Echo Cancellation Using Segmented Adaptive Algorithm Blocks
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Solution Overview
Problem
Existing echo cancellation systems in wireless repeaters face challenges in efficiently canceling echo components near the maximum delay time without increasing the complexity and signal distortion, particularly due to the limited number of filter taps in adaptive filters.
Innovation Solution
A system and method that utilize multiple adaptive algorithm blocks with a small number of filter taps, where each block is allocated to a specific time period based on correlation operations between input and feedback signals, allowing for independent adjustment of delay times to effectively cancel echo components and fading components across multiple paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of filter taps is increased to cancel echo components near maximum delay time, then echo cancellation performance is improved, but device complexity and operation load increase
Solution Approach 1:
The patent divides the adaptive filter into multiple independent algorithm blocks, each with a small number of filter taps. Each block is assigned to handle specific echo components within its time period, allowing the system to cancel echo components near maximum delay time without requiring a single large complex filter. This segmentation resolves the contradiction by achieving comprehensive echo cancellation through multiple simple blocks rather than one complex filter.
2Reliability
If the number of filter taps is increased to cancel echo components near maximum delay time, then echo cancellation performance is improved, but signal distortion increases due to quantization noise
Solution Approach 1:
By segmenting the filter into multiple blocks with fewer taps each, the patent reduces the quantization noise impact in each individual block compared to a single large filter. Each block processes a portion of the echo components with lower computational precision requirements, thereby reducing signal distortion while maintaining overall echo cancellation effectiveness.
Solution Approach 2:
Each algorithm block is designed to handle only the echo components within its specific time period rather than processing the entire echo path. This partial action approach allows each block to use fewer filter taps, reducing quantization noise and signal distortion while the collective action of all blocks achieves complete echo cancellation.
3Device complexity
If multiple adaptive algorithm blocks with small filter taps are used, then device complexity is reduced, but the ability to cancel echo components near maximum delay time is compromised
Solution Approach 1:
The patent transitions from a single-dimension approach (one long filter) to a multi-dimensional approach (multiple blocks arranged in time periods). By organizing blocks across different time periods and assigning them to handle specific echo components, the system achieves the same echo cancellation capability as a long filter but with simpler individual blocks. This dimensional reorganization resolves the contradiction between simplicity and effectiveness.
Solution Approach 2:
The patent uses correlation operations to preliminarily identify echo components and their time periods before assigning them to specific algorithm blocks. This preliminary analysis allows each block to be optimally configured for its assigned echo components, ensuring that even with small filter taps, each block effectively cancels its designated echo components near maximum delay time.
Data Source
AI summary
A system and a method for canceling an echo is disclosed. In accordance with the system and the method, a plurality of independently and variably delayed adaptive algorithm blocks are selectively applied to a delayed feedback signal to generate a plurality of echo components in parallel, thereby canceling the echo component from an input signal.