Doppler Scaling Factor Tracking for OCDM Communications

High mobility and high rate are prerequisites of 6G wireless communications. Orthogonal chirp division multiplexing (OCDM) is recently proposed as a promising modulation scheme for 6G. It offers robustness against burst interference in both time and frequency domains. However, the Doppler scaling factor due to the transceivers’ mobility imposes great challenges. It is nonlinear and time-varying. To address the Doppler issue, this paper proposes a Doppler tracking algorithm for OCDM communications. The algorithm estimates the initial Doppler scaling factor using time-domain correlation of preamble blocks, then refines it using the cyclic prefix (CP) of each OCDM data block within the frame. It estimates the current block’s acceleration, predicts the next block’s velocity, and captures acceleration changes to improve tacking accuracy. Simulation results verify that the proposed algorithm outperforms the state of the art in various scenarios, and demonstrates its practical advantage.