6.16 RAN coordination

23.2213GPPArchitectural requirementsRelease 17TS

This applies to UTRAN only. The RAN coordinates the resource allocation of an UE attached to both PS and CS services. The UTRAN shall reject or downgrade a connection which cannot be granted, see TS 23.060 [2]. The cause might be congestion on the radio interface, or the existence of other connections between this UE and the other CN.

The RAN uses the IMSI to identify a UE. The IMSI is transferred from the CN to the RAN with the common ID procedure. When an Iu connection is established, the CN shall perform the RANAP common ID procedure toward RAN as soon as the UE is identified (IMSI). The IMSI is only stored in the RAN for the duration of the RRC Connection.

There are two functions that are co-ordinated.

1) Paging coordination is described in 5.9.1 of TS 25.410 [10]; and

2) Relocation coordination that is described in 8.7.5 in TS 25.413 [9].