In the paper, the measurement and simulation results of the VDES (vhf data exchange system) terrestrial component are discussed. It is anticipated that VDES will be one of the major solutions for maritime communicatio...
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In the paper, the measurement and simulation results of the VDES (vhf data exchange system) terrestrial component are discussed. It is anticipated that VDES will be one of the major solutions for maritime communications in the vhf band and its performance will be sufficient to fulfill the requirements of the e-navigation applications. The process of the VDES standardization (ITU R, IALA) has not been officially completed yet, but substantial amount of technical information about the future system's terrestrial component (VDE-TER) is already available. The paper is divided into three general parts: (a) theoretical presentation of the system's physical layer and the radio channels applicable to VDES, (b) simulation results (BER, BLER, channel delay between two propagation paths and its influence on bit rates) and (c) measurement results (useful ranges, BER). It turned out that in real maritime conditions, the VDES system can offer ranges between 25 and 38 km for the configurations assumed during the measurement campaign. Those results are generally compliant with the theoretical data in the line-of-sight conditions. In the NLOS scenarios, where fading becomes the dominant phenomenon, the discrepancies between the measurements and the theoretical results were more significant. The obtained results confirmed that VDES provides a large coding gain, which significantly improves the performance of data transmission and increases the bit rate compared to the existing maritime radiocommunication solutions. It should be noted that the results presented in the article were used by the IALA while developing the current version of the VDES specification.
With the vigorous development of the navigation industry, the VDES(vhf data exchange system) has received extensive attention from various research institutions. In order to solve the multipath fading problem in vhf w...
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ISBN:
(纸本)9781728129808
With the vigorous development of the navigation industry, the VDES(vhf data exchange system) has received extensive attention from various research institutions. In order to solve the multipath fading problem in vhf wireless channel transmission, this paper integrates FMT (Filtered Multitone Modulation) technology into VDES ground subsystem, redesigns the system time slot structure under the protocol framework, constructs the underlying communication link of VDES ground subsystem based on FMT. Simulation results show that the performance of the system using FMT technology is slightly better than that using OFDM technology, and the spectrum utilization and frequency offset resistance are improved. Research demonstrates that the introduction of FMT into VDES can effectively solve the multipath interference problem and has certain value for the practical application of VDES.
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