Message Service (SMS)

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[1] as a means of sending messages of up to 160 characters (including spaces), to and from GSM mobile handsets.[2] 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.[citation needed] Most SMS messages are mobile-to-mobile text messages, though the standard supports other types of broadcast messaging as well. Contents[hide] [edit] History [edit] 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. Experts from several of those communities, contributed in the discussions on which should be the GSM services. Most thought 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",[1] 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".[3] 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.[4] MAP Phase 2 expanded support for SMS by introducing a separate operation code for Mobile Terminated Short Message transport.[5] 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,[6] while CAMEL Phase 4, as part of 3GPP Release 5 and onwards, provides the IN with the ability to control the Mobile Terminated service.[7] CAMEL allows the gsmSCF 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[8] was sent over the Vodafone GSM network in the United Kingdom on 3 December 1992, from Neil Papworth of Sema Group (now Airwide Solutions) using a personal computer to Richard Jarvis of Vodafone using an Orbitel 901 handset. The text of the message was "Merry Christmas".[9] The first SMS typed on a GSM phone is claimed to have been sent by Riku Pihkonen, an engineering student at Nokia, in 1993.[10] The first commercial deployment of an SMSC was by Logica (now Acision) with Fleet Call (now Nextel) in Los Angeles, in June of 1993, followed by Telenor in Norway[citation needed] and BT Cellnet (now O2 UK) later in 1993. . Initial growth was slow, with customers in 1995 sending on average only 0.4 messages per GSM customer per month.[11] 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[citation needed]. 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,[11] and by Christmas Day 2006, over 205m texts were sent in the UK alone.[12] 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[citation needed]. SMS was originally designed as part of GSM, but is now available on a wide range of networks, including 3G networks. However, not all text messaging systems use SMS, and some notable alternate implementations of the concept include J-Phone's SkyMail and NTT Docomo's Short Mail, both in Japan. E-mail messaging from phones, as popularized by NTT Docomo's i-mode and the RIM BlackBerry, also typically use standard mail protocols such as SMTP over TCP/IP. SMS derives its benefit from ubiquity (every modern cellphone can use it) and simplicity (there is no separate "SMS address" to learn, as with email)[citation needed]. These usability advantages balance the fact that SMS messages are occasionally delayed or even dropped; in practice, most messages arrive fairly quickly[citation needed]. Commercially SMS is a massive industry in 2006 worth over 80 billion dollars globally.[13] SMS has an average global price of 0.11 USD and maintains a near 90% profit margin.[14] The matter of addictiveness of SMS text messaging was first suggested by Nokia in its 2001 global messaging study[citation needed]. Ahonen in his book M-Profits in 2002 claimed that SMS was addictive and gave the reason for it to be "Reachability" ("Tavoitettavuus"). The first university study proof of the addiction was by the Catholic University of Leuven in Belgium in 2004 and a follow-up study by the Queensland University of Australia confirmed the finding and added that SMS text messaging was as addictive as cigarette smoking. Young people who suffer from SMS addiction show instances of lack of sleep (20% of youth wake up regularly to incoming SMS) and feelings of loneliness and insignificance if not receiving SMS messages[citation needed]. Addicted users also feel compelled to check the phone constantly to see if messages have arrived[citation needed]. There is growing belief that Blackberry wireless email users are showing similar addictive signs as SMS messaging users have[citation needed]. [edit] Technical details [edit] GSM Main article: Short message service technical realisation (GSM) The Short Message Service - Point to Point (SMS-PP) is defined in GSM recommendation 03.40.[2] GSM 03.41 defines the Short Message Service - Cell Broadcast (SMS-CB) which allows messages (advertising, public information, etc.) to be broadcast to all mobile users in a specified geographical area.[15] Messages are sent to a Short Message Service Centre (SMSC) which provides a store-and-forward mechanism. It attempts to send messages to their recipients. If a recipient is not reachable, the SMSC queues the message for later retry. Some SMSCs also provide a "forward and forget" option where transmission is tried only once. Both Mobile Terminated (MT), for messages sent to a mobile handset, and Mobile Originating (MO), for those that are sent from the mobile handset, operations are supported. Message delivery is best effort, so there are no guarantees that a message will actually be delivered to its recipient and delay or complete loss of a message is not uncommon, particularly when sending between networks. Users may choose to request delivery reports, which can provide positive confirmation that the message has reached the intended recipient. Transmission of short messages between the SMSC and the handset is done using the Mobile Application Part (MAP) of the SS7 protocol. Messages are sent with the MAP mo- and mt-ForwardSM operations, whose payload length is limited by the constraints of the signalling protocol to precisely 140 octets (140 octets = 140 * 8 bits = 1120 bits). Short messages can be encoded using a variety of alphabets: the default GSM 7-bit alphabet (shown below), the 8-bit data alphabet, and the 16-bit UTF-16/UCS-2 alphabet.[16] Depending on which alphabet the subscriber has configured in the handset, this leads to the maximum individual Short Message sizes of 160 7-bit characters, 140 8-bit characters, or 70 16-bit characters (including spaces). Support of the GSM 7-bit alphabet is mandatory for GSM handsets and network elements,[16] but characters in languages such as Arabic, Chinese, Korean, Japanese or Cyrillic alphabet languages (e.g. Russian) must be encoded using the 16-bit UCS-2 character encoding (see Unicode). Routing data and other metadata is additional to the payload size
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