In LTE networks, handover procedures are critical for maintaining seamless connectivity and quality of service (QoS) as a User Equipment (UE) moves from one cell to another. Various LTE parameters influence the handover decision and execution processes.
Here are some common handover-related parameters in LTE:
1. Cell-Specific RS Power.
Basic Information:
| Parameter Name | Value Range | Physical unit | Step |
| Cell-specific reference signals power | -60~50 | dBm | 0.1 |
| Default | Transfer Path | Action area | Derived from |
| 9 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Serving Cell Configuration>>Base Information>>Cell-specific reference signals power | |||
This parameter indicates the power of the cell-specific reference signals. It is an absolute value.
The cell-specific reference signal is used for cell search, downlink channel estimation, and channel detection, which has an immediate influence on the cell coverage. This signal notifies the UE by means of SIB2 broadcast and it remains constant in the overall downlink system bandwidth and all sub-frames, unless there is some changes in the SIB2 message, such as RS power enhancement.
Impact of Parameter Adjustment.
The power setting of downlink channel is based on the reference signal power; therefore setting or changing reference signal will affect the setting of the entire downlink power setting. Too large RSRP will lead to pilot pollution and inter-cell interference, whereas too small will result in cell unable to be selected or reselected as well as data channel incapable of being demodulated.
2. Offset Between PDSCH EPRE and Cell-Specific RS EPRE (P_A_DTCH) of Center Users.
This parameter indicates the ratio between the data RE (OFDM symbol of pilot excluded) power and the pilot RE power of a UE.
Basic Information.
| Parameter Name | Value Range | Physical unit | Step |
| The Offset Between PDSCH EPRE and Cell-specific RS EPRE (P_A_DTCH) of center user | -6, -4.77, -3, -1.77, 0, 1, 2, 3 | dB | |
| Default | Transfer Path | Action area | Derived from |
| -3 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Serving Cell Configuration >>MAC ALG C >>The offset Between PDSCH EPRE and Cell-specific RS EPRE(P_A_DTCH) of centre user | |||
3. Minimum Reception Level Needed for Cell Selection.
Qrxlevmin indicates the minimum reception level needed for cell selection and reselection. The cell selection condition will be met only when the reception level of the tested cell is greater than the Qrxlevmin.
| Parameter Name | Value Range | Physical unit | Step |
| Sel_Qrxlevmin | -140~-44 | dBm | 2 |
| Default | Transfer Path | Action area | Derived from |
| -130dBm | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Serving Cell Configuration >>Cell Selection and Reselection >>Sel_Qrxlevmin | |||
Impact of Parameter Adjustment.
Setting or changing this parameter has an impact on the range of cell downlink coverage.
4. Filter Coefficient for RSRP.
The RSRP measuring result reported on the physical layer needs passing layer-3 filter to eliminate jitter. The results used by RRC all must go through the layer-3 filter. The filter formula is:
Fn is the filter measuring result after updated. Fn-1 is the old filter measuring result. Mn is the latest received measuring result from physical layer. K in the above formula is the Layer-3 filter coefficient.
| Parameter Name | Value Range | Physical unit | Step |
| Filter Coefficient for RSRP | 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19 | ||
| Default | Transfer Path | Action area | Derived from |
| 13 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Serving Cell Configuration >>Parameters of Measurement Configuration >> Filter Coefficient for RSRP | |||
5. Event Identity.
This parameter indicates the event identify triggered by intra-frequency measurement. It is related with measured value.
| Parameter Name | Value Range | Physical unit | Step |
| Event Identity | A1, A2, A3,A4,A5 | ||
| Default | Transfer Path | Action area | Derived from |
| Event report parameters for measured value being RSRP: A1, A2, A3,A4,A5; Cycle report parameter for measured value being RSRP:- Event report parameter for measured value being RSRQ: A1, A2, A3,A4,A5 Cycle report parameter for measured value being RSRQ: – | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Event Identity | |||
6. Cell individual offset.
Each monitored cell is assigned with an offset which can be positive or negative with the in-band signaling. Before evaluating whether an event has taken place at the UE, the offset should be added into the measured value, thus to affect the condition of triggering the measurement report.
| Parameter Name | Value Range | Physical unit | Step |
| Cell individual offset | -24 to 24 | dB | 1 |
| Default | Transfer Path | Action area | Derived from |
| 0 | ENB->UE | CELL | 3GPP |
| Configure path | |||
| OMCR Setting Screen:Serving Cell Configuration >>ENodeB Neighbouring Relation >> Cell individual offset | |||
Impact of Parameter Adjustment.
When set the offset as a positive value, it is easy to hand over to this cell. When set as a negative value, it is difficult to hand over to this cell.
7. Time to Trigger.
Time to Trigger is the time difference from the time when an event is detected to the time when this event is reported. Only when an event is detected and it always meets the event trigger condition during this Time to Trigger, the event will be triggered and reported.
Higher Time to Trigger represents stricter triggering to event. The length of this time should be configured according to actual situation, because sometimes too long Time to Trigger will affect the communication quality of user.
| Parameter Name | Value Range | Physical unit | Step |
| Time to Trigger | 0, 40, 64, 80, 100, 128, 160, 256, 320, 480, 512, 640, 1024, 1280, 2560, 5120 | ms | |
| Default | Transfer Path | Action area | Derived from |
| 256 | ENB->UE | eNb | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Time to Trigger | |||
8. Hysteresis.
This is the hysteresis range when making decision.
| Parameter Name | Value Range | Physical unit | Step |
| Hysteresis | 0, …, 15 | dB | 0.5 |
| Default | Transfer Path | Action area | Derived from |
| 256 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Hysteresis | |||
9. Amount of Reporting for Event.
This parameter indicates the maximum amount of reporting the measurement report after an event is triggered. After an event is triggered, the UE reports the measuring result by the reporting interval. When the amount of reporting exceeds this value, it will stop reporting measuring result.
| Parameter Name | Value Range | Physical unit | Step |
| Amount of Reporting for event | 1, 2, 4, 8, 16, 32, 64, Infinity | ||
| Default | Transfer Path | Action area | Derived from |
| infinity | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Amount of Reporting for event | |||
10. Reporting Interval for Event.
This parameter indicates the reporting interval for periodical report in the periodical report rule.
| Parameter Name | Value Range | Physical unit | Step |
| Reporting Interval for Periodical | 120, 240, 480, 640, 1024, 2048, 5120, 10240, 60000, 360000, 720000, 1800000, 3600000 | ms | |
| Default | Transfer Path | Action area | Derived from |
| 1024 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen:Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Reporting Interval for Periodical | |||
11. Maximum Cell Number Reported.
The parameter indicates the maximum cell number reported.
| Parameter Name | Value Range | Physical unit | Step |
| Maximum Cell Number reported | 1, 2, …, 8 | ||
| Default | Transfer Path | Action area | Derived from |
| 8 | ENB->UE | Cell | 3GPP |
| Configure path | |||
| OMCR Setting Screen: Base Station Radio Resource Management>>Measurement Configuration >>IntraFreq Measurement for Handover>> Maximum Cell Number reported | |||
Read Also:
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What is S1 Handover in LTE?