8.3.5 Hard handover

25.3313GPPProtocol specificationRadio Resource Control (RRC)Release 17TS

When performing hard handover with change of frequency, the UE shall:

1> clear the variable "Adjacent frequency info", "Inter-band frequency info" and "Frequency info list for enhanced measurement" if any of them is stored in CELL_INFO_LIST;

1> stop all intra-frequency and inter-frequency measurement reporting on the cells listed in the variable CELL_INFO_LIST. Each stopped measurement is restarted when a MEASUREMENT CONTROL message is received with the corresponding measurement identity.

8.3.5.1 Timing re-initialised hard handover

8.3.5.1.1 General

The purpose of the timing re-initialised hard handover procedure is to remove all the RL(s) in the active set and establish new RL(s) along with a change in the CFN in the UE according to the SFN of the target cell.(see subclause 8.5.15).

For TDD timing re-initialised hard handover is realised via CFN calculation (see subclause 8.5.15.2).

NOTE: For FDD, during the hard-handover procedure, the UE will align the timing of the uplink transmission as specified in [26].

This procedure is initiated when UTRAN does not know the target SFN timing before hard handover.

8.3.5.1.2 Initiation (FDD only)

Timing re-initialised hard handover initiated by the UTRAN is normally performed by using the procedure "Physical channel reconfiguration" (subclause 8.2.6), but may also be performed by using either one of the following procedures:

– "radio bearer establishment" (subclause 8.2.1);

– "Radio bearer reconfiguration" (subclause 8.2.2);

– "Radio bearer release" (subclause 8.2.3); or

– "Transport channel reconfiguration" (subclause 8.2.4).

In this case of a timing re-initialised hard handover, UTRAN should include the IE "Default DPCH Offset Value" and:

1> in FDD mode:

2> if the UE is configured for DPCH:

3> set "Default DPCH Offset Value" and "DPCH frame offset" respecting the following relation

(Default DPCH Offset Value) mod 38400 = DPCH frame offset_j

– where j indicates the first radio link listed in the message and the IE values used are the Actual Values of the IEs as defined in clause 11.

2> if the UE is configured for F-DPCH:

3> set "Default DPCH Offset Value" and "DPCH frame offset_j" respecting one of the following relations:

4> (Default DPCH Offset Value) mod 38400 = DPCH frame offset_j; or

4> (Default DPCH Offset Value+256) mod 38400 = DPCH frame offset_j,

– where j indicates the first radio link listed in the message and the IE values used are the Actual Values of the IEs as defined in clause 11.

If the IE "Default DPCH Offset Value" is included, the UE shall:

1> in FDD mode:

2> if the UE is configured for DPCH:

3> if (Default DPCH Offset Value) mod 38400 = DPCH frame offset_j,

– where j indicates the first radio link listed in the message:

4> set DOFF (see subclause 8.5.15.1) to Default DPCH Offset Value.

3> else:

4> set the variable INVALID_CONFIGURATION to TRUE.

2> if the UE is configured for F-DPCH:

3> if (Default DPCH Offset Value) mod 38400 = DPCH frame offset_j,

– where j indicates the first radio link listed in the message:

4> set DOFF (see subclause 8.5.15.1) to Default DPCH Offset Value.

3> else if (Default DPCH Offset Value+256) mod 38400 = DPCH frame offset_j,

– where j indicates the first radio link listed in the message:

4> set DOFF (see subclause 8.5.15.1) to Default DPCH Offset Value + 256.

3> else:

4> set the variable INVALID_CONFIGURATION to TRUE.

If the IE "Default DPCH Offset Value" is not included, the UE shall:

1> set the variable INVALID_CONFIGURATION to TRUE.

8.3.5.2 Timing-maintained hard handover

8.3.5.2.1 General

The purpose of the Timing-maintained hard handover procedure is to remove all the RL(s) in the active set and establish new RL(s) while maintaining the CFN in the UE.

For TDD timing re-initialised hard handover is realised via CFN calculation (see subclause 8.5.15.2).

NOTE: For FDD, during the hard-handover procedure, the UE will align the timing of the uplink transmission as specified in [26].

This procedure can be initiated only if UTRAN knows the target SFN timing before hard handover. The target SFN timing can be known by UTRAN in the following 2 cases:

– UE reads SFN when measuring "Cell synchronisation information" and sends it to the UTRAN in MEASUREMENT REPORT message.

– UTRAN internally knows the time difference between the cells.

8.3.5.2.2 Initiation (FDD only)

Timing-maintained hard handover initiated by the network is normally performed by using the procedure "Physical channel reconfiguration" (subclause 8.2.6), but may also be performed by using either one of the following procedures:

– "radio bearer establishment" (subclause 8.2.1);

– "Radio bearer reconfiguration" (subclause 8.2.2);

– "Radio bearer release" (subclause 8.2.3); or

– "Transport channel reconfiguration" (subclause 8.2.4).

In this case of a timing maintained hard handover procedure the UTRAN should not include the IE "Default DPCH Offset Value".

If the IE "Default DPCH Offset Value" is included, the UE shall:

1> ignore the IE "Default DPCH Offset Value".