1. Mobile Communication

2. Transaction/Submit, deliver, report and command SMS-Submit: This transaction corresponds to the submission of the message from SME to SMSC. The SMSC acknowledges the submission with SMS-SUBMIT-REPORT SMS-Deliver This transaction corresponds to the delivery of the message from SMSC to SME. The SMSC acknowledges the submission with SMS-DELIVER-REPORT SMS-Status Report This transaction corresponds to the transfer of a status report from an SMSC back to the SME SMS-Command This transaction corresponds to the request from a SME usually an ESME for a specific command At the transfer layer SIX types of transactions can occur between a SME and the SMSC

3. Mobile Communication Transport Protocol Data Unit A TPDU has been assigned to each transaction that can occur between a SME and an SMSC at the transfer layer. High-level parameters in TPDU are bold, TP-MTP, TP-UDHI and TP-UD TP-UDHI – Provides instructions with the presence of binary elements TP-UD – Important parameter which contains the text part of a message segment and may also contain binary elements, instructions, melodies or pictures. The parameter is divided into two sub-parts – UDH: Which contains binary elements while the remaining contains text.

4. Mobile Communication Transport Protocol Data Unit A TPDU has been assigned to each transaction that can occur between a SME and an SMSC at the transfer layer. High-level parameters in TPDU are bold, TP-MTP, TP-UDHI and TP-UD TP-UD – The UDH then is further divided into Sub-Parts, the first sub-part UDHL indicates the length of the UDH in octets. A set of information elements follow. Whatever the coding the UDH is always 8bit encoded. If the UDH is 7bit aligned then fill in bits inserted between UDH and remaining part of TP-UD. This allows older handsets that do not support UDH to use 7bit text

5. Mobile Communication Message Types The set of possible transaction types in fig 3.9 can occur SMSC and the originator or receiving SME. A dedicated value assigned to the TP-MTI corresponds to each transaction type. Fig 3.9

6. Mobile Communication Text Coding Schemes The Two coding schemes used in SMS are GSM 7 bit default alphabet defined in [3GPP-23.038] and the Universal Character Set (UCS2) defined in [ISO-10646] The amount of text that can be included in a message needs to fit in 140 Octets. Fig 3.9 -GSM 7bit DA: is composed of 128 charactors + 9 additional - UCS2:is used for encoding complex sets of non-latin charators such as Arabic/Chinese

7. Mobile Communication Message Classes There are four classes in TP-DCS (data coding scheme) of TPDU which indicate which class the message belongs too. It has to be noted that most cases, a msg does not belong to any of the four classes, therefore a non-class msg is handled as Class 1 or 2 by the receiving SME

8. Mobile Communication Coding Groups A message may belong to one of the three groups. The coding group indicates what the receiving SME should do with the message once it has read or interpreted. The TP-DCS, indicates the coding group to which the message belongs

9. Mobile Communication A message is also associated to a protocol identifier. The protocol Identifier indicates how the receiving message application should handle an incoming message. Protocol Identifier