1.26.1 LBFD-00201801 Coverage Based Intra-frequency Handover
Availability
This feature is available from eRAN1.0.
Summary
Handover functionality is important in any cellular telecommunications network. It is performed to ensure no disruption to services. Handover plays a significant role in LTE system performance since its main purpose is to decrease the
communication delay, enlarge the coverage and then enhance the system performance.
Intra-Frequency Handover enables a UE in connected mode to be served continuously when it moves across different cells that are operating at the same frequency.
Benefits
The coverage-based intra-frequency handover feature provides supplementary coverage in intra-frequency LTE systems to prevent call drop, enable seamless coverage and therefore improve the network performance and end user experience.
Description
This feature is one of the fundamental functions of an LTE system. The purpose of handover is to ensure that a UE in RRC-CONNECTED mode is served
continuously when it moves. Handover in LTE is characterized by the handover procedure in which the original connection is released before a new connection is set up.
Intra-frequency handover refers to the handover between cells operating at the same frequency band. It can be triggered by coverage or load. In eRAN1.0, the
coverage-based intra-frequency handover is supported.
The intra-frequency handover procedure can be divided into three phases:
handover measurement, handover decision, and handover execution.
E-UTRAN configures the handover-related measurement through the RRC Connection Reconfiguration message. The UE could measure either Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) for intra-frequency handover.
Upon receiving a measurement report from the UE, the eNodeB makes a handover decision according to certain triggering criteria. If a handover is required, the handover execution procedure will be invoked and the UE will be handed over from the source eNodeB to the target eNodeB. Huawei eRAN1.0 follows the intra-frequency handover procedures specified in 3GPP TS 36.300.
The following scenarios are considered in the intra-frequency handover:
Handover between two cells configured in the same eNodeB. No external neighbor is needed.
Handover between two cells configured in different eNodeBs with an X2 interface available. In this case, the source eNodeB sends a HANDOVER REQUEST message over the X2 interface.
Handover between two cells configured in different eNodeBs with no X2 interface available. In this case, the source eNodeB sends a HANDOVER REQUIRED message over the S1 interface.
Enhancement
None
Dependency
None
1.26.2 LBFD-00201802 Coverage Based Inter-frequency Handover
Availability
This feature is available from eRAN1.0.
Summary
Inter-Frequency Handover enables a UE in connected mode to be served continuously when it moves across different cells that are operating at different frequencies.
Benefits
The coverage-based inter-frequency handover provides supplementary coverage in inter-frequency LTE systems to prevent call drop, enable seamless coverage, and therefore improve the network performance and end user experience.
Description
This feature is one of the fundamental functions for an LTE system. The purpose of inter-frequency handover is to ensure that a UE in RRC-CONNECTED mode is served continuously when it moves across different cells operating at different frequencies.
The inter-frequency handover procedure can be divided into four phases:
measurement triggering, handover measurement, handover decision, and handover execution.
In inter-frequency handover, neighboring cell measurements are inter-frequency measurements. The measurement is gap assisted for UEs with one RF receiver. The measurement is triggered by an event A2 and stopped by an event A1, based on the monitoring on the value of RSRP or RSRQ.
In inter-frequency handover, the UE sends measurement reports to the eNodeB when the RSRP or RSRQ meets the criteria set in the measurement configuration.
Upon receiving a measurement report from the UE, the eNodeB makes a handover decision. If the measurement meets the handover criteria, the eNodeB will perform the corresponding inter-frequency handover as specified in TS 36.300.
The following inter-frequency handover scenarios are applicable:
Handover between two cells configured in the same eNodeB. In this case, the UE performs the handover between two cells configured in the same eNodeB and no external interface is required.
Handover between two cells configured in different eNodeBs with an X2 interface available. In this case, the source eNodeB sends a HANDOVER REQUEST message over the X2 interface.
Handover between two cells configured in different eNodeBs with no X2 interface available. In this case, the source eNodeB sends a HANDOVER REQUIRED message over the S1 interface.
Enhancement
None
Dependency
None
1.26.3 LBFD-00201803 Cell Selection and Reselection
Availability
This feature is available from eRAN1.0.
Summary
Cell selection/reselection is a mechanism for UE in idle mode to select a cell to select/reselect a cell to camp on and to receive the most appropriate service support
upon session activation in LTE systems.
Benefits
This feature provides a mechanism for UE in idle mode to select/reselect a cell to camp by supplementary coverage in LTE systems.
This feature facilitates the automatic selection of the network for UE in idle mode and avoids the complexity of manual operations.
The UE is always bound to a relatively good cell to obtain better service quality.
Description
When UE selects a PLMN or transition from RRC-CONNECTED to RRC-IDLE, cell selection is required. The Non-Access Stratum (NAS) can determine the RAT(s) in which the cell selection should be performed, for instance, by indicating the RAT(s) associated with the selected PLMN and by maintaining a list of forbidden registration areas and a list of equivalent PLMN. The UE shall select a suitable cell based on idle mode measurements and cell selection criteria.
UE in RRC_IDLE can perform cell reselection if UE find a cell with a better radio environment. When camping on a cell, UE shall regularly search for a better cell according to the cell reselection criteria. If a better cell is found, that cell is reselected.
Absolute priorities of different E-UTRAN frequencies can be provided to the UE in the system information and optionally in the RRC message releasing the RRC connection.
Enhancement
None
Dependency
None