Like I said....reception on my nexus especially today its been the worst ever. Also I was updating my tango app and the phone just shut down in the process. I had to pull the battery turn it turn on...
I think the only thing I've read that has helped with reception issues is to pull battery and sim card, leave them out for 90 seconds, re-insert and reboot phone. This forces the phone to update/check the PRL. It helps some times and some times it doesn't.
Good luck