IIR Filter Receiver Reduces Error Propagation
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Solution Overview
Problem
Conventional communication signal receivers face challenges with error propagation and increased system complexity due to the use of decision feedback equalizers, which affect the performance of Viterbi decoders and require complex parameter adjustments.
Innovation Solution
A communication signal receiver employing an infinite impulse response (IIR) filter to replace the conventional feedback equalizer, coupled with a slicer and adder to process signals, allowing for simpler decoder operation and reduced complexity by using a Viterbi decoder with a selector to manage signal inputs during convergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a decision feedback equalizer (DFE) is used to cancel post-cursor components, then signal equalization is improved, but error propagation occurs and system complexity increases
Solution Approach 1:
The patent changes the fundamental parameter of the equalization approach by replacing the decision feedback equalizer with an infinite impulse response (IIR) filter. This parameter change transforms the equalization mechanism from one that uses decision-based feedback to one that uses a continuous impulse response filter, thereby eliminating error propagation while maintaining equalization effectiveness and reducing overall system complexity
Solution Approach 2:
The patent extracts and removes the problematic decision feedback component from the equalizer structure. By taking out the decision feedback mechanism that causes error propagation, the system retains the beneficial equalization function through the IIR filter while eliminating the harmful error propagation effect
2Device complexity
If a Viterbi decoder is directly connected to the output of the DFE, then decoding is simplified, but decoding capability is deeply affected by error propagation
Solution Approach 1:
The patent changes the input signal parameter to the Viterbi decoder by using the IIR filter output instead of the DFE output. This parameter change ensures that the decoder receives a signal free from error propagation, thereby maintaining both decoding simplicity and high decoding capability
3Reliability
If a decision feedback sequence estimator (DFSE) is used to detect data from the DFE, then error propagation is decreased, but system complexity increases significantly
Solution Approach 1:
The patent extracts and removes the complex DFSE component entirely from the system. By taking out the DFSE and its associated parameter adjustment mechanisms, the system achieves error propagation reduction through the simpler IIR filter approach, thereby improving reliability while significantly reducing system complexity
Data Source
AI summary
A communication signal receiver includes an adder, a slicer, and an infinite impulse response (IIR) filter. The adder performs an addition on a first signal and a filtered signal to generate an output signal. The slicer performs a hard decision on the output signal to generate a detecting result. The IIR filter is coupled to the slicer and the adder for processing the output signal to generate the filtered signal. The communication signal receiver further includes a decoder. The decoder receives and decodes the output signal to generate a decoded output signal, wherein the decoder is a Viterbi decoder.