Cell Broadcast (CB) is a method of sending messages to multiple mobile telephone users in a defined area at the same time. It is defined by the ETSIs GSM committee and 3GPP and is part of the 2G, 3G, 4G LTE, and 5G standards. CB messages are geo-targeted and geo-fenced, meaning they are one-to-many messages sent to a specific area. Unlike Short Message Service-Point to Point (SMS-PP), which is a one-to-one messaging service, CB is a one-to-many messaging service. CB messages are used for public warning messages, such as severe weather alerts, natural and man-made disasters, or pandemics.

CB messages contain broadcasting schedules, and the repetition rate can be set between 2 seconds and values beyond 30 minutes. Each repeated CB message will have the same message identifier and the same serial number, allowing mobile phones to identify and ignore broadcasts of already received messages. A CBC sends CB messages, a list of cells where messages are to be broadcast, and the requested repetition rate and number of times they shall be broadcast to the BSC/RNC/MME/AMF. The BSCs/RNCs/MME/AMF responsibility is to deliver the CB messages to the base stations (BTSs), Node Bs, ENodeBs, and gNodeBs that handle the requested cells.

To stop receiving CB messages, users can go to the messaging app, tap the menu key, and select settings. CB messages are part of the GSM standard and have been designed to deliver messages to multiple users in an area. The technology is also used to push location-based subscriber services or to communicate the area code of Antenna cell using Channel 050.