Robust pole placement in discrete-time systems

The problem of robust pole placement via a state-space feedback is discussed for discrete-time systems. It is assumed that a discrete-time system is described in terms of the state-space equation x(k+1)=Ax(k)+bu(k),y(k)=c^Tx(k)+eu(k) with uncertain entries of matrices (c, A, b,e). A feedback matrix f is calculated such that the real stability radius of the characteristic polynomial of the closed-loop system is possibly maximal.