4 Description

22.0933GPPCompletion of Calls to Busy Subscriber (CCBS)Release 17Service description, Stage 1TS

When subscriber A encounters a Network Determined User Busy (NDUB) destination B, subscriber A can request the CCBS supplementary service (i.e. activate a CCBS Request against destination B). The network will then monitor the wanted destination B for becoming idle.

When the wanted destination B becomes idle, then the network will wait a short time in order to allow destination B to make an outgoing call. If destination B does not make any outgoing call within this time, then the network shall automatically recall subscriber A.

When subscriber A accepts the CCBS recall, within a defined time, then the network will automatically generate a CCBS call to destination B.

CCBS has to be supported by the originating, as well as by the terminating network.

4.1 Applicability to telecommunications services

The applicability of the CCBS supplementary service is defined in TS 22.004 [2].