Two-Stage Signal Equalization for ISI and Multipath Complexity
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Solution Overview
Problem
Existing communication systems face challenges in fully utilizing signal energy while reducing inter-symbol interference (ISI) without increasing noise, particularly with increasing multipath channel lengths, which complicates Viterbi equalizers.
Innovation Solution
An equalization device and method incorporating a predictive decision feedback equalizer, serial-to-parallel converter, and equalization module that transforms and equalizes received signals to generate transformed sequences, effectively utilizing signal energy and reducing operational complexity by equivalent channel length reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a Viterbi equalizer is used to fully utilize signal energy, then signal energy utilization is improved, but device complexity increases exponentially with multipath channel length
Solution Approach 1:
The patent segments the equalization process into two stages: a first equalizer (such as a decision feedback equalizer) that handles initial equalization and noise reduction, followed by a second equalizer (such as a Viterbi equalizer) that processes the already-conditioned signal. This segmentation allows the complex Viterbi equalizer to operate on a pre-processed signal, reducing its computational burden while maintaining full signal energy utilization.
Solution Approach 2:
The patent applies preliminary equalization actions before the main Viterbi equalization process. The first equalizer performs preliminary signal conditioning, including interference cancellation and noise reduction, which prepares the signal for more efficient processing by the subsequent Viterbi equalizer, thereby reducing the overall complexity while maintaining energy utilization.
2Reliability
If a linear feed-forward equalizer is used, then equalization is achieved, but noise is increased
Solution Approach 1:
The patent employs feedback mechanisms in the form of decision feedback equalizers where the detected symbols are fed back to cancel out intersymbol interference from previous symbols. This feedback approach allows for equalization without the noise amplification problem inherent in linear feed-forward equalizers, as the feedback path uses already-decoded information to subtract interference rather than amplify noise.
3Object-generated harmful factors
If a decision feedback equalizer is used to eliminate ISI without increasing noise, then noise level is maintained, but signal energy cannot be fully utilized
Solution Approach 1:
The patent merges the advantages of different equalizer types by combining a decision feedback equalizer (which maintains low noise levels) with a Viterbi equalizer (which fully utilizes signal energy). The combined approach uses the decision feedback equalizer first to eliminate ISI without noise increase, then feeds the result to the Viterbi equalizer which maximizes energy utilization, thereby achieving both low noise and high energy efficiency simultaneously.
Data Source
AI summary
An equalization device is arranged for equalizing a received signal, wherein the received signal may include a primary signal and at least one interference signal. The equalization device may include a transformation module, a serial-to-parallel converter, and an equalization module, wherein the transformation module may include a predictive decision feed-back equalizer, a first feed-back filter and an adder. The transformation module is arranged for generating a transformation signal according to the primary signal and the at least one interference signal of the received signal, wherein the transformation signal includes a transformed primary signal and at least one transformed interference signal. The serial-to-parallel converter is arranged for respectively converting the transformed primary signal and the transformed interference signal into a plurality of transformation signal sequences. The equalization module is arranged for respectively equalizing the plurality of transformation signal sequences so as to generate a plurality of equalized sequences.