the problem occurs when the phone tries to connect to the data network. When it fails, it reboots.
Solution 1 , power off the smartphone, pull the SIM card out, put it back in, and then reset it.
Solution 2,
The first step is to boot your phone into recovery.
Now go to WIPE while in recovery mode and clear Delvik Cache.
Now restart you phone and see if it stays alright or goes back into a boot loop.
If the phone again restarts after landing on launch screen, then power off you phone.
Restart your phone into recovery again and delete all data/cache. Flash a new ROM if it is already on your SD card.
Once this is done, reboot your phone and hopefully you will be able to get rid of the boot loop problem. ( But there is no ROM available now!)
I know how to solve boot loop issues in PC based on windows system. It needs to modify the registry.
Go to HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Control > CrashControl > AutoReboot, click AutoReboot and set it to 0.
But it is said that there is no registry in Android system.
I just hope it can give you some hints.