Time-Triggered Frequency Scaling in Network-on-Chip for Safety-Relevant Embedded Systems

Networks on Chip (NoC) are used in Multiprocessor System on a Chip (MPSoC) architectures and safety-relevant systems as a communication backbone to cope with high communication traffic. Nevertheless, network interfaces and the routers within the NoC add to the power consumed by the chip. This paper presents models and algorithms for low power techniques in NoC based on dynamic frequency scaling for safety-relevant real-time systems. The novel technique is time-triggered frequency scaling to enable power and energy efficiency while preserving safety and real-time guarantees. Time-triggered Frequency Scaling (TTFS) is used in the routers where each router frequency is adjusted according to a schedule. Three techniques, namely global, cluster-based, and route-based TTFS are considered. Using the Orion 3 tool, we show that up to 59 % of the power consumed by an NoC can be saved when a route-based power saving technique is applied.