How to filter OFDM Signal with an analog filter
same as your previous RRC question: you simply apply a digital filter that approximates the analog filter.
There's no analog signals in your PC, and OFDM is a digital signal anyway, so only the digital equivalent of the analog system would matter to the receiver, anyway.
Look at it this way: You're supposed to simulate a digital system. Therefore, the receiver is digital. Therefore, the analog effects that would happen in a real-world transceiver system are only relevant in their digital form.
And if Nyquist has taught you anything, any band-limited analog system can be represented through a digital one.
So, stop worrying about building analog filters, but describe the thing you want to simulate and then implement that digitally.
(I mean, really! Look at the purpose of OFDM: it's a purely digital thing, meant to do the inverse to a purely analog multipath channel, which is an analog filter. It works. You don't have to model anything in analog, unless you're not really understanding what OFDM is about.)