Performance analysis of GSM traffic channel capacity with(out) high speed circuit switched data

Analytical techniques for GSM traffic channel capacity analysis are studied. The results are represented for high speed circuit-switched data (HSCSD) traffic channels co-existing with voice traffic channels in a GSM cell. In a GSM system the base station has a finite number of traffic channels, from which one voice terminal occupies one traffic channel. The admission priority for voice services is higher than that of the HSCSD data. On the other hand, one HSCSD terminal can occupy a multiple number of channels if needed, provided that they are available. The HSCSD terminal will release its reserved traffic channels only after the data transmission is completed. The presence of HSCSD services slightly increases the blocking probability of the voice terminals. The results in this paper show the steady-state channel utilization and blocking probability of voice terminals under the constraints where voice terminals occupy one traffic channel at a time and data terminals can occupy multiple number of traffic channels. The results show that for a defined acceptable voice blocking probability, the overall channel utilization increases with the higher number of HSCSD terminals allowed per base station as well as with the higher number of channels allowed to be allocated for each HSCSD terminal. The traffic channel utilization also increases if the acceptable blocking probability for voice terminals is allowed to increase. The analytical model represented herein is general. Therefore, the channel utilization and the voice blocking probability results are calculated both with/without the HSCSD traffic channels. These numerical cases can be obtained by appropriate parameter setting from the same process model.