A method to determine bit error rate (BER) for a given channel of a communication system includes determining a first statistical representation of at least one deterministic source of noise for the given channel. A parametric statistical representation having parameters that model non-deterministic noise is defined for the given channel and values for the parameters of the parametric statistical representation are estimated to provide a second statistical representation for the non-deterministic noise based on at least one of measurements and simulations performed for the given channel. The BER of the given channel is estimated as a function of the first and second statistical representations.