EMS Picture Concatenation

[Chris . Forlano]

I've read over some of this summer's threads and there seemed to be some debate 
over:
*       where an EMS picture message is stored in each SMS message
*       how concatenation is handled for EMS pictures that are larger than the 
size of a single SMS segment

I am wondering if you can clarify.

My understanding of EMS (mind you I am still coming up to speed), is that each 
Information Element Data (i.e., a small, large, or variable size picture) is 
actually stored in the User Data Header of each message (as oppossed to storing 
the picture in the User Data portion of that message).  The GSM/3GPP spec's 
support this with their examples.

When a standard SMS message is greater than the available data in the message 
(160 for 7-bit, 140 for 8-bit, and 70 for 16-bit), the GSM standard for 
concatenation is used to break up the message payload in the User Data into a 
series of SMS segments.  The control information for this concatenation is 
stored in the User Data Header of each SMS segment.  This allows the message 
segments to be reconstructed at the other end in a ringtone, picture, etc.

What is unclear to me is how the GSM standard handles the creation of 
concatenation segments for EMS picture messages.  As the picture itself, lives 
in the User Data Header, it is possible that the picture is actually larger 
than the maximum size of an SMS, thereby, making the header larger than the SMS.

If this is the case, does than mean that the User Data Header "itself" is 
broken up across several message segments?  In this scenario, is there really 
no User Data (as this space is monopolised by the User Data Header)?

I know this is more of a GSM SMS questions, but I am hoping someone can address 
this as it would greatly be appreciated.

Thanks in advance,

Chris

Chris Forlano
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