QCAT

QCAT is the offline half of the Qualcomm diagnostic workflow. You capture the log live in QXDM, then open it in QCAT to actually pick it apart — filter to the messages you care about, decode NAS and RRC payloads, follow a call through its state changes, and run the built-in analysis on a saved log file rather than fighting a live stream. When you're chasing why one call in fifty dropped, the offline approach is far saner: you can scroll, search, re-filter and line up timestamps without the event flying past.

Practically, a lot of post-drive UE-side debugging lives here, and the constraint to internalise is that QCAT only ever sees what was already recorded: it can't go back and pull a message the capture never logged. That puts the burden upstream — set your QXDM logging mask to include the layers you'll need before the drive, because the cheapest fix for a gap in the data is the one you can't apply after the fact, which means re-driving the whole route.