Global System for Mobile communication (GSM) is a widely accepted standard for digital cellular communication. It has become the mobile communication standard in more than 160 countries all over the globe. In this paper, we are interested in modelin
“The 3G IP Multimedia Subsystem (IMS): Merging the Internet and the Celluar Worlds” by Gonzalo Camarillo, Miguel-Angel Garcia-Martin, John Wiley & Sons, 2006