Multi-Valued Data Transmission System Using Mild Waveform Shaping Based on Multi-Dimensional Symbol Mapping

In high-speed data communication, inter-symbol interference (ISI), arising from the low-pass characteristics of transmission lines, introduces significant challenges. To address this issue, we propose a multi-dimensional symbol mapping-based approach for mild waveform shaping, enabling effective ISI visualization and reduction. We demonstrate a method to analyze and mitigate both pre-cursor and post-cursor ISI using two-dimensional (2D) and three-dimensional (3D) symbol mapping techniques. Our approach alleviates the need for transmitter-side feed-forward equalizer (FFE) processing by tolerating the controlled ISI at the receiver, aligning the post-cursor ISI with exponential decay curves. This alignment ensures symbol separability on the symbol map, even in conditions where conventional evaluations using eye diagrams fail. Furthermore, 3D symbol mapping extends this methodology to visualize the pre-cursor ISI through rotational and projection transformations. Simulations with PAM-4 data transmission systems verify the efficacy of this method in a microstrip line environment, achieving reduced ISI effects and improved signal integrity.