6.9.4 PS Handover Procedure

23.0603GPPGeneral Packet Radio Service (GPRS)Release 17Service descriptionStage 2TS

The PS Handover procedure is used to handover an MS with one or more packet flows from a source cell to a target cell, when at least one of the cells is a GERAN cell. The source and target cells can be located within either the same BSS (Intra BSS HO), different BSSs within the same SGSN (Intra SGSN HO) or belonging to different SGSNs (Inter SGSN HO), or systems with different radio access types (Inter RAT HO, Inter mode HO).

While the MS is still in the source cell:

– Radio resources in the target cell are allocated and signalled to the MS.

– System information of the target cell needed for access in the target cell is signalled to the MS.

After handover between GERAN and UTRAN is complete, the RAU procedure is performed even if the RAI has not changed.

As specified in clause, "Support for Non-IP data", with regard to CIoT EPS Optimisations, PDP Contexts of PDN Type "Non-IP" and PDN Connection to SCEF may need to be handled during the PS Handover Procedure. For an MS that is using a "Non-IP" connection to a GGSN/PGW, or a PDP Context to a SCEF, if these PDP Contexts cannot be supported by the target SGSN, the source SGSN does not attempt to handover those bearers and releases them upon successful completion of the handover. If the MS does not have any PDP Context other than Non-IP or SCEF ones that can be transferred, then the SGSN sends failure message to the source RAN node.

The complete PS Handover procedures are defined in TS 43.129 [87].

The complete Inter RAT HO between E‑UTRAN and GERAN procedures are defined in TS 23.401 [89].