In telecommunication systems microprocessors have to handle the signalization process in ISDN networks and the data packets in GPRS mobile networks. In case of GPRS networks, encryption leads to a second passage, thus to feedback. Various scheduling disciplines are applied for overload control, prioritizing the different processes, efficient use of the caches and for ensuring performance characteristics. The aim of this project is the performance analysis of a single process under a gated round-robin discipline.
In the round-robin discipline the requests receive consecutively a fixed quantum of service in a cyclic manner. The round-robin discipline ensures that requests with small service requirements will not have to wait too long for finishing their service. As limiting case where the quanta tend to zero the processor-sharing discipline is obtained.
Founded on a new relation between the sojourn times of requests under processor sharing and FCFS (first come first served) efficient algorithms for the first two moments of the sojourn times in the system without feedback (ISDN networks) have been developed. In the system with feedback (GPRS networks) from some load upwards there occur transitions between several almost stationary states. This observation allowed a nearly complete decomposition of the state space, on which an approximation for the mean sojourn time in the system with feedback is based.
