Handover Procedures
Handover procedure is intended to reduce the interruption time, less than the circuit-switched handover in 2G networks, and it is an important function for LTE eNB. There are multiple Handover procedures to be tested shown Table 4. LTE eNB is required to implement handover procedure inside E-UTRAN (Inter eNB/Intra eNB) and also between legacy Radio Access Technologies (RAT) like UMTS.
| Handover | Description |
|---|---|
| Inter eNB Handover (Source) | Handover inside E-UTRAN. Procedure that side of UE leaving out from the cell. |
| Inter eNB Handover (Target) | Handover inside E-UTRAN. Procedure that side of UE coming into the cell. |
| Inter RAT Handover (Source) | Handover from E-UTRAN to different RAT. Procedure that side of UE leaving out from the cell. |
| Inter RAT Handover (Target) | Handover from E-UTRAN to different RAT. Procedure that side of UE coming into the cell. |
| Intra eNB Handover (Source) | Handover inside the same E-UTRAN cell. Procedure that side of UE leaving out from the sector. |
| Intra eNB Handover (Target) | Handover inside the same E-UTRAN cell. Procedure that side of UE coming into the sector. |
Test Configurations
Test configuration for Inter eNB Handover and Inter RAT Handover is shown in Figure 32. There are two types of procedures that can be tested in this configuration. The first type of the procedure is the “Source” where UE leaves out of the cell, and the other is the “Target” where UE comes into the cell. The eNB (DUT) is connected to S1/X2 Simulator with X2AP and S1AP interface, and it is also connected to UE Simulator as UE in the Cell. “Source” and “Target” procedures can be tested with same configuration. “Inter RAT (Source)” and “Inter RAT (Target)” can also be tested in this configuration.
Test configuration for Intra eNB Handover is shown in Figure 33.
Inter eNB Handover (Source) is shown in Figure 34.
Inter eNB Handover (Source) procedure is shown in Figure 35, Figure 36 and Figure 37.
Inter eNB Handover (Target) is shown in Figure 38.
Inter eNB Handover (Target) procedure is shown in Figure 39, Figure 40 and Figure 41.
Inter RAT (Radio Access Technology) Handover (Source) is handover between LTE and different radio access technology, i.e., UMTS. The test configuration and procedures are exactly the same as Inter eNB Handover (Source).
The test configuration and procedures for Inter RAT Handover (Target) is exactly the same as Inter eNB Handover (Source).
Intra eNB Handover is shown in Figure 42.
Inter eNB Handover procedure is shown in Figure 43
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