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)news.bbc.co.uk/1/hi/technology/3422475.stm 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 SCAService Centre Address MRMessage ReferencePIDProtocol Identifier PDU TypeProtocol Data Unit Type DADestination AddressDCSData Coding Scheme VPValidity PeriodUDLUser Data LengthUDUser Data
SMS & MMS SMS What a packet looks like Example SMS transmission packet saying “Hello” (www.spallared.com/nokia/smspdu/smspdu.htm#_Toc485435709, 2003)www.spallared.com/nokia/smspdu/smspdu.htm#_Toc485435709
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 Infrastructure Base Station Base Station 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 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 Infrastructure Base Station 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)www.w2forum.com/MMS_Extract.pdf 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 www.wmlclub.com/docs/especwap2.0/WAP-205- MMSArchOverview-20010425-a.pdf WAP Version 2.0 www.wapforum.org/what/WAPWhite_Paper1.pdf
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