An Improved MAC Protocol Design in VHF Data Exchange System (VDES) For Internet of Vessels

In recent year, the VDES (VHF Data Exchange System) has drawn extensive attention and admiration in the international maritime field and Internet of Vessels. It has been identified as a core data exchange platform for e-Navigation strategy in the future. However, the traditional Self-Organizing Time Division Multiple Access (SOTDMA) protocol of the Automatic Identification System (AIS) has not met the demands of the huge increases in VHF Data Link (VDL) loading. This paper proposes an improved SOTDMA (iSOTDMA) protocol for VDES to reduce the slot reservation collision rate, thereby improving the system performance. Finally, we present experimental results which show that the proposed iSOTDMA protocol can achieve better performance than the original SOTDMA in terms of slot reservation conflict rate.