Friday, January 9, 2009

Short message service

Short Message Service (SMS) is a communications protocol allowing the interchange of short text messages between mobile telephone devices. SMS text messaging is the most widely used data application on the planet, with 2.4 billion active users, or 74% of all mobile phone subscribers sending and receiving text messages on their phones.The SMS technology has facilitated the development and growth of text messaging. The connection between the phenomenon of text messaging and the underlying technology is so great that in parts of the world the term "SMS" is used as a synonym for a text message or the act of sending a text message, even when a different protocol is being used.
SMS as used on modern handsets was originally defined as part of the GSM series of standards in 1985 as a means of sending messages of up to 160 characters (including spaces), to and from GSM mobile handsets.Since then, support for the service has expanded to include alternative mobile standards such as ANSI CDMA networks and Digital AMPS, as well as satellite and landline networks. Most SMS messages are mobile-to-mobile text messages, though the standard supports other types of broadcast messaging as well.

SMS as part of GSM
The idea of adding text messaging to the services of mobile users was latent in many communities of mobile communication services at the beginning of the 1980s. The person attributed for inventing the idea is Matti Makkonen then of Telecom Finland in 1984, who received the Economist Award for Innovation for this contribution in 2008. Mostthought of SMS as providing a means to alert the individual mobile user, for example, of a deposited voice mail, whereas others had more sophisticated applications in their minds, such as telemetry. However, few believed that SMS would be used as a means for sending text messages from one mobile user to another.
As early as February 1985, after having already been discussed in GSM subgroup WP3, chaired by J. Audestad, SMS was considered in the main GSM group as a possible service for the new digital cellular system. In GSM document "Services and Facilities to be provided in the GSM System", both mobile originated and mobile terminated short messages appear on the table of GSM teleservices.
The discussions on the GSM services were then concluded in the recommendation GSM 02.03 "TeleServices supported by a GSM PLMN".Here a rudimentary description of the three services was given:
Short message Mobile Terminated (SMS-MT)/ Point-to-Point: the ability of a network to transmit a Short Message to a mobile phone. The message can be sent by phone or by a software application.
Short message Mobile Originated (SMS-MO)/ Point-to-Point: the ability of a network to transmit a Short Message sent by a mobile phone. The message can be sent to a phone or to a software application.
Short message Cell Broadcast.
This was handed over to a new GSM body called IDEG (the Implementation of Data and Telematic Services Experts Group), which had its kickoff in May 1987 under the chairmanship of Friedhelm Hillebrand. The technical standard known today was largely created by IDEG (later WP4) as the two recommendations GSM 03.40 (the two point-to-point services merged together) and GSM 03.41 (cell broadcast).
The Mobile Application Part (MAP) of the SS7 protocol included support for the transport of Short Messages through the Core Network from its inception.MAP Phase 2 expanded support for SMS by introducing a separate operation code for Mobile Terminated Short Message transport.Since Phase 2, there have been no changes to the Short Message operation packages in MAP, although other operation packages have been enhanced to support CAMEL SMS control.
From 3GPP Releases 99 and 4 onwards, CAMEL Phase 3 introduced the ability for the Intelligent Network (IN) to control aspects of the Mobile Originated Short Message Service, while CAMEL Phase 4, as part of 3GPP Release 5 and onwards, provides the IN with the ability to control the Mobile Terminated service.CAMEL allows the gsmSCP to block the submission (MO) or delivery (MT) of Short Messages, route messages to destinations other than that specified by the user, and perform real-time billing for the use of the service. Prior to standardized CAMEL control of the Short Message Service, IN control relied on switch vendor specific extensions to the Intelligent Network Application Part (INAP) of SS7.
The first SMS message was sent over the Vodafone GSM network in the United Kingdom, from Neil Papworth of Sema Group using a personal computer to Richard Jarvis of Vodafone using an Orbitel 901 handset. The text of the message was "Merry Christmas".The first SMS typed on a GSM phone is claimed to have been sent by Riku Pihkonen, an engineering student at Nokia, in 1993.
Initial growth was slow, with customers in 1995 sending on average only 0.4 messages per GSM customer per month. One factor in the slow takeup of SMS was that operators were slow to set up charging systems, especially for prepaid subscribers, and eliminate billing fraud which was possible by changing SMSC settings on individual handsets to use the SMSCs of other operators
Over time, this issue was eliminated by switch-billing instead of billing at the SMSC and by new features within SMSCs to allow blocking of foreign mobile users sending messages through it. By the end of 2000, the average number of messages reached 35 per user per month,and by Christmas Day 2006, over 205m texts were sent in the UK alone.
It is also alleged that the fact that roaming customers, in the early days, rarely received bills for their SMSs after holidays abroad had a boost on text messaging as an alternative to voice calls

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