Why AIS isn’t Enough AIS has proved itself to be an integral part of maritime communications and therefore we can expect ever increasing regional uses, many of which cause severe VDL loading e-Navigation must have a very cost effective communication path to be widely used and accepted – an extension of AIS is a natural, and very cost effective solution

What to do … Clean up the AIS channels – Move the ASM’s for safety related, navigation related and efficiency related information to two new very robust ASM channels Provide Greater Capacity – Define the VDE with wider channelization and more efficient modulation techniques to push through more bits in the same time frame; The VDE channels must handle more data but are not required to be as robust as the ASM channels. – The VDE channels will support specialized regional environments by using adaptive modulation schemes and forward error correction. This allows maximizing the throughput of the data channels while considering the behavior of the channel.

VDES Step 1 ITU WRC-15 convened in November of 2015 and approved the following: – Two 25kHz channels, ASM1 and ASM2, to support Application Specific Messages; ASM1 and ASM2 will support satellite-up applications; – Two banks of 100kHz channels, used between ship-ship, ship-shore and shore-ship; Countries are asked to respect this new usage by 2019

What’s Different? Much more robust link including: – Longer training sequence – Longer CRC – Interleaving – Bit Scrambling – Forward Error Correction – More efficient modulation techniques – Cybersecurity considerations

ASM Channels Baseline modulation (method allows for future modulations) will be π/4 Quadrature Phase-Shift Keying (QPSK); 28 symbol training sequence and 32 bit CRC; Forward Error Correction allowed as needed; Bit Scrambling (if no FEC); RATDMA and ITDMA (FATDMA) for all messages; CSTDMA for 1 slot messages (satellite) Modified Packet bit structure for ASM messages intended for satellite reception;

VDE-TER VDE for Terrestrial Harmonize the ASM and VDE where practical (training sequence, baseline modulation, etc.); The two 100kHz bands may be logically or physically channelized according to the needs for the shore authority, i.e. 25kHz, 50kHz, 100kHz; The channel definition is controlled using a Bulletin Board concept where the shore station is always broadcasting the regional channel allocations;

VDES Step 2 ITU has added an agenda item for WRC-19 requesting information to allow a satellite comms link on the VDES channels. This would be both up and down. IALA is working towards including satellite up and down channels to support the VDES at WRC-19; This work will include field trials to demonstrate non-interference.

What’s Different Fully implemented VDES system must include satellite up/down. The fully implemented VDES system will provide a truly standard comms link capable of providing world-wide coverage; Inclusion of satellite will not require architectural changes because: – All links (Satellite and Terrestrial) managed through the use of Bulletin Board concepts; – Continue to use the same FEC, Interleaving and Bit Scrambling techniques to ensure a robust link between satellite and ship;

Why do we need a Fully Implemented VDES?

Polar Communications

Health and Maintenance Monitoring

True world-wide weather

World-wide VTS

GMDSS Modernization