The PS3 does not support pausing and resuming downloads. Once started, a download must finish or be cancelled (restarting from 0%). This was a firmware limitation never patched.
Workarounds
Wired Ethernet: Eliminates Wi-Fi drops — #1 cause of failed downloads.
Download overnight / off-peak: Less network congestion, lower chance of ISP throttling.
Background download (auto-shutdown): Settings → Power Save → “Background Download” + “Auto-Shutdown after download”. Starts download in standby; console powers off when done.
PSN Store on PC/Phone → “Download to PS3”: Purchase remotely; PS3 wakes (if in standby) and downloads. Still no pause.
Large files (>2GB): Highest failure risk. Consider downloading on PC via PS3 Proxy / PKG Link (custom firmware required) then transferring via USB — advanced, CFW only.
Comparison
PS4/PS5: Full pause/resume, rest mode download, segmented downloading.
PS3: Monolithic, fragile, no resume.
Plan around it: wire it, start before bed, don’t interrupt.