Fast iterative simulation of high-speed channels via frequency-dependent over-relaxation

This paper presents an optimized Waveform Relaxation solver for electrically-long high-speed channels terminated by nonlinear networks. The time-domain scattering operators of channel and terminations are cast as recursive convolutions and nonlinear discrete-time filters, respectively. A transverse and longitudinal decoupling is then applied to the channel operator, with the introduction of suitable relaxation sources, and solved iteratively until convergence. A frequency-dependent over-relaxation parameter is introduced in order to optimize the convergence rate. Numerical results show significantly reduced runtime and iteration count for critical benchmarks with respect to previous Waveform Relaxation formulations.