  We investigate the problem of teleporting unknown qudit states via pure
quantum channels with nonmaximal Schmidt rank. This process is mapped to the
problem of discriminating among nonorthogonal symmetric states which are
linearly dependent and equally likely. It is shown that by applying an
optimized maximum-confidence (MC) measurement for accomplishing this task, one
reaches the maximum possible teleportation fidelity after a conclusive event in
the discrimination process, which in turn occurs with the maximum success
probability. In this case, such fidelity depends only on the Schmidt rank of
the channel and it is larger than the optimal one achieved, deterministically,
by the standard teleportation protocol. Furthermore, we show that there are
quantum channels for which it is possible to apply a k-stage sequential MC
measurement in the discrimination process such that a conclusive event at any
stage leads to a teleportation fidelity above the aforementioned optimal one
and, consequently, increases the overall success probability of teleportation
with a fidelity above this limit.
