Channel Estimation for OCDM Transmissions With Carrier Frequency Offset

Abstract

Orthogonal chirp division multiplexing (OCDM) has recently become an appealing scheme for high-speed communications. However, due to the spreading feature of OCDM systems in both time and frequency domains, the channel estimation for OCDM systems with carrier frequency offset (CFO) is challenging. In this letter, we deal with a cyclic-prefix (CP) OCDM system. The CFO is first compensated by making use of the CP. Sequentially, a channel estimator based on superimposed pilot subchirps is proposed. The optimality of the pilot design in minimizing the mean squared error of the channel estimation is proved. The proposed approach is compared with the state-of-the-art and demonstrates superior performance.