SMS in GSM Explained: Origination to Cell Broadcast
SMS in GSM Explained: Origination to Cell Broadcast
As part of the Global System for Mobile Communications (GSM) the short message service (SMS) exists and provides a means to transfer short text messages between user equipment (UE) and a short message service center (SMSC) as described by Korhonen (2001). Messages are sent using the control signaling resources, and their maximum length is 160 characters. SMS is not a real-time service, as Korhonen (2001) point out, but store and forward service in which SMS messages can be stored on the SMSC and delivered when the destination UE is available. There are three essential services provided by SMS. They are Short Message Mobile Originated (SMS-MO), Short Message Mobile Terminated (SMS-MT) and Short Message Cell Broadcast (SMS-CB) as Korhonen (2001) discusses.
Mobile Originated and Mobile Terminated Messaging
In SMS-MO messaging, as Lin & Chlamtac (2001) discusses that a UE sends a short message to the SMSC and depending on the target of the message, the SMSC may deliver the message to another mobile station or a normal pager. What SMS-MT refers to an SMS message was mobile terminated SMS message as described by Korhonen (2001). In SMS-MT messaging, as Lin & Chlamtac (2001) describes, a mobile station receives a short message from the SMSC. The message sender can be another mobile station in the GSM network or an input device in a traditional paging system.
Cell Broadcast Service
The GSM specification includes a provision for SMS cell broadcast (SMS-CB) service as described by Korhonen (2001). The service provides SMS messages that are broadcast to all mobile stations in an area (one cell or a set of cells) as Korhonen (2001) points out. An enhanced version of this service called the cell broadcast service (CBS) would be used in UMTS networks. CBS can deliver much longer text messages than the GSM SMS-CB service as described by Korhonen (2001). A CBS message has a maximum size of 1,395 characters, and the messages can be received by all terminals capable of receiving CBS. Cell broadcast messages are assigned a message class type, which can be used by the UE to filter and receive only those messages, which, moreover, are of interest to the user as discussed by Korhonen (2001).
References
Korhonen, J. (2001). Introduction to 3G mobile communications. Boston: Artech House.
Lin, Y., & Chlamtac, I. (2001). Wireless and mobile network architectures. New York: John Wiley & Sons.