User`s guide

Agilent PXT Wireless Communications Test Set
User’s Guide
179
The PS handover can then be initiated via the 8960 UI when the UE is PDP active.
Only when performing the TAU procedure will IP connectivity be preserved
during the PS handover.
PS Handovers from LTE to UTRAN/GERAN
PS Handovers require the target cell to setup dedicated resources for an incoming UE. The source cell
queries the target cell for the resource configuration, and then communicates this information to the UE to
enable it to access the target cell. This technique bypasses the connection setup procedures and
subsequently minimizes the data flow interruptions.
For the PXT/8960 this process must be performed in two phases.
The first phase is to setup the 8960 for the requirements of the test (which may be nothing). The LTE
scenario is configured as normal, and the UE attached to the stage where a PS handover is performed. At
this point, the 8960 is set up for an inbound PS handover (refer to WCDMA PS Handovers
or
GSM/GPRS/EGPRS Documentation
). The 8960 queries the EPC for a description of the NAS resources
allocated to the UE, and then enters into a ‘Handover’ state. The transparent-hex string describing the
waiting resources can be retrieved via SCPI.
Phase two involves modifying the scenario file used in phase one. A MobilityFromEUTRACommand is
added, with the targetRAT-Type being utra or geran and the targetRAT-MessageContainer set to the
transparent-hex string retrieved above. This message is added as a Handover message on the Extended
tab of the N6062A Protocol Message Editor software application. The scenario should be reloaded and the
UE re-attached to the same point as before. Again, the 8960 is set up for an inbound PS handover.
The handover message is now sent to the UE which performs the PS handover to the legacy 3GPP
network.
NOTE: Phase One is only required once per test configuration, and is necessary only to retrieve the
transparent-hex string describing the 8960 waiting resources.
Only when performing the RAU procedure will IP connectivity be preserved
during the PS handover.
When performing PS Handovers to UTRAN/GERAN, only one (default) bearer
may be active on the LTE cell.
Performing RRC Release with Redirection
The RRC Release with Redirection involves adding an rrcConnectionRelease message to the scenario file.
The redirectedCarrierInfo must have the type utra-TDD or utra-FDD and frequency as set on the 8960. This
message is also added as a Handover message on the Extended tab of the N6062 Message Editor software
application.
Send the redirection message to the UE when on the LTE cell.
Only when performing the RAU procedure will IP connectivity be preserved
during an LTE to WCDMA redirection.
Refer to WCDMA RRC Release with Redirect (8960 documentation) for details on redirection from UTRAN
to LTE.