BER vs BLER vs DBLER: Understanding Error Rate Measurements

This page explains the differences between BER, BLER, and DBLER measurements used to test GSM/GPRS/EGPRS compliant mobile devices.

BER (Bit Error Rate)

BER stands for Bit Error Rate. It’s the ratio of the number of bits received in error at the receiver to the total number of bits transmitted from the transmitter.

Formula:

BER = (Received bits in error / Total number of send bits)

A BER test provides a very accurate measure of system performance compared to BLER and DBLER tests. This is because it checks each of the bits transmitted and compares them with the received bits.

BLER (Block Error Rate)

BLER stands for Block Error Rate. It is a receiver measurement used in the conformance testing of GPRS/EGPRS mobiles. Retransmission is typically done for blocks that are received with errors.

BLER is the ratio of received erroneous blocks to the total number of data blocks transmitted. For example, in the CS4 coding scheme, 400 information bits are carried within a block. BLER simply provides a result of either “OK” or “NOT OK” for each block. It doesn’t provide any information on the number of errored bits within a data block.

DBLER (Data Block Error Rate)

DBLER stands for Data Block Error Rate.

Formula:

DBLER = (Received data blocks in error / Total number of transmitted blocks)

With a DBLER test, only the data bits are analyzed, while in a BLER test, the block header and USF flags are also analyzed. Both are almost the same test. DBLER does not take into account all the bits that resulted in a block error. These tests are performed in test mode B.