7.  Aymen I. Zreikat : "Performance of Queueing model of One UMTS cell with R virtual zones by the Maximum Entropy Solution", Wireless Personal Communications, Springer (USA), Vol. 39, No. 2, pp. 135-149, 2006.


UMTS stands for Universal Mobile Telecommunications System, which is one of the third generation (i.e., 3G) cellular systems, will come into full commercial phase by year 2005 and the first UMTS services are launched commercially in 2001. Therefore, the research of UMTS is an important and urgent task. In this paper, the performance of UMTS systems is studied through a queueing model which consists of one UMTS with many virtual zones to evaluate the system uplink traffic performance. The two performance measures: blocking probability and system utilization are obtained by the Maximum Entropy Principle, i.e., ME solutions for SRXR (GGeo/GGeo/1)/N queue. SRXR (GGeo/GGeo/1)/N system means that arrival time and service time are both GGeo (Generalized Geometric) distributed, each output port has a single server and the maximum capacity is N. After the theoretical analysis, the numerical results are found for the idiographic example, S8X8 (GGeo/GGeo/1)/512 queueing model. Additionally, the performance of this queueing model is discussed with the effect of the parameters Ca2 (squared coefficient of variation of the interarrival time), Cs2 (squared coefficient of variation of the service time) and the arrival rate, l.