LTE Bler Error Block rate introduction

In a wireless network, a device (such as ENODEB) sends data to another device, such as a UE, by block. The sender uses the data in the block to calculate a CRC and sends it along with the block to the receiving end. The receiving end calculates a CRC based on the received data and compares it with the received CRC, and if the two are equal, the receiving end is deemed to have successfully received the correct data and reply an "ACK" to the sender; If the two are not equal, the receiver thinks that it received the wrong data and replies to the sender with a "NACK "To require the sending of end multiplicity to pass the block. If the sender does not receive a reply from the receiving end during a particular period, the sending side assumes that the block was not reached at the receiving end and the sender automatically re-sends it. (Harq processing on MAC layer)
BLER (block error rate), which is the percentage of error blocks, is the percent of all blocks sent (only the first block is counted). In practice, the bler of a specific percentage (such as the bler of the data channel in LTE is required to be less than 10%) is not always necessary, because the wrong block can be re-transmitted and a special processing (such as a soft merge, etc.) is used to make the receiving side correctly solve the received data. When the bler needs to be measured and calculated, it can be done at the sending end because the Bler can be computed by the number of Nack received.
In LTE, the target bler of the control channel is 1%, the target of the data channel is Bler bit 10%. When the Bler is not more than 10%, the UE will escalate to enodeb the highest MCS it can decode.
LTE in the case of non-HARQ retransmission error block rate indicator is 10%, the addition of HARQ retransmission after the error frame rate (FER) is about 1%, coupled with the RLC layer after the ARQ performance increased to 10^-5 order of magnitude.

Example: Suppose that 500 blocks of data were sent, of which 499 block reply ack,1 block reply Nack, then Bler is 1/500 = 0.002 * 100% = 0.2% (as can be seen from this example, when calculating Bler, is not counted as the ack/nack of the retransmission block).