Signaling capacity in GSM & (E)GPRS networks

Due to the introduction of new packet switched services as GPRS and EGPRS in the existing GSM networks, the effects on these networks need to be analysed. We address the effect of (E)GPRS services in the signaling capacity of GSM networks. The standards allow one to have separated pools for traffic channels, in order to make the resources for voice calls and data services independent. Nevertheless, the channels used for signaling purposes can be either the same for both services or different. These channels are the common control channel (CCCH) and packet common control channel (PCCCH). CCCH is used in GSM networks for call establishments and other signaling procedures, and it can also be used for (E)GPRS. PCCCH is an independent channel used only for (E)GPRS, which makes it impossible to degrade GSM calls due to signaling, and also, it presents other advantages, i.e. having different frequency lists and cell reselection criteria from the GSM ones, or allowing one to chose the cells that can be selected for each service. This paper presents a study about the signaling capacity for both options. By means of simulations, first the capacity of CCCH for GSM networks is analysed considering all the needed signaling between the mobile and base station. Then, the remaining resources of the CCCH channel are calculated in order to find out the capacity that can be used for (E)GPRS services. The capacity of the PCCCH is also simulated in order to compare its signaling capacity with CCCH.