PDLUT Pre-Compensation With Quantized FIR Correction
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Solution Overview
Problem
Conventional Pattern Dependent Lookup Table (PDLUT) methods for signal pre-compensation in high baud-rate optical communications require high computational complexity and power consumption, exceeding the limits set by strict standards for ultra-high-speed applications like Data Center Interconnects.
Innovation Solution
A low-complexity and low-power PDLUT pre-compensation method using quantized distortion correction values and multiple FIR filters to reduce computational steps and power consumption, achieved through a two-stage quantization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PDLUT methods use long-bit resolution distortion correction values (8 bits or longer), then accurate distortion correction is achieved, but calculation complexity and power consumption significantly increase
Solution Approach 1:
The distortion correction value is segmented into multiple portions (first portion and second portion), each processed by separate FIR filters with different numbers of input levels. This segmentation allows each filter to operate with reduced computational complexity while maintaining overall correction accuracy.
Solution Approach 2:
Different portions of the distortion correction value are processed with different levels of precision. The first portion is processed by an FIR filter with a first number of input levels, while the second portion is processed by an FIR filter with a second number of input levels, optimizing the balance between accuracy and power consumption for each portion.
2Measurement precision
If conventional PDLUT methods use long-bit resolution distortion correction values (8 bits or longer), then accurate distortion correction is achieved, but the number of computational steps increases
Solution Approach 1:
The distortion correction computation is divided into multiple independent FIR filter operations, each handling a specific portion of the correction value with a tailored number of input levels, reducing the overall computational burden compared to a single high-precision filter.
Solution Approach 2:
Each portion of the distortion correction value is processed with locally optimized precision levels, where the first portion uses an FIR filter configured with a first number of input levels and the second portion uses an FIR filter with a second number of input levels, minimizing unnecessary computational steps.
3Use of energy by stationary object
If ultra-high-speed transceiver modules (800Gbps and beyond) operate with strict power consumption standards, then compliance with standards is achieved, but DSP algorithm performance is limited
Solution Approach 1:
The system changes the parameter of input levels for the FIR filters based on the specific portion of the distortion correction value being processed. By dynamically adjusting the number of input levels for each filter, the system achieves power consumption compliance while maintaining sufficient DSP algorithm performance for ultra-high-speed applications.
Data Source
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AI summary
Methods and systems for performing signal pre-correction of a transmission signal comprising a sequence of symbols using a Pattern Dependent Look-up Table (PDLUT) containing one or more distortion correction values. Upon accessing a distortion correction value from the PDLUT for a symbol of the sequence of symbols, the accessed distortion correction value is quantized into one or more quantized values according to one or more quantizations, thereby reducing the bit-width of the distortion correction value. The transmission signal and the distortion correction value with reduced bit-width may undergo linear correction compensation, such as through a finite impulse response (FIR) filter, independent of one another, where the one or more quantized correction values with reduced bit-width reduce a number of calculation steps performed during linear correction compensation resulting in power savings. The linearly compensated quantized values and the linearly compensated signal are combined to form a pre-corrected signal.