You should look into some existing real-time ICA implementation (I don't have any at hand and don't know enough about the algorithm to know whether it's possible / it makes sense) and/or implement it yourself. There is nothing Bela-specific about the way yo'd implement such an algorithm. Once you have a real-time implementation in C or C++, then plugging it into Bela should be the least of the concerns. It may need some tweaking about expected block size for block-based operation and/or to accommodate occasional, expensive computations.
