I think he is referring to Link Adaptation, not Location Area.
Here is the difference:
With link adaptation, the whole data block is retransmitted with a new coding scheme if decoding of the first block fails. However, with IR, if the decoding of one block of data fails, ADDITIONAL CODING DATA is transmitted and soft-combined with the earlier data. This will continue until the data is successfully decoded.
BLER is one of the paramaters used to determine which coding scheme should be used to transmit the next block of data in LA/IR. If the BLER is high, a lower coding scheme is used and vice versa.