Delay–Doppler Block Division Multiplexing: An Integrated Navigation and Communication Waveform for LEO PNT

The recent rapid deployment of low-Earth-orbit (LEO) broadband constellations has positioned these systems as expected emerging navigation sources, thereby driving research interest in integrated navigation and communication (INAC) technologies. Existing INAC waveforms face various challenges in LEO environments, including limited ranging accuracy due to high mutual interference (MI) between signal components, a heavy signal processing burden for navigation users, or degraded data transmission reliability. We propose an INAC waveform named delay–Doppler block division multiplexing (DDBDM) in this work. MI is effectively reduced by modulating pseudo-random noise (PRN) codes and data separately on orthogonal delay–Doppler (DD) blocks. Navigation and communication signals in DDBDM can be separated in the frequency band, which allows the user to receive only the bandwidth occupied by the navigation subcarriers, reducing the signal processing overhead. Moreover, data transmission in the DD domain exhibits a low bit error rate in high-mobility channels, which enables fast and reliable navigation augmentation information for users. Simulation results demonstrate that DDBDM offers superior navigation performance and data transmission reliability compared to existing INAC schemes. The proposed waveform enhances the performance of the LEO INAC system and effectively extends the position, navigation, and timing (PNT) service capability.