In this paper, we consider time-varying state feedback control of sing
le-input linear time-invariant discrete-time systems. The approach tha
t we propose is based on a contraction property that was introduced in
a previous paper. All time-varying controllers that yield the contrac
tion property are derived. It is seen that the state feedback vector b
ecomes m-periodic, where the integer m is a user parameter related to
the obtained contraction property. From the class of control laws that
yield the contraction property, we determine the controller which min
imizes a linear quadratic criterion. Results that are useful for tunin
g one of the user parameters are presented. Numerical examples which c
ompare the methods are also included.