Modeling and performance analysis of resource allocation strategies for real-time services in UMTS using TIPPtool

The third generation UMTS system will be able to offer a wide variety of multimedia services (speech, teleconferencing, browsing on the net, etc.). In order to allocate resources to these heterogeneous traffic sources in an efficient way, shared channels have been introduced in addition to the traditional transfer on dedicated channels. Although initially conceived for not real-time packet users, shared channels can satisfy the performance requirements of real-time traffic, thanks to the short and efficient channel reservation signaling phase. This paper compares the performance of the radio resource allocation strategies based on dedicated and shared channels, and quantifies the increase in system capacity of an hybrid solution, where shared channels are used to convey the bursty low priority component of a real-time video service. Since the low priority packets that cannot be delivered are dropped, a specific minimum amount of shared resources is required to match the global quality of service requirements of the video service. ng and numerical analysis are carried out with the TIPPtool package. With its formal and effective notation and the provision of stochastic features, a compact system specification can be obtained and validated for proper behavior, and performance measures can be derived. In order to numerically evaluate the huge state-space of the complex system under study, a compositional approach is proposed: the system is decomposed into simpler components, which are analyzed separately and whose numerical results are associated for global performance evaluation.