Performance analysis of reservation media-access protocol with access and serving queues under bursty traffic in GPRS/EGPRS

Performance modeling of the contention-based reservation protocol in GPRS/EGPRS under bursty traffic is practically useful in system design. Instead of using discrete event simulation, in this paper we construct an analytical model based on stochastic Petri net formalism to efficiently investigate GPRS uplink performance. The model is built to capture the major features of a realistic system, taking into account factors such as the traffic profile, the system’s capture capability, the contention persistence, the multi-slot capability, and the use of access queue (AQ) and the round-robin virtual serving queue (SQ). As shown in numerical results, these factors have different impacts on the performance measures, such as link control layer frame blocking probability, frame delay, system throughput and packet channel utilization. To avoid modeling and computational complexity in modeling a GPRS/EGPRS system supporting a fair number of mobile terminals, we make first-order approximations and use an iterative fixed point scheme. Comparisons with discrete event simulations are conducted and show promising agreement with the proposed analytical-numerical model. We then use the model to investigate GPRS packet data performance under different parameter settings and present numerical results, which provide insights into network design and optimization.