Jiang, Y.; Zheng, Y.; Wang, J. A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE). J. Mar. Sci. Eng.2020, 8, 83.
Jiang, Y.; Zheng, Y.; Wang, J. A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE). J. Mar. Sci. Eng. 2020, 8, 83.
Jiang, Y.; Zheng, Y.; Wang, J. A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE). J. Mar. Sci. Eng.2020, 8, 83.
Jiang, Y.; Zheng, Y.; Wang, J. A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE). J. Mar. Sci. Eng. 2020, 8, 83.
Abstract
VHF Data Exchange System (VDES) is considered as an important component of the future maritime communication system by the International Maritime Organization (IMO). On the basis of existing Automatic Identification System (AIS), VDES adds the other two higher capacity subsystems: Application Specific Message (ASM) and VHF Data Exchange (VDE). The Random Access Channel (RACH) of VDE was first introduced in the International Telecommunication Union (ITU) Recommendation M.2092-0. As the slot planning of RACH in VDE is interval, which is significantly different from the continuous slot map for access algorithms in AIS, the existing slot access algorithms cannot meet the requirements of VDE. The simulation results show that the VDE slot map can reduce the normalized throughput of the existing algorithm by 39%. A novel random access algorithm called Adaptive Traffic Load Contention Resolution Diversity Slotted ALOHA (ATL-CRDSA) is proposed in this paper. The algorithm combines the load control strategy and contention resolution scheme to overcome the challenges of the new RACH of VDE. Simulation results show that ATL-CRDSA has remarkable improvement on RACH, and makes RACH very efficient and provides low latency of the packets. The insights gained from this study may be of assistance to the Media Access Control (MAC) layer design for upcoming versions of VDES standard.
Keywords
VDES; VDE; ATL-CRDSA; Load control; RACH
Subject
Engineering, Marine Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
