In this paper, the problem of channel estimation for Superposition Coded Modulation-Orthogonal Frequency Division Multiplexing (SCM-OFDM) systems over frequency selective channels is investigated.

Extremely large-scale multiple-input-multiple-output (XL-MIMO) at millimeter-wave (mmWave) and terahertz (THz) bands plays an important role in 6G networks for its merits of extreme high beamforming ...