FBMC/OQAM with OTFS Pre-Processing for High-Mobility Channels

In this paper, we proposed a new promising modulation technique called Filter-Bank Multi-Carrier with Offset Quadrature Amplitude Modulation and OTFS Pre-processing (FBMC/OQAM-OTFS) for future mobile systems. We compared the effectiveness of the proposed modulation method to others such as OFDM, OTFS, and FBMC/OQAM in terms of the shape of the signal spectrum, the bit error ratio (BER) curves in standard channel models EPA, EVA, and ETU with maximum values of the Doppler frequency ranging from 5 to 3000 Hz, and the computational complexity of signal generation. Simulation results show that the proposed modulation technique provides a very low great out-of-band emission (OOBE) level like FBMC/OQAM (for overlapping factor K = 4 it is 112.3 dB lower compared to OFDM and OTFS), and 0.7–5.6 dB gain in energy efficiency a gain in energy efficiency about 0.7–5.6 dB in considered standard channel models compared to OFDM and FBMC/OQAM. However, the computational complexity of FBMC/OQAM-OTFS is still very high (about 14 times higher than that of OFDM), but it can be reduced by 3 – 4 times by applying a poly-phase structure.