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Posts: 8
Registered: ‎04-06-2017
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Si4684 payload data format for DSCTy = MOT and TMC

I have the AN649 Rev 1.8, it does not mention the DLS service data format when the DSCTy is not DLS/DL+. I need to know the format for other DSCTy type, such as TMC and MOT. Is there any updated release for AN649, or any other document telling these?

 

Regards,

Colman

 

Posts: 77
Registered: ‎02-15-2015

Re: Si4684 payload data format for DSCTy = MOT and TMC

Posts: 8
Registered: ‎04-06-2017

Re: Si4684 payload data format for DSCTy = MOT and TMC

I have read them, but I don't know how the PAD data are related to them!

 

Colman

Posts: 77
Registered: ‎02-15-2015

Re: Si4684 payload data format for DSCTy = MOT and TMC


colman wrote:

I have read them, but I don't know how the PAD data are related to them!


Then I'd recommend to read ETSI EN 300 401, chapter 7.4 Programme Associated Data (PAD).

 

Best regards,

Andi

Posts: 8
Registered: ‎04-06-2017

Re: Si4684 payload data format for DSCTy = MOT and TMC

Sorry, I still cannot understand it, below is the first 32 bytes of the payload when DATA_src=1, DSCTy=60 from a response of command 0x84 (GET_SERVICE_DATA). Can you explain how to decode it?

 

 

74 E0 80 0A 12 86 65 01-F1 FC 5B 14 F1 30 22 4B 
38 DB 8E DC B6 3F 4F E7-5D 27 DA 3E 20 5C 42 23

....

 

some begins with 0x73, as

73 70 80 00 12 86 65 00-25 00 01 CC 70 12 84 01
85 00 00 00 00 CC 15 00-52 61 70 69 64 53 4C 53

...

 

Regards,

Colman

 

 

Posts: 77
Registered: ‎02-15-2015

Re: Si4684 payload data format for DSCTy = MOT and TMC


colman wrote:

Sorry, I still cannot understand it, below is the first 32 bytes of the payload when DATA_src=1, DSCTy=60 from a response of command 0x84 (GET_SERVICE_DATA).


DSCTy=60 means it's MOT.

The data begins with headers as defined in EN 300 401, 5.3.3 Packet mode - data group level 

 

Headers.png

 

So let's decode your first expample data:

 

74 E0 80 0A 12 86 65 01 F1 FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23

MSC data group header = 74 E0
 01110100 ‭11100000‬
  Extension flag = 0
  CRC Flag = 1
  Segment flag = 1
  User access flag = 1
  Data group type = 0x4 -> MOT body
  Continuity index = 0xE
  Repetition index = 0x0

Session header = 80 0A 12 86 65
 Segment field = 80 0A
  ‭ 10000000 00001010‬
    Last = 1
    Segment number = 0xA (10)
 User access field = 12 86 65
  ‭00010010‬
   Rfa = 0x0
   Transport Id flag = 1
   Length indicator = 0x2
   Transport Id = 0x8665

MSC data group data field = 01 F1 FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23 ...

-> This (MSC data group data field) now is the MOT data (to be fed to MOT decoder), composed of headers and data according to EN 301 234

 

First part is according to 5.1.1 Segmentation header

Mot_segHeader.png

 Segmentation header = 01 F1
   ‭00000001 11110001‬
    Repetition count = 0x0
    Segment size = 0xF1 (241)

 

Then follows Segment data = FC 5B 14 F1 30 22 4B 38 DB 8E DC B6 3F 4F E7 5D 27 DA 3E 20 5C 42 23 ...

 

Best regards,

Andi

Highlighted
Posts: 8
Registered: ‎04-06-2017

Re: Si4684 payload data format for DSCTy = MOT and TMC

I am clear now. Thank you very much!

 

Colman