Reception Device Linear Nonlinear Equalization Channel Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional adaptive nonlinear equalizers face challenges in calculating filter coefficients when the number of coefficients exceeds the number of symbols in a known signal, leading to incomplete channel estimation.
Innovation Solution
A reception device with an equalization processing unit comprising both linear and nonlinear filters, a linear propagation channel estimation unit, and a synchronization processing unit, which performs an initial equalization process using linear filter coefficients and subsequently an adaptive equalization process combining outputs from both filters, allowing for filter coefficient calculation even with fewer known signal symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of filter coefficients is increased to improve channel estimation accuracy, then the equalization performance is improved, but the number of known signal symbols required increases
Solution Approach 1:
The patent segments the equalization process into two distinct phases: a first equalization process using only a linear filter with filter coefficients calculated from known signal symbols, and a second equalization process using both linear and nonlinear filters where the nonlinear filter coefficients are calculated from data symbols. This segmentation allows the system to achieve high channel estimation accuracy with a small number of known signal symbols by performing linear equalization first, then refining the estimation using nonlinear equalization on data symbols.
Solution Approach 2:
The patent performs preliminary linear equalization using filter coefficients calculated from known signal symbols before performing nonlinear equalization. This preliminary action prepares the signal by removing linear distortions, enabling subsequent nonlinear equalization to focus on correcting nonlinear distortions with fewer additional symbols, thereby reducing the total number of known signal symbols required.
2Reliability
If a conventional adaptive nonlinear equalizer is used to calculate filter coefficients, then both linear and nonlinear distortion can be compensated, but the calculation cannot be performed when the number of filter coefficients exceeds the number of known signal symbols
Solution Approach 1:
The patent divides the filter coefficient calculation into two separate processes: linear filter coefficients are calculated from known signal symbols in the first equalization process, while nonlinear filter coefficients are calculated from data symbols in the second equalization process. This segmentation enables the system to operate reliably even when the number of known signal symbols is smaller than the total number of filter coefficients, as long as there are sufficient data symbols available.
Solution Approach 2:
The system performs preliminary calculation of linear filter coefficients using known signal symbols before calculating nonlinear filter coefficients using data symbols. This preliminary action ensures that linear distortion compensation is established first, creating a foundation that enables subsequent nonlinear equalization to proceed even with limited known symbols.
Data Source
AI summary
A reception device includes an equalization processing unit including a linear filter unit and a nonlinear filter unit and performing equalization process on a reception signal; a linear propagation channel estimation unit making propagation channel estimation using a known signal included in a reception signal to calculate a filter coefficient of the linear filter unit; and a synchronization processing unit performing synchronization process of correcting frequency deviation based on a signal output by the equalization processing unit, and when a predetermined condition is satisfied after executing first equalization process of outputting a reception signal filtered by the linear filter unit to the synchronization processing unit, the equalization processing unit starts second equalization process that is an adaptive equalization process of outputting a result of addition of a reception signal filtered by the linear filter unit and a reception signal filtered by the nonlinear filter unit to the synchronization processing unit.