Basic Research And Design Of Topology In Network On Chip

As an improvement on SoC(System-on-Chip), NoC(Network-on-Chip) is an inter-communication-based network system, which is realized on an integrated circuit. With theincrease of the circuit integration, SoC based on the bus architecture has been unable tosatisfy the increasing requirement of network communication. The shortcomings of SoC havebeen exposed gradually. At this time, NoC was proposed. It transplants network technologyfrom computer system and replaces the bus structure with network structure. In this structure,computing and communication are separated. Due to the solution of the bottleneck of SoCsystem in architecture, NoC is rather promising.NoC is mainly characterized by three factors, the network topology, routing algorithmand switch technique. They determine the layout of the nodes and lines in the network and theway which is used to communicate. After researching the main technology of NoC, this paperproposes a new topology. Our main work is as follows:1) Based on the study of topology, routing algorithm and switch technique, we proposea new topology——MI-Mesh by improving2D Mesh topology. As the outstanding propertyof this topology, an end node connects with more than one routers, which makes the topologyhas a higher connectivity. The topology exhibits a smaller diameter compared with2D Mesh,provides a high degree of fault tolerance. Another, collective communication can beefficiently implemented in the topology.2) To be aimed at the characteristic of connection, we propose a routing algorithmSPF(Shortest Path First) based on XY routing. SPF tries to choose the shortest path fromsource to destination. If the path blocks up, it will try other path according to the connectivityof the network. Further, an adaptive SPF algorithm is introduced aim at the shortage of theSPF algorithm.3) Combining with power gating technology, we realize a low power design based onadaptive SPF which switches off unused ports and switches in a proper time. At last, weevaluate the performance of proposed network with two algorithms and compare with2DMesh topology in accepted traffic and power consumption. The results show improvedstructure performs better that2D Mesh in accepted traffic. On the other side, powerconsumption of the system decreases obviously under low traffic if using low power design.