A Time-Delay Overlapping Modulation Based High Spectral Efficiency Multi-User Differential Chaos Shift Keying for Maritime Internet of Vessels

The scarce maritime spectrum resource prevents the maritime communication network from carrying more users. In this letter, an offshore multi-user differential chaos shift keying scheme based on the time-delay overlapping modulation (TDOM-MUDCSK) is proposed. The TDOM technique can use the bandwidth of a single subcarrier to carry information bits. Thus, the bandwidth occupied by all users can be significantly reduced, indicating that the maritime communication network can accommodate more users based on the saved spectrum resource. The multi-user communication mechanism and system structure for both downlink and uplink communication scenarios are designed, and the spectrum efficiency and complexity are analyzed. In addition, the BER expression under the maritime communication channel is derived, and a method to weaken inter-carrier-interference (ICI) is demonstrated. Simulation results verify the theoretical derivations and show the superiority of the system.