System-level power/performance analysis of portable multimedia systems communicating over wireless channels

This paper presents a new methodology for system-level power and performance analysis of wireless multimedia systems. More precisely, we introduce an analytical approach based on concurrent processes modeled as Stochastic Automata Networks (SANs) that can be effectively used to integrate power and performance metrics in system-level design. We show that 1) under various input traces and wireless channel conditions, the average-case behavior of a multimedia system consisting of a video encoder/decoder pair is characterized by very different probability distributions and power consumption values and 2) in order to identify the best trade-off between power and performance figures, one must take into consideration the entire environment (i.e., encoder, decoder and channel) for which the system is being designed. Compared to using simulation, our analytical technique reduces the time needed to find the steady-state behavior by orders of magnitude, with some limited loss in accuracy compared to the exact solution. We illustrate the potential of our methodology using the MPEG-2 video as the driver application.