Fully utilized pilot-aided digital signal processing with state pruning MLSD assisted adaptive symbol detection for...

Area of Science:

• Optical Communications
• Digital Signal Processing
• Integrated Circuit Design

Background:

• Symbol-rate sampling in high-speed optical interconnects is crucial for reducing digital signal processing (DSP) power consumption.
• Challenges include sensitivity to analog-to-digital converter (ADC) sampling phase error and signal degradation under Nyquist constraints.
• Existing solutions often struggle with power efficiency and complexity in demanding optical interconnect applications.

Purpose of the Study:

• To propose a hardware-efficient DSP architecture for FTN-shaped 16QAM systems enabling power-efficient, symbol-rate sampled coherent optical interconnects.
• To leverage pilot-aided processing for enhanced carrier recovery and adaptive symbol detection.
• To achieve an optimal balance between bit error rate (BER) and computational complexity.

Main Methods:

• Development of a novel pilot-aided adaptive symbol detection framework (PA-SDF) incorporating state pruning maximum likelihood sequence detection (MLSD).
• Implementation of a polarization-joint misaligned pilot scheme for improved carrier recovery (CR).
• Dynamic switching between single-symbol detection (SSD) and multi-symbol detection (MSD) based on a mode-switching decision metric (MSDM).

Main Results:

• Demonstrated 0.7 dB receiver sensitivity improvement at 80/90/100 Gbaud.
• Achieved over 95% reduction in multiplier and adder usage for the carrier recovery scheme.
• Reduced MLSD complexity to 7.72% of conventional methods, with 74% of symbols processed via low-complexity SSD.

Conclusions:

• The proposed pilot-aided symbol-rate sampling DSP architecture offers a viable solution for next-generation, power-constrained data centers.
• Significant reductions in hardware complexity and power consumption were achieved.
• The architecture effectively addresses the challenges of sensitivity and signal degradation in high-speed optical interconnects.