Cell broadcast (CB) is a variant of the short message service( SMS) that is used in mobile networks of all generations. In other words, in GSM networks, UMTS networks, LTE networks and 5th generation mobile networks( 5G). It is a push service in which the message is primarily pushed to all mobile devices switched on in the selected radio cell.
With Cell Broadcast, an alphanumeric message is sent to one or more selected radio cells. The regional area in which the mobile devices see the cell broadcast is called the cell broadcast area. The number of radio cells can be defined by the information provider. All cellular receivers - cell phones, smartphones- within this cell broadcast area receive the same CB message, which can consist of up to 1,395 characters. Each message is composed of up to 15 pages, where each page in turn can have 93 alphanumeric characters or a total of 82 bytes in length. In total, Cell Broadcast can support `2^16` broadcast channels, or 65,536.
Cell broadcast is used in emergency situations, disasters and for general warning messages.