On improving the computational efficiency of digital lightwave link simulation

It is noted that although bit error rate (BER) analysis of an end-to-end digital lightwave link using simulation is feasible, further reduction in execution time is needed when the link includes an APD (avalanche photodetector) receiver. The authors present techniques that reduce the computational resources required to estimate the BER for these systems by at least two orders of magnitude. They achieve the speedup by developing a more efficient random number generation algorithm for APD shot noise and applying a tail extrapolation technique to the BER conditional distributions. Receiver thermal noise is handled analytically. Simulation results are presented which demonstrate that accurate estimates of the BER for a typical lightwave communications link can be obtained in approximately 1.5 CPU hours on a VAXstation II using a combination of these approaches