4G Important QXDM Log | QXDM Tool


QXDM Tool is most widely used tool in wireless 4G,5G technology to capture Qualcomm based Mobile signalling and data details logs for debugging purpose. Whether it is Field testing or Lab testing, initial product development or carrier acceptance QXDM is most accepted tool.

In this post, we tried to put some of very import Logs packets information to help Wireless Test Engineers, how they can make best use of QXDM to debug any issue.

QXDM Packets Details

Initial Access Logs Packets

Initial Access logs are related to cell search procedure, it shows results related PSS, SSS and frequency scan to get Physical Cell ID (PCI).

QXDM Logs for PSS decode results Frequency and Bandwidth scan results from QXDM Initial Cell Selection results from QXDM logs

System Information Block (SIB) Decode 

SIB is transmitted over the PDSCH channel and scrambled with SI-RNTI. Below logs show that Successful and Failure decode of SI-RNTI Data

  • System Information Block #1

  • System Information Block 2  or SIB 2 content channel access information for Uplink


Signaling Radio Bearer Configurations (SRBs) QXDM Logs



Signaling Radio Bearer 2 configuration

Radio Link Monitoring (RLM)

Scheduling Request (SR) QXDM Logs

SR plays very important role for Uplink performance in 4G wireless system. Poor SR performance can lead to RLF issues.

Control Information (CQI/RI/PMI/HARQ) for Uplink over PUCCH:

PUCCH is uplink control channel carries CQI, Rank Information, PMI and HARQ ACK/NACK feedback. These log packets are very useful for debugging throughput issues.

Buffer Status Report (BSR) and Power Head Room (PHR):

BSR and PHR logs are very useful for MAC layer debugging in 4G LTE.

Measurements Serving and Neighbors QXDM Logs:

Neighbor measurement are useful for Handover and Cell Selection/reselection procedure validation.

Serving Cell Measurement for RSRP

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