Wavelet‐Aided OTFS With Improper Gaussian Noise

Sixth‐generation (6G) wireless communication is expected to include much higher mobility usage scenarios compared with previous generations. This situation brings with it challenges such as Doppler and hardware‐induced distortion effects, which traditional methods are insufficient to handle. In this study, wavelet‐aided orthogonal time‐frequency space (W‐OTFS) modulation, known for its resistance to Doppler shifts, is addressed under the effect of improper Gaussian noise (IGN) originating from hardware faults, which is largely neglected in the literature. Considering a highly mobile 6G scenario, a hard‐decision‐based widely linear minimum mean square error (WL‐MMSE) detector is designed to evaluate the bit error rate (BER) of the proposed W‐OTFS system, and the simulation results are presented. In addition to Daubechies and Haar wavelets, which are frequently preferred in W‐OTFS applications, results obtained with different orthogonal wavelet types are also introduced. The extensive simulation results demonstrate that the W‐OTFS provides more than 5 dB gain for achieving a BER value of compared with the traditional OTFS, regardless of the wavelet type. Furthermore, W‐OTFS is proven to resolve the high PAPR issue in OTFS. Depending on the selected wavelet type, a minimum PAPR reduction of 2.5 dB was achieved compared with OTFS.