The point is to find this Documents of prior Art on Universitys Like Berkley or MIT
http://www.informatik.uni-trier.de/~...harles_N=.html
Charles N. Lo, Henri E. Tohme, Richard S. Wolff: A Hybrid Architecture for Analog Video Broadcast and B-ISDN Services in Customer Premises Networks. IEEE Journal on Selected Areas in Communications 8(7): 1327-1339 (1990)
So there IS some docs the problem is only to find them.