Importance sampling for simulation of communication systems with adaptive equalizers

An importance sampling (IS) methodology for Monte Carlo simulation of communication links characterized by time-varying channels and adaptive equalizers is presented. This methodology is denoted the twin system (TS). A key feature of the TS is that biased noise samples are input to the adaptive equalizer, but the equalizer is only allowed to adapt to these samples for a time interval equal to the memory of the system. Experimental results are presented that show runtime speed-up factors of three to six orders of magnitude for a static linear channel with memory, and of four to nine orders of magnitude for a slowly varying, random linear channel with memory