Incoming & outgoing GSM signals

Hi friends,
I require a bit of help from you people. I want to know that when we have incoming & outgoing calls or sms in GSM,,a sort of signals are transmitted or received,what are those signals? Please help me if you have any related document or waveforms plz share with me.

THANKS

http://www.geocities.com/rahulscdmap...rces/GSM_I.ppt

do you mean (for example ) the call setup process, location update, or the handover?

Surely call setup,holding and location update.
The signals which usually can be detected by any passive circuit, I want to know about these.