effectively. Training sequences are analyzed to extract reflection characteristics at different frequencies, and cancellation signals are generated separately for each frequency segment, reducing the computational burden compared to processing the entire spectrum uniformly

The system dynamically adjusts parameters such as filter order, adaptation step size, and training sequence length based on the detected frequency content and reflection characteristics. When wide frequency range suppression is required, the system increases the filter order and uses longer training sequences to capture multi-frequency reflection patterns. The adaptive algorithm modifies its convergence rate and filtering parameters in real-time based on signal conditions, allowing comprehensive echo suppression while managing computational complexity through parameter optimization rather than fixed high-complexity processing