Presentation On Sms Working

SMS Short Message Service

What is SMS? SMS stands for short message service. SMS is also often referred to as texting, sending text messages or text messaging. The service allows for short text messages to be sent from one cell phone to another cell phone or from the Web to another cell phone. Including spaces, text messages traditionally can’t exceed 160 characters.

History of SMS • Appeared on the wireless world in 1991 in Europe. • In North America, SMS was made available initially on digital wireless networks built by early pioneers such as BellSouth Mobility, PrimeCo and Nextel, among others. • There was hardly any promotion as few people predicted that this service would take off.

History Contd.. • Fortunately, SMS was a success and it took everyone in the mobile industry by surprise. • First short message – sent in December 1992 from a personal computer to a mobile phone on the Vodafone GSM (Global System for Mobile Communications) Network in the UK. • In April 1999, SMS market in the European Union reached one billion short messages per month.

History Contd.. • It had become one of the few services in consumer history that has grown very fast without corresponding decrease in pricing. • However, after SMS charging came about – a decline in usage of about 25% to 40%

SMS Length • A single short message can be up to 160 characters of text in length using default GSM alphabet coding • 140 characters when Cyrillic character set is used • 70 characters when UCS2 international character coding is used

TT4113-SisKomSel-extMODUL:09b

TT4113-SisKomSel-extMODUL:09b

UCS-2 UCS-2 (2-byte Universal Character Set) • The UCS-2 encoding form is identical to that of UTF16(16-bit UCS/Unicode Transformation Format), except that it does not support surrogate pairs and therefore can only encode characters in the BMP range U+0000 through U+FFFF. • A pair of 16-bit words, together called a surrogate pair • As a consequence it is a fixed-length encoding that always encodes characters into a single 16-bit value. TT4113-SisKomSel-extMODUL:09b

GSM alphabet coding

Cyrillic Character set

Channel Assignment • SDCCH (Stand Alone Control Channel) when not on a call • SACCH (Slow associated control channel) When we are on a call

TT4113-SisKomSel-extMODUL:09b

How SMS works • Once message is sent, it is received by a Short Message Service Center (SMSC), which then gets it to the appropriate mobile device. • SMSC sends a SMS Request to the home location register (HLR) to find the roaming customer.

Contd.. • On reception, HLR responds to the SMSC with the subscriber’s status I.e. active or inactive. • Inactive – SMSC holds message for a period of time. • Active – HLR sends a SMS notification to the SMSC attempts delivery.

Contd.. • SMSC transfers message in a Short Message Delivery Point to Point format to the serving system – if system responds, message gets delivered. • SMSC receives verification that message was received by the end user.

MO SMS Transfer MS 1 CHANNEL REQUEST DCCH ASSIGN

BSS

MSC



SIGNALING LINK ESTABLISHED

TT4113-SisKomSel-extMODUL:09b

VLR

Interworking MSC

SC

MO SMS Transfer MS 1 CHANNEL REQUEST DCCH ASSIGN

BSS

MSC



SIGNALING LINK ESTABLISHED 2 REQ. FOR SERVICE

<SDCCH>

CR CC

TT4113-SisKomSel-extMODUL:09b

VLR

Interworking MSC

SC

MO SMS Transfer MS 1 CHANNEL REQUEST DCCH ASSIGN

BSS

MSC



SIGNALING LINK ESTABLISHED 2 REQ. FOR SERVICE

<SDCCH>

CR CC

3 AUTHENTICATION SET Cipher MODE

TT4113-SisKomSel-extMODUL:09b

VLR

Interworking MSC

SC

MO SMS Transfer MS 1 CHANNEL REQUEST DCCH ASSIGN

BSS

MSC



SIGNALING LINK ESTABLISHED 2 REQ. FOR SERVICE

<SDCCH>

CR CC

3 AUTHENTICATION SET Cipher MODE 4 RP_MO_DATA SIF_MO_SMS SIF_MO_SMS-Ack

TT4113-SisKomSel-extMODUL:09b

VLRInterworking MSC

SC

MO SMS Transfer MS 5 MO_Forward_SM

BSS

MSC

VLRInterworking

(SC_No.)

Short_Message Short_Message_Ack MO_Forward_SM_Ack

TT4113-SisKomSel-extMODUL:09b

MSC

SC

MO SMS Transfer

MS

BSS

MSC

VLR

(SC_No.)

5 MO_Forward_SM Short_Message Short_Message_Ack MO_Forward_SM_Ack

6 RP_ACK "Send Successfully" is displayed on the mobile

TT4113-SisKomSel-extMODUL:09b

Interworking MSC

SC

MT SMS Transfer

For Forwarding a Short Message

For Forwarding Several Short Message

TT4113-SisKomSel-extMODUL:09b

MT SMS Transfer (A Message) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (A Message) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM 2 SIF_MT_SMS Page Page

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (A Message) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM 2 SIF_MT_SMS Page Page 3 Paging Response Authentication and Ciphering

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (A Message) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM 2 SIF_MT_SMS Page Page Request 3 Paging Response Authentication and Ciphering 4 Short_Message Short_Message_Ack MT_Forward_SM_Ack Short_Message_Ack

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (Several Messages) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM MT_Forward_SM (The More message To Send Flag is True)

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (Several Messages) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM MT_Forward_SM (The More message To Send Flag is True) 2 SIF_MT_SMS Page Paging Request

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (Several Messages) MS

Servicing MSC

VLR

1 Short Message SRI_For_SM SRI_For_SM_Ack MT_Forward_SM MT_Forward_SM (The More message To Send Flag is True) 2 SIF_MT_SMS Page Paging Request

3 Paging Response Authentication and Ciphering

TT4113-SisKomSel-extMODUL:09b

HLR

Gateway MSC

SC

MT SMS Transfer (Several Messages) MS

Servicing MSC

VLR

HLR

4 Short_Message Short_Message_Ack MT_Forward_SM_Ack Short_Message_Ack

TT4113-SisKomSel-extMODUL:09b

Gateway MSC

SC

MT SMS Transfer (Several Messages) MS

Servicing MSC

VLR

HLR

4 Short_Message Short_Message_Ack MT_Forward_SM_Ack Short_Message_Ack 5 Short_Message MT_Forward_SM MT_Forward_SM (The More message To Send Flag is False) Short_Message Short_Message_Ack MT_Forward_SM_Ack Short_Message_Ack

TT4113-SisKomSel-extMODUL:09b

Gateway MSC

SC

Answer

MS

BSS

MSC

VLR

(SC_No.)

MO_Forward_SM Short_Message Short_Message_Ack Illegal Subscriber

MO_Forward_SM_Ack Illegal Subscriber

RP_ACK "Send Not Successfully" is displayed on the mobile

TT4113-SisKomSel-extMODUL:09b

Interworking MSC

SC

SMS summary • SMS is much more than just some text. • Sophisticated features are bound to open up holes (virus). • SMS very suited to bulk application (like e-mail) • Trustworthiness as bad or worse as with standard e-mail. TT4113-SisKomSel-extMODUL:09b

Applications

Consumer • Simple person to person paging – usually to say hello, arrange a meeting etc. • Voice and fax mail notifications – notification of new messages waiting. • Unified messaging – messages can be conveniently accessed from a single point.

Application Contd.. • Internet mail alerts • Information services – in some areas, wide range of information including share prices, weather flight information, news headlines etc.

Advantages of SMS

Advantages • An ideal messaging system – for short messages or when it would take too long to have a full conversation or even for someone traveling overseas and not able to take a voice call. • Direct notification of new messages – no dial up for periodical checks to mailbox.

Advantages Contd.. • Messages can be still be received during a call. • Eliminates need for separate devices for messaging since services can be integrated into a single wireless device. • Internet mail alerts • Information services – in some areas, wide range of information including share prices, weather flight information, news headlines etc.

Disadvantage • Restricted to 160 characters.