CMR Combining for Echo Cancellation in Full-Duplex Cable Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solutions for echo cancellation in uplink communications, particularly in cable-based networks, are costly, inefficient, and ineffective, limiting bandwidth and increasing infrastructure costs due to shared channel capacity between transmit and receive paths.
Innovation Solution
The implementation of common mode rejection (CMR) for echo cancellation in full-duplex (FDX) based systems, which allows simultaneous transmission and reception in the same spectrum, using a CMR combiner to mitigate echo effects by combining signals in a non-coherent manner and applying compensation signals to cancel undesired transmitted signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional echo cancellation methods are used in uplink communications, then echo suppression is achieved, but system cost increases and infrastructure complexity increases
Solution Approach 1:
The patent converts the harmful echo signal into a beneficial component by using the transmitted signal itself as the reference for cancellation. The CMR combiner utilizes the known transmitted signal to generate a cancellation signal that subtracts the echo from the received uplink signal, transforming the problematic echo into a useful reference for achieving cancellation without requiring complex external infrastructure.
Solution Approach 2:
The patent creates a copy of the transmitted signal to serve as a reference for echo cancellation. By copying the known transmitted waveform and processing it through the CMR combiner, the system generates an accurate representation of the echo path that can be subtracted from the received signal, eliminating the need for complex physical echo path characterization infrastructure.
2Device complexity
If shared channel capacity is used between transmit and receive paths, then infrastructure cost is reduced, but bandwidth is limited
Solution Approach 1:
The patent enables continuous full-duplex operation on the same shared infrastructure by implementing real-time echo cancellation. The CMR combiner continuously processes the received signal to cancel the transmitted signal's echo, allowing both transmit and receive paths to operate simultaneously on the shared channel without interference, thereby maximizing the utilization of the available bandwidth.
3Productivity
If full-duplex communication is implemented in the same spectrum, then spectrum utilization is enhanced, but echo cancellation performance is degraded without proper mitigation
Solution Approach 1:
The patent introduces the CMR combiner as an intermediary component that mediates between the transmitted signal and the received uplink signal. This intermediary processes the transmitted signal to generate an accurate echo model and subtracts it from the received signal, effectively eliminating echo effects and enabling clear full-duplex communication in the same spectrum.
Data Source
AI summary
Systems and methods are provided for use of common mode rejection (CMR) for echo cancellation in uplink communications. A node in a cable network configured for transmitting downstream (DS) signals and receiving upstream (US) signals, may include echo cancelling circuits configured for cancelling echo introduced by the DS signals and/or transmittal of the DS signals, onto US signals and/or US reception path, to facilitate full-duplex (FDX) communications of the DS signals and US signal. The echo cancelling circuits may be configured for operating in the analog domain. The echo cancelling circuits may include an echo cancelling combiner configured for combining two or more upstream signals non-coherently.