frequency shifting repeater

Repeaters are usually used to extend coverage/cover blind spots.But for outdoor applications,the problem with isolation between donor and remote antennas is a problem.There is a required distance for donor and remote to prevent oscillation.

Do you think is it possible to make a repeater which receive freq A as input and shift it to frequency B as output to overcome oscillation and minimize the isolation problem?

I’m thinking that if it will be shifted,the original BCCH will now be different,and I’m not quite sure if this new BCCH can handle traffic.Although this new frequency B will be shifted back by the repeater to the original BCCH prior to sending it back to the Donor BTS.

Any Idea Pix?