Default Value is 1%
BLER target for PDCCH outer loop link adaptation in percent.
Defines target Block Error Ratio (BLER) of PDCCH and UL HARQ response for initial downlink transmissions for >PDCCH Outer Loop Link Adaptation in percents.
If PDCCH OLLA is additionally based on PUSCH TX/DTX detection, the parameter defines target Block Error Ratio (BLER) of PDCCH and PUSCH missed detection for initial uplink transmissions for PDCCH Outer Loop Link Adaptation in percents.
I hope it may help.
All the vendors provide this functionality, Ericsson has parameters available to adjust the PDCCH Target BLER via Enhanced PDCCH Link Adaptation Feature.
Through Huawei is more flexible in may aspects.