Faster-than-Nyquist signaling with non-uniform compression factors for OFDM/OQAM

This paper proposes Faster-than-Nyquist (FTN) signaling with non-uniform compression factors for orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM). In the proposed FTN signaling scheme, a compression factor lower than the average one in the assigned resource blocks (RBs) is used for the central subcarrier region, and the compression factor is increased accordingly as the subcarrier position approaches the edge in the assigned RBs. By using a compression factor close to 1 or no compression, i.e., using orthogonal multiplexing for the edge of the assigned RBs, the inter-subcarrier interference (ICI) leaked outside the assigned RBs is suppressed to a slight level. Link-level simulation results show that the FTN signaling with a non-uniform compression factor achieves almost the same average block error rate performance level as that for the FTN signaling with a uniform compression factor, while maintaining the same improvement in the frequency efficiency compared to the OFDM scheme.