Blind Source Separation & Independent Component Analysis

[ngcmars]

Hi, I read some papers recently about the BSS & ICA.
But I still don't understand what's difference between them.
Is that means BSS need the same number of sensor and source
signal?
Another question is do we have to know about the component
prioir knowledge first? Then I can separate the mixed signal
after that proccess. It that's right?
Hope somebody can answer me, thanks.

Best wishes!!