VHF Digital Short Message Service or VDSMS

VHF Marine Band radios, protocol, radio communication theory, practical advice; AIS; DSC; MMSI; EPIRB.
jimh
Posts: 11673
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

VHF Digital Short Message Service or VDSMS

Postby jimh » Wed Apr 26, 2017 7:35 am

Recent changes to the Maritime Radio Service (Part 80) by the FCC for incorporation of a VHF DIgital Short Message Service (VDSMS) were described in a notice in the Federal Register on December 15, 2016. Below are some excerpts from that notice:

--begin excerpts--

SUMMARY:
In this document, the Federal Communications Commission (Commission or FCC) addresses a number of important problems regarding updating rules and requirements for technologies used to locate and rescue distressed ships and individuals in distress at sea or on land to provide better and more accurate data to rescue personnel. The Commission also addresses problems regarding radar equipment, the use of portable marine Very High Frequency (VHF) transmitters by persons on shore; permitting VHF digital small message service (VDSMS); and allowing assignment or transfer of control of ship station licenses. The Commission is amending its rules to permit the maritime community to make use of the most advanced and reliable communications technologies available for the alerting of search and rescue authorities when a vessel or individual is in distress, and to further the Commission's goal of ensuring that the spectrum allocated for emergency communications is used effectively and efficiently.

VHF Digital Small Message Services (VDSMS)

28. VDSMS is intended to provide short-distance digital messaging ship-to-ship, shore-to-ship and ship-to-shore. The International Telecommunication Union (ITU) has recognized the future need for worldwide systems to exchange data and email on maritime VHF channels and the availability of new digital data systems that provide this service efficiently and without harmful interference. In the United States, however, maritime communications generally are limited to particular emission designators in order to avoid interference between users; a full range of data transmissions is permitted only on VHF Public Coast frequencies and one channel in Alaska.

29. RTCM developed a technical standard for VDSMS that enables transmission of short digital messages without interfering with other communications on the same channel. The Commission proposed to amend part 80 to incorporate by reference the RTCM VDSMS standard in order to permit transmission of short data messages on VHF maritime private communications frequencies. It tentatively concluded that accommodating VDSMS in the Commission's rules would advance the Commission's goal of promoting flexibility and efficiency in the use of marine radio equipment in a manner that would further maritime safety.

30. RTCM, the only commenter addressing this concern, agrees that part 80 should be revised to incorporate by reference its VDSMS standard. It argues that adopting a single VDSMS standard will avoid use of a variety of different and potentially incompatible data protocols, and ensure VDSMS communications are not disrupted. We agree, and amend part 80 to incorporate by reference the RTCM VDSMS standard. We note that VDSMS will not be permitted on or adjacent to marine safety and security channels and other channels excluded under Appendix 18 of the ITU Radio Regulations.[12] Further, VDSMS operation on the non-excluded VHF frequencies is subject to existing eligibility requirements.

Final Rules

For the reasons discussed in the preamble, the Federal Communications Commission amends 47 CFR parts 1, 25, 80 and 95, as follows:

PART 80—STATIONS IN THE MARITIME SERVICES

§ 80.7 Incorporation by reference.

(4) RTCM Standard 12301.1 (“RTCM 12301”), “VHF-FM Digital Small Message Services,” July 10, 2009, IBR approved for § 80.364(a).

jimh
Posts: 11673
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: VHF Digital Short Message Service or VDSMS

Postby jimh » Wed Apr 26, 2017 7:52 am

Another FCC document mentions more about VDSMS and the RTCM standard. This information is reproduced below:

--begin excerpts----

29. RTCM developed a technical standard for VDSMS that enables transmission of short digital messages without interfering with other communications on the same channel.[See note 92 below.]

In the Notice, the Commission proposed to amend Part 80 to incorporate by reference the RTCM VDSMS standard in order to permit transmission of short data messages on VHF maritime private communications frequencies. [See note 93 below]

It tentatively concluded that accommodating VDSMS in the Commission’s rules would advance the Commission’s goal of promoting flexibility and efficiency in the use of marine radio equipment in a manner that would further maritime safety.[See note 94 below]

30. RTCM, the only commenter addressing this concern, agrees that Part 80 should be revised to incorporate by reference its VDSMS standard. [See note 95 below] It argues that adopting a single VDSMS standard will avoid use of a variety of different and potentially incompatible data protocols, and ensure VDSMS communications are not disrupted.[See note 96 below]

We agree, and amend Part 80 to incorporate by reference the RTCM VDSMS standard. We note that VDSMS will not be permitted on or adjacent to marine safety and security channels and other channels excluded under Appendix 18 of the ITU Radio Regulations. [See note 97 below]

Further, VDSMS operation on the non-excluded VHF frequencies is subject to existing eligibility requirements. [See note 98 below]

Notes:

92. RTCM Standard 12301.1 for VHF-FM Digital Small Message Services, dated July 10, 2009. The standard contains general requirements for VDSMS, e.g., operating frequencies, channel access method, receiver characteristics, and electromagnetic compatibility with other radio systems in the geographical/spectral vicinity of the VDSMS. See id. at 1. It allows for VDSMS to be integral to marine VHF receiving and transmitting communications equipment, and specifies a channel access method that transmits data only when the channel is not being used, so that calls in progress are not disrupted.

93. See Notice, 29 FCC Rcd at 2530-31 ¶ 36. Channels in the 156-162 MHz band in the international VHF Marine Band are made available according to the type of communication and the nature of the ship’s operation. Private communications frequencies are available for safety communications, calling, control of ship movement, and navigational purposes. See 47 C.F.R. § 80.373(f).

94. See Notice, 29 FCC Rcd at 2530 ¶ 36.

95. See RTCM Comments at 8.

96. Id. at 8-9

97. As suggested by NTIA, we include port operations channels among the marine safety channels on which VDSMS
will not be permitted. Port operations communications are “[c]ommunications in or near a port, in locks or in
waterways between coast stations and ship stations or between ship stations, which relate to the operational
handling, movement and safety of ships and in emergency to the safety of persons.” 47 C.F.R. § 80.5.

98. See 47 C.F.R. § 80.373(f).