Similar post: http://forum.mikrotik.com/t/lhg-4g-kit-unstable-lte-connection/134814/1
My answer:
*) read wiki about LTE
*) send logs to remote syslog/linux
*) save logs to action=disk to check it after reboot.
*) watchdog create a suport.rif? You can read this file at mikrotik.com account and check latest logs!.
*) You can swap sim port to down/b and again to restore to up/a
*) You can grab lte info and send SMS when LHG is offline.
*) You can create own script action when you receive a specific SMS like reboot, 2xchange sim slot, disable/enable lte etc.
I hope I give you some ideas.