Orthogonal Frequency Division Multiplexing: Status, Challenges and Directions

With the convergence of communication and radar technologies, Integrated Sensing and Communication (ISAC) is expected to be a pivotal focus area for future 6G networks. Orthogonal Frequency Division Multiplexing (OFDM) technology plays a crucial role in enabling ISAC. This paper examines the fundamental principles of OFDM, its applications in terahertz ISAC systems, related advancements such as Orthogonal Time Frequency Space (OTFS), and its potential integration into future air-space-ground networks. While OFDM technology demonstrates significant promise, it also presents several challenges. To address these, researchers have proposed various enhancement strategies. This study offers valuable insights to guide the future development of OFDM technology.