We have some devices which are designed to use standard frequencies/protocols, such as GSM, CDMA, GPS, Wifi and Bluetooth, among others. While our focus is not thought to be used for high-profile criminals (such as organized crime) who will often use jammers, we are aware that this is, to our knowledge, the weakest link in our system. Thankfully it is a weak link that is very rarely exploited by the more common adversaries found in our adversary model, and we do not pretend to handle situations for such cases.
So, while this is not really a practical issue, as a technical person I can't wonder but think if there's any way that we could actually protect against jammers while still using common protocols.
Is there any strategy? This is not my area of expertise, so I am nearly clueless, but as far as I know, frequencies that are high enough in the spectrum are reserved for other uses, so we can't even change to them, and strategies like frequency hopping don't work with said protocols. I'm lost, to be honest.
EDIT: There were many excellent responses and I wish I could have accepted two of them. Thank you.