Performance analysis of high speed circuit switched data (HSCSD) over GSM

The paper presents a nonpreemptive priority queueing system model for voice and HSCSD service integration in GSM. The study is conducted using a multidimensional Markov chain. An HSCSD connection can be established if the number of available channels is between a minimum acceptable capacity, b, and a maximum required capacity, B. This leads to an effective service time for HSCSD calls, proportional to the bandwidth negotiated with the base station. Finite buffers are used for new and handoff requests to increase the total carried traffic, while maintaining the quality-of-service (QoS) requirements. The analysis can be applied when mean service times for voice and HSCSD calls are different. The key parameters which control the new data service performance are identified and adequate formulas are obtained. Especially, delays experienced by HSCSD calls are evaluated and compared to an optimal transmission operating at the maximum capacity.