BLER in LTE

The Block Error Rate (BLER) is a measure of how successful a data transmission is over the air at the Physical/MA layer level! "f a trans#ort $lock is successful decoded (the R calculated  $y the receiver matches the R sent in the $lock% then the transmission is successful! successful! The tar&et BLER for the radio link is ty#ically set to ' (meanin& that the transmission must $e sent in such a way as to achieve a * success rate on avera&e)! "f the transmission fails% then the receiver indicates this with a +AR, -A. (ne&ative acknowled&ement) the sender can then send additional information (e!&! error correction $its) to hel# the receiver decode the ori&inal transmission (a so0called +AR, retransmission)! The receiver com$ines the new $its with the ori&inal $its% and tries to decode the $lock a&ain if successful% the transmission is com#lete% if not% another +AR, retransmission can #rovide more hel#! 1enerally s#eakin&% +AR, will try 2 times to & et the $lock throu&h (ori&inal 3 4 retransmissions)% after which the transmission is considered to have failed! 25!24' 6ections 7!4 and 7!2 #rovide the details on +AR,! At the Physical Layer for LTE% LTE% the tar&et error rate is ' in 8MT6% the tar&et could $e confi&ured% and was often set to ' '  or 4! 9ou 9ou can read more a$out +AR, in 25!24'% sections 7!2 and 7!:! 8#link ada#tation is really u# to the e-B e -B vendor! 8sin& the availa$le fee$ack from u#link transmissions (such as ;MR6% 6R6 and +AR, stats)% the e-B can ad