AI 1.9.2 Maritime VDES

Background

Studies associated with WRC-15 agenda item 1.16 resulted in the development of a concept for the VDES which is reflected in Recommendation ITU-R M.2092-0. This Recommendation was developed in the WRC-15 study cycle. The system combines the current automatic identification system (AIS), applications specific messages (ASM) as well as VHF data exchange (VDE), which has a terrestrial component (VDE-TER) and a satellite component (VDE‑SAT).

WRC-15 allocated frequencies for the terrestrial component of VDES, including ASM satellite uplink. However the WRC15  requested further compatibility and sharing studies between VDE-SAT and other services in the same and in the adjacent frequency bands.

The results of sharing and compatibility studies are contained in Recommendation ITU-R M.2092-0 and Report ITU-R M.2435-0, which has been developed in this study cycle.

Based on the results of these studies, six methods have been developed to satisfy WRC-19 agenda item 1.9.2. The main differences between the methods are the frequency plan and power flux density mask (pfd-mask) to be imposed on the MMSS (space-to-Earth) emissions, which are further described in Report ITU-R M.2435-0.

Method A

No change to the Radio Regulations except suppression of Resolution 360 (Rev.WRC-15). As a result there will be no frequency allocations to the satellite component of VDES (VDE-SAT).

Method B

This method proposes new primary allocations to the maritime mobile-satellite service (MMSS) (Earth-to-space) and (space-to-Earth) using a particular frequency plan approach. The coordination mechanism with respect to terrestrial services under RR No. 9.14 is introduced with two options for the pfd-mask.

Method C

This method uses the same frequency plan as Method B but with new secondary allocations for the MMSS (Earth‑to-space) and (space-to-Earth).

Due to the proposed secondary status of the allocation to the MMSS, there is no coordination required between the MMSS and terrestrial services and therefore there is no need to make any modifications to Appendix 5 of the RR.

Method D

This method is the same as Method C except with the addition of a pfd limit in RR Article 5 in order to protect the terrestrial services. This method includes two options including the description of the pfd masks.

Method E

This method proposes new secondary allocations for the MMSS (Earth‑to-space) and (space-to-Earth) subject to agreement in accordance with No. 9.21 of the RR to be limited to the use of the VDES satellite component to ensure compatibility with existing services.

Method F

This method proposes new primary allocations to the MMSS (Earth-to-space) and (space-to-Earth) using a different frequency plan approach. Details on the pfd mask for coordination of MMSS (space-to-Earth) with respect to terrestrial services were developed.

 

CEPT proposals

CEPT proposes the changes to the Radio Regulations in order to introduce the VHF data exchange system (VDES) satellite component (VDE-SAT) to support the digital evolution of maritime communications.

CEPT proposes a new primary allocation to the maritime mobile-satellite service (MMSS) (Earth-to-space) in the certain frequency bands near 157 and 161 MHz. These two frequency bands correspond to channels 24, 84, 25, 85, 26 and 86 of Appendix 18. Within the context of VDES, channels 26 and 86 are identified for ship-to-satellite (VDE-SAT uplink) communications. The channels 24, 84, 25 and 85 are identified for the VDES terrestrial component (VDE-TER), but ship-to-satellite (VDE-SAT uplink) communications are possible without imposing constraints on VDE-TER.

CEPT also proposes a new primary allocation to the maritime mobile-satellite service (space-to-Earth) in the frequency band 160.9625‑161.4875 MHz, which is identified for satellite-to-ship (VDE-SAT downlink) communications. CEPT propose that coordination of MMSS (space-to-Earth) emissions in that frequency band with respect to terrestrial services will be captured under RR No 9.14. This is introduced by a new footnote.

CEPT propose modifications to footnotes and Annex 1 to Resolution 739 (Rev.WRC-15) in order to ensure protection of the radio astronomy service (RAS) in the frequency bands 150.05-153 MHz and 322-328.6 MHz.

This proposal is supported by the studies provided in Report ITU-R M.2435-0, and corresponds to Method B with one of the pfd mask options.