Implementing this in Matlab is rather simple, but you need to figure out what formulas that you want to implement. First, you need to a channel model for the MIMO cases (for which the SISO case is a special case). Is it a deterministic or random channel? If they are random, what is the distribution. What is the SNR? Next, you need to connect the channel model to the frequency. Basically, you need to figure out the reason for the frequency dependency.
Implementing this in Matlab is rather simple, but you need to figure out what formulas that you want to implement. First, you need to a channel model for the MIMO cases (for which the SISO case is a special case). Is it a deterministic or random channel? If they are random, what is the distribution. What is the SNR? Next, you need to connect the channel model to the frequency. Basically, you need to figure out the reason for the frequency dependency.