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-ext-MODUL:09b

UCS-2

UCS-2 (2-byte Universal Character Set)

• The UCS-2 encoding form is identical to that of UTF-16(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.


http://en.wikipedia.org/wiki/Universal_Character_Set

http://en.wikipedia.org/wiki/Bit

http://en.wikipedia.org/wiki/Universal_Character_Set

http://en.wikipedia.org/wiki/Comparison_of_Unicode_encodings

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


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.


MS BSS MSC VLR InterworkingMSC

1 CHANNEL REQUEST <RACH>

<AGCH>DCCH ASSIGN

SIGNALING LINK

ESTABLISHED

SC

MO SMS TransferMO SMS Transfer




<AGCH>DCCH ASSIGN

<SDCCH>

SIGNALING LINK

ESTABLISHED

2 REQ. FOR SERVICE CR

CC

SC





<AGCH>DCCH ASSIGN

<SDCCH>

SIGNALING LINK

ESTABLISHED

2 REQ. FOR SERVICE CR

CC

3 AUTHENTICATION

SET Cipher MODE

SC



MS BSS MSC VLRInterworkingMSC


<AGCH>DCCH ASSIGN

<SDCCH>

SIGNALING LINK

ESTABLISHED

2 REQ. FOR SERVICECR

CC

3 AUTHENTICATION

SET Cipher MODE

SC

4 RP_MO_DATA

SIF_MO_SMS

SIF_MO_SMS-Ack



5 MO_Forward_SM

Short_Message

MO_Forward_SM_Ack

Short_Message_Ack

(SC_No.)


MS BSS MSC VLRInterworkingMSC

SC


5 MO_Forward_SM

Short_Message

MO_Forward_SM_Ack

Short_Message_Ack

6 RP_ACK

(SC_No.)



SC

"Send Successfully" is displayed on the mobile


MT SMS TransferMT SMS Transfer

For Forwarding a Short Message

For Forwarding Several Short Message


MSServicing

MSC VLR HLR GatewayMSC SC

1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM

MT SMS Transfer (A Message)MT SMS Transfer (A Message)


MSServicing


1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM

2 SIF_MT_SMS

Page

Page



MSServicing


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



MSServicing


1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM

2 SIF_MT_SMS

Page

Page Request

3 Paging Response


4 Short_Message

Short_Message_Ack

MT_Forward_SM_Ack

Short_Message_Ack



MSServicing


1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM

MT SMS Transfer (Several Messages)MT SMS Transfer (Several Messages)

MT_Forward_SM(The More message To

Send Flag is True)


MSServicing


1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM



Send Flag is True)

2 SIF_MT_SMS PagePaging Request


MSServicing


1 Short Message

SRI_For_SM

SRI_For_SM_Ack

MT_Forward_SM



Send Flag is True)

2 SIF_MT_SMS PagePaging Request

3 Paging Response



MSServicing


4 Short_Message

Short_Message_Ack

MT_Forward_SM_Ack

Short_Message_Ack



MSServicing


4 Short_Message

Short_Message_Ack

MT_Forward_SM_Ack

Short_Message_Ack


5 Short_Message

MT_Forward_SM


Send Flag is False)

Short_Message_Ack

MT_Forward_SM_Ack

Short_Message_Ack

Short_Message


MO_Forward_SM

Short_Message

MO_Forward_SM_Ack

Short_Message_Ack

RP_ACK

(SC_No.)


SC

"Send Not Successfully" is displayed on the mobile

AnswerAnswer

Illegal Subscriber

Illegal Subscriber


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.

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.

presentation on sms working

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