Analysis of GSM HSCSD service with channel allocation constraints

A mathematical model for analyzing the new GSM HSCSD service specified by the European Telecommunications Standards Institute (ETSI) as a part of the GSM phase 2+ standard is presented. The study is conducted using a multidimensional Markov chain for a system carrying both HSCSD and the pre existing voice traffic. The key parameters which control the new data service performance are identified and adequate formulas obtained. Delays experienced by HSCSD calls are evaluated and compared to an optimal transmission operating at the maximum capacity. The model takes into account the channel allocation constraints for HSCSD connections and their impact on system performance is investigated by comparing results with an ideal unconstrained system. The analysis is applicable when mean service times for voice and HSCSD calls are different.