OCDM System Design by iDFT Transform and 2 Phase Controllers for 6G Wireless Waveform

6G cellular communication will try to use the Sub-THz frequency band in order to provide the advanced several new services and applications including the sensing function and localization. But, the Sub-THz frequency band is not good for the wireless communication because of very high propagation loss and hostile RF(radio frequency) impairments such as phase noise disturbance of communication information signals. Therefore, a robust waveform rather than the conventional OFDM(orthogonal frequency division multiplexing) is strongly expected and the new waveform should not require too much expensive for the 6G system implementation. The OCDM(orthogonal chirp division multiplexing) is one possible candidate waveform because it has very strongly robust against the interference and the chirping technology has been used already in the RADAR application because of the very good detection and localization properties. As a result, OCDM is the attracting waveform for 6G cellular mobile communication system since OCDM is a combination waveform of chirping into the well-known OFDM system of 4G long-term evolution (LTE), 5G new radio (NR) system. However, the OCDM system design and implementation basically requires very complicated design process, and the cost will be very expensive because of the chirping process implementation based on the Fresnel transform that is more complex than the Fourier transform. In this paper, we like to show that system design of OCDM for the new 6G cellular communication system is replaced very efficiently with IDFT (Inverse Discrete Fourier Transform) and 2 phase controllers. Because the IDFT has been already used for OFDM system design, 2 phase controller addition into IDFT leads the design of OCDM, which means that this proposed OCDM does not require too much expenditure.