8.1.16 Inter RAT handover information transfer

25.3313GPPProtocol specificationRadio Resource Control (RRC)Release 17TS

Figure 8.1.16-1: Inter RAT handover information transfer, normal flow

8.1.16.1 General

The inter RAT handover information transfer procedure is used by the UE to convey RRC information needed for inter RAT handover to UTRAN.

8.1.16.2 Initiation

If:

– a radio access technology other than UTRA, e.g. GSM or E-UTRA, using radio access technology-specific procedures, orders the UE to provide the INTER RAT HANDOVER INFO message; or

– a radio access technology other than UTRA, e.g. GSM or E-UTRA, using radio access technology-specific procedures, configures the UE to send the INTER RAT HANDOVER INFO message upon system specific conditions not involving an explicit order e.g. early classmark sending upon entering connected mode; or

– while in connected mode using another radio access technology, the inter RAT handover info changes compared to what has previously been sent via the other radio access technology:

the UE shall:

1> initiate the inter RAT handover information transfer procedure.

To determine if the inter RAT handover info has changed compared to what has previously been sent, the UE shall:

1> store the information last sent in the variable INTER_RAT_HANDOVER_INFO_TRANSFERRED;

1> if this variable has not yet been set:

2> not initiate the inter RAT handover information transfer procedure due to change of inter RAT handover info.

NOTE: Currently neither the UE security information nor the predefined configuration status information change while in connected mode using GSM radio access technology.

8.1.16.3 INTER RAT HANDOVER INFO message contents to set

The UE shall:

1> if the UE supports both UMTS TDD and FDD:

2> determine whether capabilities are being requested for FDD or TDD mode; and

2> use the capabilities associated with that mode for the remainder of this procedure.

1> include the IE "UE security information", and the IE "UE security information2" if inter-RAT PS handover is supported by the UE; and

1> not include the IE "UE Specific Behaviour Information 1 interRAT";

1> in case support for the compressed version of the inter RAT handover info is indicated via the other radio access technology:

2> if the other radio access technology is not E-UTRA:

3> include of the following IEs the IE that after encoding has the smallest size: IE "Predefined configuration status information compressed" or the IE "Predefined configuration status information".

2> else:

3> exclude the IE "Predefined configuration status information" and "Predefined configuration status information compressed".

2> include the IE "UE radio access capability compressed".

1> else:

2> if the other radio access technology is not E-UTRA:

3> include the IE "Predefined configuration status information".

2> else:

3> exclude the IE "Predefined configuration status information".

2> include the IE "UE capability container", containing the IE "UE radio access capability" and the IE "UE radio access capability extension", in accordance with the following:

3> if the UE supports multiple UTRA FDD Frequency Bands; or

3> if the UE supports a single UTRA FDD Frequency Band different from Band I [21]; or

3> if the UE supports E-UTRA:

4> include the IE "UE radio access capability", excluding IEs "RF capability FDD" and "Measurement capability" for FDD and including the IE "Measurement capability TDD" for TDD;

4> include the IE "UE radio access capability extension", including the IEs "RF capability FDD extension", the "Measurement capability extension", the "Additional Secondary Cells", the "Additional Secondary Cells 2", the "Non-contiguous multi-cell", the "Support of uplink closed loop transmit diversity" and the "Support of uplink open loop transmit diversity" associated with each supported UTRA FDD frequency band indicated in the IE "Frequency band", but may omit all or part of these IEs for supported inter-RAT bands.

3> else:

4> include the IE "UE radio access capability", including the IEs "RF capability FDD" and "Measurement capability" associated with the Band I [21] for FDD and excluding the IE "Measurement capability TDD" for TDD;

4> include the IE "UE radio access capability extension", including the IEs "RF capability FDD extension", the "Measurement capability extension", the "Additional Secondary Cells", the "Additional Secondary Cells 2", the "Non-contiguous multi-cell", the "Support of uplink closed loop transmit diversity" and the "Support of uplink open loop transmit diversity" associated with each supported UTRA FDD frequency band indicated in the IE "Frequency band".

1> For FDD, include the IE "UE radio access capability comp 2";

1> For 1.28 Mcps TDD, include the IE "UE radio access capability comp for 1.28 Mcps TDD";

1> initiate the transfer of the INTER RAT HANDOVER INFO message via the other radio access technology, using radio access technology-specific procedures;

1> store the following in the variable INTER_RAT_HANDOVER_INFO_TRANSFERRED if they were included in the INTER RAT HANDOVER INFO message:

2> the IE "Predefined configuration status information";

2> the IE "Predefined configuration status information compressed";

2> the IE "UE security information";

2> the IE "UE security information2";

2> the IE "UE radio access capability";

2> the IE "UE radio access capability extension"; and

2> the IE "UE radio access capability compressed";

2> if the IE "UE radio access capability compressed" were included in the INTER RAT HANDOVER INFO message:

3> set the IE "Security Capability" to the mandatory R99 algorithms.

1> and the procedure ends.