A typical way to achieve this modeling is to generate a pseudo-random binary sequence (PRBS) by means of a LFSR (Linear Feedback Shift Register) architecture and then to decide a rule which introduces an error in the original sequence. For example you may decide that an errored bit is introduce in correspondence to a particular pattern occuring in the LFSR structure.
In this way your Eb/No is directly correlated to the probability of the occurence of your pattern in the PRBS strem, which is easily computable because a PRBS generator with enough length can be modeled by Gaussian noise.
I hope this helped enough.
Cheers
OD