An over-the-air update (OTA update) is a way of remotely distributing new software, configuration settings, and even encryption keys to devices like mobile phones, tablets, set-top boxes, cars or secure voice communication equipment (encrypted two-way radios). One important feature of OTA is that one central location can send an update to all the users, who are unable to refuse, defeat, or alter that update, and that the update applies immediately to everyone on the channel. A user could 'refuse' OTA, but the 'channel manager' could also 'kick them off' the channel automatically. In the context of the mobile content world, these include firmware-over-the-air (FOTA), over-the-air service provisioning (OTASP), over-the-air provisioning (OTAP), or over-the-air parameter administration (OTAPA); or provisioning handsets with the necessary settings with which to access services such as wireless access point (WAP) or Multimedia Messaging Service (MMS). As mobile phones accumulate new applications and become more advanced, OTA configuration has become increasingly important as new updates and services come on stream. OTA via Short Message Service (SMS) optimises the configuration data updates in subscriber identity module (SIM) cards and handsets, and enables the distribution of new software updates to mobile phones or provisioning handsets with the necessary settings with which to access services such as WAP or MMS. OTA messaging provides remote control of mobile phones for service and subscription activation, personalisation, and programming of a new service for mobile operators and telco third parties. Various standardisation bodies were established to help develop, oversee, and manage OTA. One of them is the Open Mobile Alliance (OMA). More recently, with the new concepts of Wireless Sensor Networks and the Internet of Things (IoT), where the networks consist of hundreds or thousands of nodes, OTA is taken to a new direction: for the first time OTA is applied using unlicensed frequency bands (868 MHz, 900 MHz, 2400 MHz) and with low consumption and low data rate transmission using protocols such as 802.15.4 and Zigbee. Sensor nodes are often located in places that are either remote or difficult to access. As an example, Libelium has implemented an OTA programming system for Zigbee WSN devices. This system enables firmware upgrades without the need of physical access, saving time and money if the nodes must be re-programmed. From Wikipedia
