Abstract:

Waveform design has long been a cornerstone of wireless systems, yet its importance is being redefined in the transition from 5G to 6G and beyond. Unlike previous generational shifts, where the focus was often placed on selecting a dominant air-interface solution, the emerging 6G landscape calls for a broader and more adaptive design philosophy. High mobility, integrated sensing and communications (ISAC), non- terrestrial networking, massive machine-type connectivity, AI- native wireless systems, and holographic radio architectures are all placing new demands on the physical layer. As a result, the waveform question is no longer simply whether orthogonal frequency division multiplexing (OFDM) should be replaced, but rather how future wireless systems can support a flexible and scenario-aware waveform toolbox.