Wavelet-Aided OTFS: A 2D Multicarrier Modulation Format for High-Mobility Communications

Abstract

This article proposes a wavelet-aided orthogonal time-frequency space (W-OTFS) modulation as a novel approach for high-mobility vehicular communication. Leveraging the advantages of discrete wavelet transforms, W-OTFS provides improved performance over existing orthogonal time-frequency space (OTFS) modulation in doubly selective vehicular channels. The system exhibits a direct correspondence between input and output through matrix multiplication and primarily employs a minimum mean square error (MMSE) based linear detector for signal detection. This study investigates Haar and Daubechies wavelets for the transformation and we observe that wavelets of lower-order enhance channel sparsity and reduce computational complexity. A soft-decision-based iterative detector is proposed to improve the system’s performance further. The results of our simulations demonstrate that W-OTFS utilizing the soft-decision detector can achieve a bit-error rate (BER) of 10−5 in the regions of low signal-to-noise ratio (SNR). Moreover, W-OTFS outperforms conventional OTFS in terms of peak-to-average power ratio (PAPR) and the complexity of modulation and demodulation processes.