Explorations of Honeycomb Topologies for Network-on-Chip

Rectangular mesh and torus are the mostly used topologies in network-on-chip (NoC) based systems. In this paper, we quantitatively illustrate that the honeycomb topology is an advantageous design alternative in terms of network cost which is one of the most important parameters that reflects both network performance and implementation cost. Comparing with the rectangular mesh and torus, honeycomb mesh and torus topologies lead to 40% decrease of the network cost. Then we explore the NoC related topological properties of both honeycomb mesh and torus topologies. By transforming the honeycomb topologies into rectangular brick shapes, we demonstrate that the honeycomb topologies are feasible to be implemented with rectangular devices. We also propose a 3D honeycomb topology since 3D IC has become an emerging and promising technique. Another contribution of this paper is the proposal of deadlock free routing algorithms. Based on either the concept of turn model or the logical network, deadlock free routing for all the discussed honeycomb topologies can be achieved.