  In this paper, achievable rates of imperfectly-known fading relay channels
are studied. It is assumed that communication starts with the network training
phase in which the receivers estimate the fading coefficients of their
respective channels. In the data transmission phase, amplify-and-forward and
decode-and-forward relaying schemes are considered, and the corresponding
achievable rate expressions are obtained. The achievable rate expressions are
then employed to identify the optimal resource allocation strategies.
