In OFDM transmission, it is possible to adoptively control transmission scheme of each sub-carrier according to the transmission channel because each sub-carrier in OFDM is orthogonally arranged in frequency domain. Although this sub-carrier independent adaptive modulation scheme is very efficient, it is necessary to transmit allocation information of modulation scheme, coding scheme and so on. In order to reduce transmission of extra information, use of a pre-coded OFDM transmission is very effective[1]. In this paper, adaptive determination of modulation scheme and coding rate of pre-coded OFDM transmission is proposed in order to improve transmission under power-line channels.