Two-Dimensional Discrete Cosine Transform OFDM Waveform for 6G: Operation and Implementation

In this paper, a novel modulation scheme called two-dimensional discrete cosine transform orthogonal frequency-division multiplexing (2D-DCT-OFDM), which extends the principles of OFDM modulation to a 2D domain is proposed. Unlike traditional OFDM scheme, which relies solely on time-frequency processing, 2D-DCT-OFDM exploits an alternate 2D transform domain for information mapping and employs 2D-DCT operations along these dimensions for signal processing. Here, the design principles and performance analysis of the proposed 2D-DCT-OFDM modulation scheme are presented. Finally, the BER performance of the proposed 2D-DCT-OFDM scheme for different user equipment velocities are obtained and compared with the prior 1D and 2D modulation schemes (such as DFT-s-OFDM and OTFS) to get pertinent candidate waveform suggestions for beyond 5^th generation (B5G) and 6G cellular systems. Simulation results show that the 2D modulation schemes provide better BER performance in high-mobility scenarios. In addition, 2D-DCT-OFDM provides slightly better BER performance than other 2D modulation schemes under extreme mobility with significantly less computational complexity. Due to the simplicity, computational efficiency, ease of implementation, and power efficiency of 2D-DCT-OFDM, it is suitable for beyond 5G and 6G.