PHiCIT — Improving hierarchical Networks-on-Chip through 3D silicon photonics integration

The Network-on-Chip (NoC) architecture has been seen as an interconnect solution for complex systems. However, performance and energy issues still represent limiting factors for Multi-Processors Systems-on-Chip (MPSoC). In order to match low power and high performance, hierarchical NoCs have been proposed, with interconnecting clusters of IPs tailored to application specific domains. In the near future however, this methodology will be limited by the long wires for global connection. In this paper, we present an optimized hierarchical network-on-chip, the PHiCIT (Photonic Hierarchical Crossbar-based Interconnection Three-dimensional architecture). This architecture proposal aims to maximize the overall performance by using three levels of interconnection: photonic crossbars for intra-cluster communication, traditional electric routers for the inter-cluster communication, and 3D technology to explore power and area optimization. Experimental results show that PHiCIT can reduce the latency against a pure electrical mesh NoC by up to 47%, against an electric hierarchical NoC by up to 6%, and against a photonic mesh NoC by up to 34%, considering PARSEC benchmark applications.