This paper presents a novel multicarrier (MC) modulation method based on the linear precoded orthogonal frequency division mul- tiplexing (LP-OFDM). For linear precoding an orthogonal transform – the orthogonalized chaotic transform (OCT), which is based on the fourth or- der chaos oscillator – a modified Chua’s circuit and the Gram-Schmidt orthonormalization process, is employed. The proposed orthogonal trans- form based precoding spreads information over the whole orthogonal fre- quency division multiplexing (OFDM) signal spectrum, therefore provid- ing higher resistance to the multipath propagation and a reduction of the peak-to-average power ratio (PAPR) level in comparison with con- ventional OFDM systems. In the same time, OCT precoded signals offer a great possibility to use chaotic synchronization features for transceiver synchronization purposes as well for providing additional level of trans- mission security. Two types of the LP-OFDM systems are presented: with and without pilot signal precoding. For performance assessment of the newly proposed OCT-OFDM system, an LP-OFDM based on the well- known Walsh-Hadamard transform (WHT) is used. Baseband communi- cation system models, created using computer simulation environment, have been used in order to validate the proposed OCT-based LP-OFDM systems. As a result, the bit error rate (BER) performance over a Relay channel for all the observed LP-OFDM system models and the conven- tional OFDM model are compared. The instantaneous power comple- mentary cumulative distribution functions (CCDFs) of the waveforms, transmitted by the OFDM and the LP-OFDM systems, are explored and compared. In addition, the analysis of utilization of OCT precoding se- quences for synchronization in the LP-OFDM systems is presented.