realtime application (RTA)

Real-time operations are time-critical applications. In general, one speaks of real-time behavior when the triggered operation has only a known delay, which is generally so short that it does not affect the application or human perception.

Real-time applications are mainly found in process automation, but also in data and telecommunications. Here, the aim is to keep transmission delays very low so that communication is not impaired. When and how the sensation is impaired essentially depends on the services being transmitted: whether telephony or video transmission, file transfer or hi-fi. Moving image transmissions react particularly critically to such delays, but so do applications where fractions of a second matter.

Since transmission networks have runtimes and latencies, real-time applications are particularly critical and can only be guaranteed in some network constellations via quality of service. This applies in particular to IP networks. For IP services such as Internet television( IPTV), voice over IP( VoIP), video over IP, live streaming, online games, community storage solutions, chats, instant messaging( IM) or multimedia over IP( MoIP), priority mechanisms with minimum delay times can only be guaranteed via quality of service ( QoS). Whether an application is a real-time application depends on the worst case execution timing(WCET). This is the worst-case execution time that a given application requires for realization.

An interesting approach for mobile communications is New Radio( NR), a 5th generation mobile communications service( 5G NR), in which a latency of 1 ms is specified.