Last updated: 2010-03-10
Block Error Ratio Measurement Description
Block Error Ratio Measurement Parameters
Block Error Ratio Measurement Results
3GPP TS 34.122, F.6.1.1 defines block error ratio (BLER) as follows: "A Block Error Ratio is defined as the ratio of the number of erroneous blocks received to the total number of blocks sent. An erroneous block is defined as a Transport Block, the cyclic redundancy check (CRC) of which is wrong."
To perform a block error ratio measurement, you must be on a Radio Bearer Test Mode call. The following test senarios are provided depending on UE Loopback Type:
When the UE is operating in Type 1, RLC AM loopback type, the block error ratio is calculated by the ratio of number of UE retransmission requests and the total number of blocks sent to the UE. In AM the UE indicates missing protocol units (=transport blocks) in the STATUS PDU message.
When the UE is operating in test loop mode 2, the block error ratio is calculated by checking returned data and CRC and count number of block errors and the total number of sent blocks.
The BLER measurement is only available when the following conditions are met:
Operating Mode is Active Cell;
UE Loopback Scenario is either Type 1, RLC AM or Type 2;
if the call status is Connected, the current service type is RB Test Mode or, if the call status is Idle, the Paging Service Type is set to RB Test Mode;
the Channel Type is 12.2k RMC.
Number of Blocks to Test - Sets the number of blocks to test during the measurement.
Note, the time for the measurement to complete increases linearly with the Number of Blocks to Test . For example, to test 500 blocks while on a 12.2k RMC takes approximately 10 seconds (500 blocks x 20 ms/block = 10 seconds).
GPIB Command: SETup:TBLerror:COUNt
Trigger Arm - see Trigger Arm.
Measurement Timeout
See Measurement Timeout. Ensure that the Measurement Timeout is greater than the time the measurement needs to measure the desired Number of Blocks to Test .
Integrity Indicator: see Integrity Indicator.
Block Error Ratio
The ratio of incorrectly received blocks to the total blocks sent to the UE, expressed as a percentage (%). GPIB Command: FETCh:TBLerror:RATio?
Block Error Count
The number of incorrectly received blocks, or "block errors". GPIB Command: FETCh:TBLerror:COUNt?
Blocks Tested
Number of blocks tested to determine the Block Error Ratio and Block Error Count results. GPIB Command: FETCh:TBLerror:BLOCks?
Uplink Missing Blocks
The UE sends a TFCI for each uplink DTCH transport block. When operating in Active Cell Operating Mode, the test set monitors the uplink TFCI, and can report uplink missing blocks. If the TFCI indicates that there is no data block sent for that TTI, the test set reports a missing block. When an uplink missing block occurs, no block comparison is done on the block, and the number of Blocks Tested is not incremented. GPIB Command: FETCh:TBLerror:MBLocks?
GPIB Commands: SETup:TBLError, FETCh:TBLerror