13. 4G LTE - RF Operational Parameters| Page 13 Hand Over in
LTE Network
14. 4G LTE - RF Operational Parameters| Page 14 Overview of
Handover While moving, a UE performs the handover procedure to
change connection to the network. The following figure shows the
schematic diagram. In the LTE system, the handover procedure is
controlled by the network (eNodeB). Therefore, the eNodeB needs to
monitor the quality of the radio environment where the UE is in. To
do so, the eNodeB delivers a measurement control instructing the UE
to send measurement reports when the conditions specified in the
measurement control are met. Trigger: Currently, Huawei eNodeB uses
event A3 to trigger an intra-frequency handover and events A2 and
A4 to trigger an inter- frequency handover. Handover: The eNodeB
delivers the handover command to the UE. Upon reception of the
handover command, the UE disconnects from the source cell and is
handed over to the target cell.
15. 4G LTE - RF Operational Parameters| Page 15 Overview of
Handover Handovers in the LTE system Intra-RAT handovers Frequency
relationship: Intra-frequency handovers Inter-frequency handovers
Signaling bearers: Intra-eNodeB handovers Intra-MME X2-based
handovers (in case the X2 interface is configured) Intra-MME
S1-based handovers (in case the X2 interface is not configured)
Inter-MME S1-based handovers with data forwarding over the X2
interface (in case the X2 interface is configured) Inter-MME
S1-based handovers with data forwarding over the S1 interface (in
case the X2 interface is not configured) Inter-RAT handovers
17. 4G LTE - RF Operational Parameters| Page 17 Handover
Success Rate According to the signaling process in 3GPP TS 36.331,
eNodeB statistics (1) Handover success rate = Number of
handovers/Number of handover attempts x 100% (2) Number of handover
attempts: indicates the number of eNodeB-transmitted
RRCConnectionReconfiguration messages for handovers. (3) Number of
handovers: indicates the number of eNodeB-received
RRCConnectionReconfigurationComplete messages for handovers.
Handover success rate The handover success rate is greater than 97%
at the TD-LTE site in Norway. The handover success rate is 100% in
the Huayang field in Chengdu.
19. 4G LTE - RF Operational Parameters| Page 19 ANR vs UE
capability : Inter-eNodeB 1. The source eNodeB delivers the
intra-frequency measurement configuration to the UE, instructing
the UE to measure neighboring cells that work on the frequencies
specified in the measurement configuration. 2. The UE detects that
the PCI of cell B meets the measurement requirements, and reports
the PCI to the source eNodeB. 3. The source eNodeB checks whether
its intra-RAT NCL includes the PCI of cell B. If so, the procedure
ends. If not, the source eNodeB sends the measurement configuration
to the UE, instructing the UE to read the ECGI, tracking area code
(TAC), and PLMN ID list of cell B. 4. The source eNodeB allows the
UE to read these parameters over the broadcast channel (BCH). 5.
The UE reports the obtained parameter values to the source eNodeB.
Notes: ANR features of an UE will effect the capability of the UE
to read the ECGI, TAC and other information of the target cell.
Thus, failure to do so the target cell information cant be
read.
20. 4G LTE - RF Operational Parameters| Page 20 Due to the
source cell and target cell are located under the same BBU board,
thus target cell information can be search and obtain internally
referring to the PCI. Therefore although UE doesnt support ANR
features, it doesnt affect the reading of ECGI, TAC and other
information of the target cell which required for the creation of
NCL. 1. The source eNodeB delivers the intra-frequency measurement
configuration to the UE, instructing the UE to measure neighboring
cells that work on the frequencies specified in the measurement
configuration. 2. The UE detects that the PCI of target cell (Cell
A) meets the measurement requirements, and reports the PCI to the
source cell (Cell B). ANR vs UE capability : Intra-eNodeB
21. 4G LTE - RF Operational Parameters| Page 21 Power Control
Overview
22. 4G LTE - RF Operational Parameters| Page 22 Power Control
Overview