It is now well understood that there is a minimal requirement on the channel quality in feedback stabilization via a communication channel. In the case of SISO plant and SISO channel. This minimal channel quality is given in terms of the degree of instability of the plant to be stabilized. For a MIMO system controlled via a MIMO communication channel, things are much less clear. In this talk, we will examine some known results and also speculate some possible directions. In the MIMO study, majorization theory plays an important role.