But if your RBLER is not zero it means you also have drops because not all RRC messages will pass in Downlink.
Name of param is DlHarqMaxTxNum
Indicates the maximum number of downlink hybrid automatic repeat request (HARQ) transmissions. For details, see 3GPP TS 36.331. This parameter applies only to LTE FDD and LTE TDD.
Possible values 1 to 6.
Make it 6.
This will reduce your RBLER but will not make it zero.
try this switch, it will improve both UL/DL RBLER, it improves the condition of the UE in cell border with weekcoverage :
Termination of the downlink scheduling of UEs in extremely weak coverage areas or with radio link failures prevents these UEs from overusing system resources. If the AbnUeSchSwitch option of the CellAlgoSwitch.CellSchStrategySwitchparameter is selected, the downlink scheduler evaluates link faults based on the HARQ feedback transmitted on the PUCCH of format 1a, 1b, or 1bcs in response to downlink transmission. If the HARQ feedback indicates a consecutive number of DTXs that exceeds the value of the CellDlschAlgo.DlSchAbnUeThdparameter, the downlink scheduler determines that the UE has encountered a link fault. The scheduler then stops downlink scheduling for initial transmissions and retransmissions to the UE. If the UE is working in the carrier aggregation(CA) state, this function takes effect in the primary serving cell (P Cell) of the UE but does not take effect in any secondary serving cell (S Cell).