Mobile SystemSMS - 160 bytes that saved an industry

Johan Monteliusjm@sics.se

Overview

• Background– History of SMS, functionality, usage …

• Infrastructure– SMSC, SMPP, GSM 03.40 …

• Message format– 160 characters, Smart-messaging,

EMS …

In short• two-way

– terminals can both send and receive

• stor-and-forward– delivered when terminal is activated

• short message– 140 bytes or 160 7-bit characters

• available– mainly GSM systems but also in other

cellular systems

History

• Specified in GSM phase 1 standard• First public service in 1994• Roaming

– Slowly introduced in 1999

• Market takes off in 1999– 1 billion messages/month in Apr 1999– 3 billion messages/month in Dec 1999

Market growth

Telia in Norway and Sweden 2001

2 9

T e l ia A B , IR , 0 2 2 -2 0 0 2 , s v

T e l ia M o b ile

F o r t s a t t t i l lv ä x t fö r S M S

ja n fe b m a r a p r m a j ju n i ju li a u g s e p o k t n o v d e c

A n d e l a v o m s ä t tn in g e n Q 4S v e r ig e 4 % , N o r g e 1 3 %

A n d e l a v o m s ä t tn in g e n Q 4S v e r ig e 4 % , N o r g e 1 3 %

( m ilj o n e r m e d d e la n d e n )

0

3 0 0

6 0 0

9 0 0

N o r g e 2 0 0 1

N o r g e 2 0 0 0

S v e ri g e 2 0 0 1

S v e ri g e 2 0 0 0

Norway: 900M messages/ 1 M subs

Sweden: 400M messages/ 3,2 M subs

Norway: 13% of turnover

Sweden: 4% of turnover

Usage

• Operators report an average of 10-30 user originated messages per month.

• Traffic:– voice message notification– P2P messaging– ring tones / logos – sports scores– other information services

Premium SMS

Same request short-number (1985) regardless of operator.

Sender of request is charged 10 NOK.

Request sent as SMS message

Location based services

Request sent as SMS message

Operator dependant service

Will SMS be replaced?

Infrastructure

• MT – SMS capable terminal

• SMSC– Short message service centre

• Mobile network– Network to deliver the SMS

SMSC – the heart of SMS

SMSCIWMSC/GMSC

GSM Network

MT

MSC

MSC

MSC

SMSC Interface

MSC

SM-TPShort message transport protocol

GSM 03:40

GSM 04:11

GSM 09:02

HLR

SMSC

Fixed network

Not standardized by ETSI

the SMSC

• Vendors– CMG, Comverse, Logica, Sema Group

…

• Servers– Reliable, distributed– 2500 messages/s– Integrated billing support

Everyone wants a standard

Logica

Fixed networkTCP/IP X.25

SMPP

www.smsforum.net

UCP CIMD

OIS

Sema

CMGNokia

Intermediator

SMS format

• Specified in GSM 03:40 and 09:11• 140 bytes or 160 7-bit characters• Three types of messages:

– User: normal text messages– Mobile: OTA configuring– SIM: operator specific applications

Extensions to SMS

• Nokia: Smart messaging – OTA provisioning– ring tones, logos

• EMS Enhanced Messaging Service– 3GPP – Ericsson, Siemens, Alcatel , Motorola – ring tones, sound, logos, images,

animations, text style …

EMS

standard 7-bit characters

EMS header

- Content-Formating information, pre-defined or user supplied content.

- Pointers-Where in the text flow?

Do it yourself SMS interface

-Modem signaling using standard GSM phone