Embodiments of an OFDM transmitter and method of reducing the effects of interference on subcarriers in an OFDM system by symbol loading are disclosed herein. A linear transformation is performed on a group of two or more input data symbols that are mapped to different signal dimensions to generate a corresponding two or more output data symbols. Each of the output data symbols has an increased number of constellation points. Each output data symbol is configured for transmission within one of the different signal dimensions. The linear transformation is configured so that each of the two or more output data symbols carry the information of each of the input data symbols of the group. This coding together of input data symbols that are mapped to different signal dimensions may provide improved reliability against fading and severe interference. The different signal dimensions may comprise a frequency, a time and/or a space dimension.