Doppler-Resilient UFMC (DR-UFMC): A Beyond-OTFS Waveform for Improved Spectral Efficiency in High-Mobility Scenarios

In recent years, alternative methods to orthogonal frequency division multiplexing (OFDM) have emerged to enhance link-level performance of wireless networks in high-mobility environments. This paper introduces a new modulation technique called Doppler-Resilient Universal Filtered MultiCarrier (DR-UFMC). The goal is to merge the enhanced spectral containment of Universal Filtered MultiCarrier (UFMC) modulation with the Doppler shift resilience characteristic of Orthogonal Time Frequency Space (OTFS) modulation. Initially, we present the mathematical framework and the detailed transceiver structure for DR-UFMC modulation. Following this, a novel pilot pre-distortion approach is introduced for channel estimation, allowing the use of conventional schemes designed for OTFS modulation. An iterative method for channel estimation and data detection is also proposed, which iteratively improves the accuracy of the channel estimate and the detected symbols. The numerical evaluation compares DR-UFMC with OTFS and two versions of OFDM. The performance assessment demonstrates DR-UFMC's superior spectral containment as well as its robustness. Furthermore, both DR-UFMC and OTFS deliver comparable results concerning signal detection and channel estimation, validating the effectiveness of the proposed modulation and of the related transceiver signal processing methods.