With Long Term Evolution (LTE), the pros most definitely outweigh the cons. This new and improved network will provide faster speeds and handle the ever-increasing data demands. Note every user, however, is ready for LTE. Both 3G and 2G networks are still in wide use and LTE must find a way to work with both, dealing with the handover that may arise.
There are many ways to handle this LTE handover. According to Artiza Networks, handover procedure, when working correctly, should 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 LTE handover procedures to be tested, shown below. LTE eNB must implement handover procedure inside E-UTRAN (Inter eNB/Intra eNB) and also between legacy Radio Access Technologies (RAT) like UMTS. [1]
Handover Procedures:
|
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 |
To break it down, technically, let’s look at an example, the Intra E-UTRAN Handover. This handover, according to LteWorld, is used to hand over a UE from a source eNodeB to a target eNodeB using X2 when the MME is unchanged. In this scenario, Serving GW is also unchanged. The presence of IP connectivity between the Serving GW and the source eNodeB, as well as between the Serving GW and the target eNodeB is assumed.
“The intra E-UTRAN HO in RRC_CONNECTED state is UE assisted NW controlled HO, with HO preparation signaling in E-UTRAN. To prepare the HO, the source eNB passes all necessary information to the target eNB and the UE accesses the target cell via RACH following a contention-free procedure using a dedicated RACH preamble. The HO procedure is performed without EPC involvement, i.e. preparation messages are directly exchanged between the eNBs. The figure below shows the basic handover scenario where neither MME nor Serving Gateway changes.” [2]
