SMS &MMS

Justin Champion

C208 Ext:3723www.staffs.ac.uk/personal/engineering_and_technology/jjc1

SMS & MMS

Contents What is SMS

How it Works Infrastructure Required

What is MMS Infrastructure Required

SMS & MMS

Short Messaging Service (SMS) Also known as Simple Message Service

Intention Designed as a replacement for the Pager

The pager allows text messages to be sent to the device To respond you must get to a phone Still widely used, in

Hospitals Military Police Industry

SMS & MMS

SMS allowed Two way communications of the text messages Maximum character length of 160 characters

This can change though depending on the operator or the character set used Character sets supported are

ASCII + additional European characters Unicode

First Text Was sent in December 1992, to a Vodafone device

Sent by Neil Papworth, saying “Merry Christmas” Standard

Defined by ETSI and is known as “GSM 03.40”

SMS & MMS

SMS Continued The success is SMS was never planned for! It was only ever intended as the Pager replacement, with

limited use This will explain some of the design decisions made

Usage in the UK alone December 2003, 20.5 Billion messages sent over the four largest

operators (news.bbc.co.uk/1/hi/technology/3422475.stm, 2004)

Consider this at 8 Pence a time!

SMS & MMS

GSM At a defined time interval in GSM all devices will listen to a

transmission. This is when a Digital Control Channel (DCCH) packet of

information is being sent across the network. These DCCH packets are used to transfer essential information into

the devices. Information like a call is in coming Paging signals from the Base stations, to work out if a handover is

needed One of these packet formats is called SMS point to point messaging,

Paging, access control channel (SPACH) This message type can be used to carry a text message.

Advantage of this method is a text message can still be delivered during a phone conversation.

SMS & MMS

SMS Packet format All data is transferred in a single DCCH SPACH packet

SCA Service Centre Address

MR Message Reference PID Protocol Identifier

PDU Type Protocol Data Unit Type

DA Destination Address DCS Data Coding Scheme

VP Validity Period UDL User Data Length UD User Data

SMS & MMS SMS

What a packet looks like Example SMS transmission packet saying “Hello”(www.spallared.com/nokia/smspdu/smspdu.htm#_Toc485435709, 2003)

SMS & MMS

SMS delivery Takes no additional allocation of channels Will still work on a none packet switched infrastructure Device does not need to continuously listen for a SMS

delivery warning Using this DCCH format, SMS will work on a large number of

digital networks GSM - Europe PCS - American PDC - Japan

SMS & MMS

SMS Infrastructure One additional server needs adding to the GSM

network Short Message Service Centre (SMSC)

SMSC

GSM SMS InfrastructureBaseStation

BaseStation

HLR

HLR = Home Location Register

Other Mobile Phone

Network

SMS & MMS

SMSC This is a combination of hardware and software

The SMS message will be stored at this location on a FIFO basis If the messages destination is within the local network The HLR, is queried to find the current location of the intended

device The HLR will also inform if the device is currently turned on If the device is off then the HLR is informed that there is a

message waiting When the device turns on the HLR informs the SMSC The message will then be forwarded to the device

If the device is turned on, the message will be forwarded to that location

SMS & MMS

SMSC Device is outside of the network

The message will be forwarded to the SMSC of that network, where deliver will be the same as before

SMS & MMS Evolution Operators recognised the massive

potential of data services They looked at developing SMS

Result was Enhanced Messaging Service

Allowed additional data to be sent beyond SMS Text formatting

Multimedia Messaging Service Discussed in this lecture

SMS & MMS Evolution

SMS & MMS

Latest Technology Multimedia Messaging Service (MMS)

Allows the transfer of more than text between mobile devices These devices do not need to be compatible! In the event of a none compatible device being sent a

MMS, they will receive an Internet link instead The message can then be view on the Internet at a

later stage MMS

Is only available on GRPS devices and newer

SMS & MMS

MMS The following are the current standards

The standards can be expanded in the future This is a list of base requirements for devices to be given the title

of MMS compatible Pictures

JPEG, GIF, PNG, SVG-Tiny (2D Vector Graphics) Movies

MPEG-4 Sound

SP-MIDI Adaptive Multi Rate (AMR)

Text ASCII Text UTF 8/16

Future Use Allows unlimited expansion

SMS & MMS

MMS Additional information about how to present the

Media can also be transferred If this is not present the device will make the

decision Formats are WML, XML or SMIL

Synchronised Multimedia Integration Language (SMIL) SMIL allows for time dependent display of information Allowing for example a presentation to be shown on the

device

SMS & MMS

MMS Delivery SMS was delivered in a single packet MMS can have a theoretical unlimited

message size In reality the operators/devices will control the size

of the messages This indicates that the message can not be

delivered in a single packet Number of packets will depend on the type of

messages sent, as with TCP

SMS & MMS

MMS Transport MMS packets will be transferred using the

WAP protocol in GSM based networks This gives security in the messages Access to the Internet to move MMS message if

needed to the Internet The User agent at the application layer is

changed to deal with MMS Remember WAP is only a transport protocol

Your WML display is just another user agent

SMS & MMS

MMS Delivery continued MMS message will be transferred in the spare

capacity The media will be trickled to your device You will only be informed of a message once all of the data

is in the device If you device does not have the storage to display a movie,

then the data can be streamed into your device Reducing the overhead for storage, but increasing the

overhead for the network. This will not be available until 3G (UMTS in Europe)

MMS is not platform dependent Meaning that any mobile system can use this technology

SMS & MMS

Paying for MMS ? SMS was simple the sender paid a set amount

This is now an issue with the potential large amounts of data to be sent

As MMS can in the future be linked to the Internet how will pay for data coming from it?

This is an issue which will need resolving Billing needs to be as simple as SMS to be effective

Users do not want to get a bill which says you have received 0.65 Mbytes of data to most people it means nothing

SMS & MMS

MMS Infrastructure

MMSE

MMS InfrastructureBaseStation MMSE = MMS Environment

HLR

Internet

SMS & MMS Multimedia Messaging Service Environment (MMSE)

Generic name for all of the servers which need to provide information to send a MMS These can be in more than one network

Consider this when you are roaming MMS Centre (MMSC)

Storing the MMS message until delivery the same as SMSC MSS Relay

Allows delivery of information over different packet switched networks Records usage for charging Conversion of the messages

This will be based upon the specification of the device Using WAP 2.0

HLR Allows the discovery of the status/location of a device

MMS Value Added Services (VAS) Allowing the adding of high quality multimedia in a MMS, provided by the

operator

SMS & MMS

MMS Future The initial take up of MMS has not been as good as expected MMS sending is expected to be 1% of the market this year

(www.w2forum.com/MMS_Extract.pdf, 2004) Reasons

Uncertainty about the technology Expense Lack of MMS capable devices

The usage of MMS should increase This will reduce the cost of the messages MMS capable equipment will become available as people naturally

replace there phones Due to adverts the understanding of the technology is increasing

SMS & MMS

Link MMS standards document

www.wmlclub.com/docs/especwap2.0/WAP-205-MMSArchOverview-20010425-a.pdf

WAP Version 2.0 www.wapforum.org/what/WAPWhite_Paper1.pdf

SMS & MMS

Conclusion SMS MMS