A Novel Embedded Pilot-Aided OCDM System Over Time-Varying Channels

In this letter, we propose a novel embedded pilot orthogonal chirp division multiplexing (OCDM) system. This system is mainly used for time-varying (TV) channels to reduce the overhead of OCDM channel estimation. In this system, a novel embedded chirp pilot arrangement in the discrete Fresnel domain with low overhead is designed. Furthermore, two channel estimation strategies are proposed for this pilot arrangement: a low-complexity data interference avoidance (IA) strategy and a higher-performance data interference suppression (IS) strategy. For the IS strategy, we also develop a novel channel estimator. Through simulation and analysis, we have demonstrated that the proposed system effectively improves the spectrum efficiency, energy efficiency, and transmission rate (SET) compared to traditional embedded pilot OCDM systems, while maintaining similar performance levels.