The introduction presentation to GSM networks gave a good overview of what the GSM network was about. Even though I have been using mobile phones well over a decade, I have not really gotten around to find out what was really happening behind the scenes. It was easy to follow the overall picture but the specificity of some of the topics ( like how the BTS and the BSC work) would take a bit more of reading for a clearer understanding. These are a few of the things that I found interesting in the cell phone realm. Though it may not be specific to GSM, I thought I should mention. Closed user group (CUG): It was a feature that was given out by the service provider since 2005 especially to corporate clients where all the calls made within the group was free. This was a big deal back in the day, as maintaining a cell phone was an expensive affair. I am curious how they made this profitable then.
Prepaid Mobile Service: Pre-paid mobile service, is perhaps the movement that made cell phones popular and affordable in India.
Missed call: This is an interesting phenomenon that is used in developing countries even today to communicate just by calling and hanging up, to communicate pre-agreed messages for free. This is supposedly causing huge revenue losses to the carriers. It would be interesting to find out what exactly happens when a call is made, to understand the network usage a little better.