  The coexistence of different wireless communication systems such as LTE and
Wi-Fi by sharing the unlicensed band is well studied in the literature. In
these studies, various methods are proposed to support the coexistence of
systems, including listen-before-talk mechanism, joint user association and
resource allocation. However, in this study, the coexistence of different
waveform structures in the same resource elements are studied under the theory
of non-orthogonal multiple access. This study introduces a paradigm-shift on
NOMA towards the application-centric waveform coexistence. Throughout the
paper, the coexistence of different waveforms is explained with two specific
use cases, which are power-balanced NOMA and joint radar-sensing and
communication with NOMA. In addition, some of the previous works in the
literature regarding non-orthogonal waveform coexistence are reviewed. However,
the concept is not limited to these use cases. With the rapid development of
wireless technology, next-generation wireless systems are proposed to be
flexible and hybrid, having different kinds of capabilities such as sensing,
security, intelligence, control, and computing. Therefore, the concept of
different waveforms' coexistence to meet these concerns are becoming impressive
for researchers.
