ETSI DENM Message

[iTacco]

Hello everybody,
I have a question about the etsi denm messsage send by the "V2xMessageTransmission" interaction inside the Barnim scenario.

This is how the whole V2xMessageTransmission interaction looks like in json:
{"V2xMessageTransmission":{"message":{"payload":{"contentClassName":"org.eclipse.mosaic.lib.objects.v2x.etsi.DenmContent","bytes":[0,0,0,-25,-26,57,-24,0,64,74,83,60,12,31,-56,-13,64,43,23,10,61,112,-93,-41,0,0,0,0,0,0,0,0,1,0,27,45,51,51,54,54,95,50,48,50,54,51,54,50,57,52,48,95,49,51,49,51,56,56,53,53,48,50,1,0,64,-34,56,-28,0,0,0,0,1,64,74,81,7,-81,32,-22,91,64,43,33,112,-42,43,-15,32,0,0,0,0,0,0,0,0,0,0,0,0,0],"lengthInBytes":102,"minimalLength":200},"denmContent":{"time":996000000000,"senderPosition":{"latitude":52.65027,"longitude":13.545},"eventRoadId":"-3366_2026362940_1313885502","warningType":"ICE","eventStrength":0,"causedSpeed":6.9444447,"senderDeceleration":0.0,"eventLocation":{"latitude":52.633047,"longitude":13.565314}},"routing":{"source":{"sourceAddress":{"address":"10.2.0.0"},"sourceName":"rsu_0","sourcePosition":{"latitude":52.65027,"longitude":13.545}},"destination":{"destinationAddress":{"address":"255.255.255.255"},"type":"CELL_GEOCAST","disseminationArea":{"center":{"latitude":52.633047,"longitude":13.565314},"radius":3000.0},"protocolType":"UDP"}},"id":3141,"sequenceNumber":499},"time":996000000000,"id":52172,"senderId":"application","typeId":"V2xMessageTransmission"}}

But I am interested in the "bytes" array: "bytes":[0,0,0,-25,-26,57,-24,0,64,74,83,60,12,31,-56,-13,64,43,23,10,61,112,-93,-41,0,0,0,0,0,0,0,0,1,0,27,45,51,51,54,54,95,50,48,50,54,51,54,50,57,52,48,95,49,51,49,51,56,56,53,53,48,50,1,0,64,-34,56,-28,0,0,0,0,1,64,74,81,7,-81,32,-22,91,64,43,33,112,-42,43,-15,32,0,0,0,0,0,0,0,0,0,0,0,0,0].

As I am expecting this byte array should represent a DENM byte message in the "ETSI DENM EN 302 637-3 v1.3.1" format.
The array is a list of signed integers which cannot be decoded by following online decoder: https://www.marben-products.com/decoder-asn1-automotive/
So I transformed the array in something similar to this:
`Decimal stream:

0, 0, 0, -24, 93, 111, 124, 0, 64, 74, 83, 60, 12, 31, -56, -13, 64, 43, 23, 10, 61, 112, -93, -41, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 27, 45, 51, 51, 54, 54, 95, 50, 48, 50, 54, 51, 54, 50, 57, 52, 48, 95, 49, 51, 49, 51, 56, 56, 53, 53, 48, 50, 1, 0, 64, -34, 56, -28, 0, 0, 0, 0, 1, 64, 74, 81, 7, -81, 32, -22, 91, 64, 43, 33, 112, -42, 43, -15, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

to this hex stream:
00 00 00 e8 5d 6f 7c 00 40 4a 53 3c 0c 1f c8 f3 40 2b 17 0a 3d 70 a3 29 00 00 00 00 00 00 00 00 01 00 1b 2d 33 33 36 36 5f 32 30 32 36 33 36 32 39 34 30 5f 31 33 31 33 38 38 35 35 30 32 01 00 40 de 38 e4 00 00 00 00 01 40 4a 51 07 af 20 ea 5b 40 2b 21 70 d6 2b f1 20 00 00 00 00 00 00 00 00 00 00 00 00 00`

and put it into the online decoder shown above. But the output isn't a valid DENM message.

So I am asking myself if I had done something wrong or this isn't a valid ETSI DENM message at all or I have to handle the byte array in a different way.

Thanks in advance,
iTacco

[rprotzmann]

Regarding the modelling of ETSI standardized V2X messages like DENM and CAM, we focused primarily on the content.

Our main goals are:

• Incorporation of most important fields and containers of the messages
• Flexibility to include additional content, which is not standardized up to now (extendedContainers for DENM, userTaggedValue for CAM)
• Support of advanced sending schemes with (periodic) retransmissions
• Performance for simulation of many vehicles / nodes and messages

Due to the last goal, we currently do NOT employ ASN.1 formatting in the provided message handling.

Moreover, we usually cache the message payload in the Application Simulator and in the V2xMessageTransmission only hand over Meta information for the message like Id, Routing, Timestamp and Length, which are needed for Communication Simulation. On reception, the Application Simulator fetches the payload from its cache and distributes it to the receiving entities.

The EncodedPayload allows for publishing of the payload as serialized Java object in the V2xMessageTransmission, if needed in a simulator or logger. Yet, it is not ASN.1 formatted.