Modem doesn't re register with network automatically

The modem EM7455 doesn’t re register with the network automatically.
I have to force the modem to register to network, implies have to reset. How would I tell the modem
via chat scripts to register to network automatically next time whenever there was a signal failure or de registered due to low signal.

I don’t think you can do it in chat script

You can write a script:
if it cannot ping google → kill the pppd → send AT!RESET → start the pppd again