Multiple Access Schemes for DCT-Based OFDM: Derivation and Comparison

DCT-based OFDM has been proposed as a promising multicarrier transmission scheme which, compared to the widely employed DFT-based OFDM, trades improved robustness against frequency offset for a more complex receiver implementation. However, in order to allow the introduction of DCT-based OFDM in practical systems, efficient multiple access schemes characterized by low peak-to-average power ratio (PAPR) need to be derived. In this work three different multiple access chemes for DCT based OFDM are derived and compared in terms of bit errorprobability and PAPR. These schemes have similar characteristics to corresponding DFT-based OFDMA, LFDMA and IFDMA. It is shown that, while OFDMA and LFDMA are easily adapted to DCT-based OFDM, a new multiplexing algorithm needs to be derived in case of DCT-based IFDMA. The transfer function of this novel scheme is derived and an efficient implementation is proposed which is attractive for terminal devices with limited computational capacity.