BACKGROUND
Short Messaging Service
Text messaging uses the short messaging service (100-200 characters in length) and involves sending text messages between phones. Examples include "C U L8ER" and "OK. AT FLAT OR OFFICE". It is quick and dirty, hard to use the keypad, abrupt, punctuation challenged, and incredibly useful and popular. Text messaging also has a lot of advantages such as convenience, available on all phones, and discrete.
Text messaging is something that is most prevalent in the youth market and especially teenagers, who are able to manipulate the difficulty of entering text with the mobile phone keypad. In fact, it is suspected that this steep learning curve and the necessary insider knowledge are some of the things that appeal to the youngsters (Bennett & Weill, 1997).
SMS advantages
Today's SMS has several advantages inherent in its fundamental features:
Store and forward This means that in the case that the recipient is not available, the short message is stored. Once the data is prepared and ready to send, SMS has advantages over packet data in that the burden of delivering the data is on the SMS center rather than the end user . The transaction costs incurred by the sender using SMS are therefore likely to be lower than a GPRS transaction.
Confirmation of delivery This means that the user knows that the short message has arrived. In the circuit switched data environment, there is an end-to-end connection and therefore the user knows that a connection has been established and the data is being transferred. In a GPRS environment, however, the concept is "always on" and this requires the user to find out whether the data has been sent or received.
SMS disadvantages
However, today's SMS also has several disadvantages:
Limited message length The unit short message length is currently limited to 140 octets because of limitations in the signalling layer. It would be preferable to have a length that is several times this magnitude. Packet data services such as GPRS simplify non-voice transactions over mobile networks because the amount of data that can be communicated in any one session is significantly higher.
Inflexible message structure The structure of the SMS protocol data unit as defined in the GSM 03.40 standard is inflexible. The data coding scheme, origination address, protocol identifier, and other header fields are fixed ‚ this has constrained the number of possible scenarios that can be indicated when developing applications.
Relatively slow signalling channel The latency turnaround time of services such as GPRS and unstructured supplementary services data (USSD) tends to be faster than that for SMS. The signalling channel is used for several other purposes besides SMS, such as locating phones and managing call completion. Indeed, as SMS traffic volume grows, network operators have expressed some concern about potential service outages due to the overuse of and corresponding degradation in the scarce signalling resources.
Always store and forward Today's SMS is designed such that every short message always passes through the SMS center. Variations on this have been discussed at the UMTS committee level, such as forwarding messages and optionally storing them: immediately attempt delivery and if the message cannot be delivered, then store it. This reduces the processing power needed by the SMS center.
Enhanced Messaging Service
The enhanced messaging service (EMS) is the ability to send a combination of simple melodies, pictures, sounds, animations, modified text, and standard text as an integrated message for display on an EMS-compliant handset. For example, a simple black-and-white image could be displayed along with some text and a melody could be played at the same time. EMS is an enhancement to SMS but is very similar to SMS in terms of using the store-and-forward SMS centers and the signalling channel.
EMS advantages
With the new, powerful EMS functionality, mobile phone users can add life to SMS text messaging in the form of pictures, animations, sound, and formatted text. As well as messaging, users will enjoy collecting and swapping pictures and ring signals and other melodies, downloading them from the Internet, or editing them directly on the phone.
Familiar user interface (UI) Users will find EMS as easy to use as SMS. EMS provides a familiar user interface and compatibility with existing phones.
Compatible with SMS standards An EMS message can be sent to a mobile phone that does not support EMS or only partially supports EMS. All the EMS elements are located in the message header. A receiving phone that does not support the standard will ignore the EMS contents. Only the text message will be displayed to the receiver.
No new network infrastructure needed The beauty with EMS is that it uses existing SMS infrastructure and industry standards, keeping investments to a minimum for operators.
Concatenated messages SMS concatenation ‚ stringing several short messages together ‚ will be the key technical feature to enable the enhanced messaging service for the simple reason that complicated enhanced message designs, such as sending every alternate character in bold format, would occupy a large number of octets.
Multimedia Messaging Service
Overview of MMS
The multimedia messaging service, as its name suggests, is the ability to send and receive messages comprised of a combination of text, sounds, images, and video to MMS-capable handsets (MMS architecture, 2002). The trends for the growth in MMS are taking place at all levels within GSM (Patel & Gaffney, 1997), enabling technologies such as GPRS, EDGE, 3G, Bluetooth (http://www.bluetooth.com/), and wireless access protocol (WAP; WAP & MMS specifications, 2002).
MMS, according to the 3GPP standards (3GPP TS 23.140, 2002) is "a new service, which has no direct equivalent in the previous ETSI/GSM world or in the fixed network world". Here is an introduction to the features of this innovative new service:
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MMS is a service environment that allows different kinds of services to be offered , especially those that can exploit different media, multimedia, and multiple media.
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MMS will enable messages to be sent and received using lots of different media, including text, images, audio, and video.
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As more advanced media become available, more content-rich applications and services can be offered using the MMS service environment without any changes.
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The multimedia messaging service (MMS) introduces new messaging platforms to mobile networks in order to enable MMS. These platforms are the MMS relay, MMS server, MMS user databases, and new WAP gateways.
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MMS will require not only new network infrastructure but also new MMS-compliant terminals. MMS will not be compatible with old terminals, which means that before it can be widely used, MMS terminals must reach a certain penetration.
MMS versus e-mail
Four key areas best illustrate the differences between MMS and e-mail messages:
Message creation Conventional e-mail evolved from a simple text-based communication tool to include multimedia content, primarily in the form of attachments. A mobile device's form factor and the use of mobile data service, such as e-mail, become extremely unwieldy for the end user. MMS has been standardized specifically to take the limitations of mobile devices and the mobile end-users' needs into account.
Message delivery Conventional e-mail is designed around a store-and-retrieve model, whereas technologies such as SMS and MMS operate on a store-and-forward model. When sending a message using the former model, the sender must wait for the receiver to come online and access the network to retrieve the message. With the MMS model the message is stored and " pushed " or forwarded to the receiver immediately or as soon as the receiver comes online.
Messaging interoperability Today, e- mails can contain numerous and varied media formats and/or types. Each media type generally requires tools/plugins to render that media usable. In the desktop environment these tools are available locally or via the intra/Internet. This is not the case for the mobile subscriber due to the limited set of media-rendering capabilities available on mobile devices.
Message billing Conventional e-mail billing has relied on the subscription and/ or access time model for billing the subscriber, resulting in little or no revenue for the service providers in some markets. SMS, however, has worked using a per-message billing model. Since MMS is the service evolution of SMS, mobile operators can apply SMS-like billing models to MMS without adverse customer reaction.
Implications of SMS on MMS
The current short message service has some unique advantages that other non-voice services do not have, such as store and forward and confirmation of message delivery. However, SMS also has some disadvantages, such as limited message length, inflexible message addressing structures, and signalling channel slowness.
Implications of EMS on MMS
Messaging will certainly develop beyond SMS. It is clear that an elegant solution like EMS that builds on simple text messaging and adds sound and simple images is a useful and powerful development that takes us beyond the limited reach of smart messaging services. It is clear that multimedia messaging service provides an ideal migration path to take advantage of the capacity and bandwidth that 3G/UMTS networks supply.
| Feature | SMS | MMS |
|---|---|---|
| Store and Forward ( non-real -time) | Yes | Yes |
| Confirmation of message delivery | Yes | Yes |
| Communications type | Person to person | Person to person |
| Media supported | Text plus binary | Multiple ‚ text, voice, video |
| Delivery mechanism | Signalling channel | Data traffic channel |
| Protocols | SMS specific, e.g., SMPP | General Internet, e.g., MIME, SMTP |
| Platforms | SMS center | MMS relay plus others |
| Applications | Simple person to person | Still images |
To summarise, MMS offers the content richness of e-mail and the instantaneous delivery of SMS messaging. While e-mail provides greater levels of utility, it fails to provide the instantaneous sharing and presentational capabilities needed to make it truly the mobile mass-market service. The strength of MMS in these areas make MMS the premium mass-market messaging service in 2.5G and 3G networks.
