Block Error Ratio Troubleshooting

Possible Setup Issues

• When performing the block error ratio measurement for Symmetrical RMCs :
  • The UE must be configured in loopback mode 2 (see UE Loopback Type ).
  • Uplink DTCH RMC CRC Presence must be set to Used for Data .
• When using FDD Test Operating Mode , you must manually configure the UE during testing; no overhead messaging or signaling is provided to set up the mobile station in this operating mode. See UE Control During FDD Test Mode Operation .
• For Asymmetrical RMCs , the test set will stop sending downlink transport blocks to the UE if it does not receive an acknowledgment or retransmission request from the UE for a significant period of time. If the UE does not then drop the call, the measurement will hang. You must increase the downlink signal-to-noise ratio (e.g. increase Cell Power or decrease AWGN Power so that the UE can detect the downlink transport blocks and send acknowledgments or retransmission requests to the test set). You must also disconnect and then reconnect the call, then re-initiate the measurement. To prevent the measurement from hanging again in the future, enable the Measurement Timeout . Note, however, that before re-initiating the measurement you will still need to increase the downlink signal-to-noise ratio, then disconnect and reconnect the call.
• During remote operation of the block error ratio measurement, you should configure the trigger arm to single. See SETup:WBLerror and Triggering of Measurements .
• During front panel operation of this measurement, if Trigger Arm is set to Single (see Trigger Arm (Single or Continuous) Description ), you must press the START SINGLE key to initiate the measurement.
• Measurement results are influenced by any amplitude offsets that are entered, since the level into the UE is altered.

Interpreting Integrity Indicator Values

• If Measurement Timeout (2) is returned:
  • The Measurement Timeout value you entered for the measurement may be too small for the Number of Blocks to Test . In this case, either reduce the number of blocks to test or increase the timeout value.
• Questionable MS-to-Cell Data (28) is returned if a missing block is detected (see Uplink Missing Blocks ).

Other Considerations

• The block error ratio and loopback bit error ratio measurements can not be run concurrently. If a BLER measurement is initiated while a BER measurement is active, the BER measurement is aborted and the measurement is closed (and vice versa).

• It is not necessary to synchronize the test set and UE when performing the block error ratio measurement (it is not necessary to align received uplink transport blocks with their corresponding downlink transport blocks), whereas the test set must align the uplink and downlink blocks before performing the loopback BER measurement. Thus, the measurement does not determine the UE's Loopback Delay , whereas the loopback BER measurement does.
• To perform the block error ratio measurement for symmetrical RMCs, Uplink DTCH RMC CRC Presence must be set to Used for Data . This disables the uplink CRC. Thus, the block error ratio measurement does not report any uplink CRC Errors , whereas the loopback BER measurement does. Thus, it is very important that you ensure the uplink is robust (error free).
• The Uplink Missing Blocks result does not apply to Asymmetrical RMCs .

Related Topics

Integrity Indicator

+200 through +299 Error Message Descriptions

Block Error Ratio (BLER) Measurement Description