Improving Doppler Resilience of OFDM through Delay-Doppler Sensing

2026-06-19

AI Summary

This work addresses the severe performance degradation of CP-OFDM under doubly dispersive channels caused by inter-carrier interference (ICI). To mitigate this issue, the paper introduces delay-Doppler (DD) domain awareness into CP-OFDM systems for the first time, overlaying Zadoff-Chu pilots onto data subcarriers and constructing an accurate frequency-domain input–output relationship based on DD-domain channel estimation. Leveraging this model, the proposed method jointly performs pilot cancellation and data detection, effectively suppressing ICI. By circumventing the limitations of conventional time–frequency processing—which struggles to accurately characterize the frequency-domain input–output relation—the approach significantly enhances Doppler resilience and spectral efficiency in high-mobility scenarios, as demonstrated under the 3GPP TDL-C channel model.

Abstract

The performance of traditional CP-OFDM degrades severely in doubly-spread wireless channels due to inter-carrier interference (ICI). In this paper, we propose DD domain sensing based CP-OFDM where we transmit a Zadoff-Chu (ZC) pilot signal overlaid on CP-OFDM data carriers. At the receiver, DD domain signal processing is used to acquire the effective DD domain channel filter which is stationary in the DD domain. From this DD domain estimate, we derive the complete frequency domain (FD) input-output (I/O) relation between CP-OFDM carriers, acquiring which is otherwise difficult with traditional time-frequency signal processing. Using this FD I/O relation, we estimate the received FD pilot signal which is then canceled from the received FD signal, resulting in a data-only signal. Joint detection of all CP-OFDM data carriers from this data-only signal equalizes the effect of ICI. Numerical simulations of the standardized 3GPP TDL-C channel shows that in high mobility scenarios, the proposed DD domain sensing based CP-OFDM achieves significantly better spectral efficiency when compared to that achieved by traditional CP-OFDM.

Problem

• Doppler resilience
• OFDM
• inter-carrier interference
• doubly-spread channels
• CP-OFDM

Innovation

• Delay-Doppler sensing
• CP-OFDM
• inter-carrier interference (ICI)
• Zadoff-Chu pilot
• Doppler resilience