A Dual-Port Access Structure of 3D Mesh-Based NoC

Abstract

Since the length of wires between different layers, even between the top and bottom layers, is acceptably small in 3D mesh-based NoC (three-Dimensional mesh-based Network on Chip), a structure in which an IP (Intelligence Property) core in a certain layer directly connected to a proper router in another layer may efficiently decrease the average latency of messages and increase the maximum throughput. With this idea, in the paper, we introduce a dual-port access structure, in which each IP core except that in the bottom layer is connected to two routers in two adjacent layers, and, in particular, the IP core in the bottom layer can be directly connected to the proper router in the top layer. Furthermore, we derive the close form expression of the average number of hops of messages and also give the quantitative analysis of the performance when the dual-port access structure is used. All the analytical results reveal that the average number of hops is reduced and the system performance is improved, including a decrease of average latency and an increase of maximum throughput. Finally, the simulation results confirm our theoretical analysis and show the advantage of the proposed dual-port access structure with a relatively small increment of area overhead.