International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 05 | May-2016 www.irjet.net p-ISSN: 2395-0072 © 2016, IRJET | Impact Factor value: 4.45 | ISO 9001:2008 Certified Journal | Page 2333 DESIGN AND IMPLEMENTATION OF 3D 4x4 MESH TYPE BUFFERLESS NOC USING X-Y ROUTING ALGORITHM SUSHMA N, NEETHU K N MTech student, VLSI and Embedded Systems, Dept of ECE, Reva Institute of Technology and Management,Karnataka, India Assistant Professor, VLSI and Embedded Systems, Dept of ECE, Reva Institute of Technology and Management,Karnataka, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - A basic 3D NOC Router has problems of deadlock and hot spot. Also it requires buffers to store packet data. In this paper we present 3D 4 *4 NOC Router which uses routing algorithm called X-Y Routing algorithm which will avoid deadlock and hot spot by using priority encoders. The 3D NOC Router designed here is also buffer less since the data is transferred at a speed of 1clock per node and does not require buffers to store data. The 3D NOC router is designed using Verilog HDL, simulated by Modelsim and prototyped by using FPGA. The simulation results show that it also improves the area utilization. Key Words: 3D NOC, X-Y Routing,deadlock,hotspot 1.INTRODUCTION Network on Chip(NOC) is a subsystem on an integrated circuit which acts as a communication interface between nodes in a System on Chip(SOC).SOC is an integrated circuit that combines all components of electronic system into one chip. Performance of a NOC depends strongly on its underlying architecture and routing techniques. Here we are building 3D NOC by using ʹD NOC’s. ʹD NOC’s are placed vertically one above another instead of placing them next to each other, thereby forming a 3D NOC. Compared to 2D NOC, 3D NOC has minimum latency, lower power consumption, better performance and increased area utilization. Due to constraints such as wire-length constraints and layout complications, the 2D NOCs have limited network structures that are possible. There are various types of 3D NOC topologies such as 3D Mesh, 3D Torus, 3D Stacking Mesh and so on. We are using a 3D 4x4 Mesh type NOC which consists of nodes and routers. Each node also has a priority encoder Fig-1: 3D 4x4 Mesh type NOC Router is the most important component for transferring data from one node to another. It is the communication backbone of a NOC system. So it should be designed with maximum efficiency. Routers are used on a network for directing the traffic from the source to the destination. It coordinates the data flow which is very crucial in communication networks. Routers are intelligent devices that receive incoming data packets, inspect their destination and figure out the best path for the data to move from source to destination. Router must be well designed to achieve high performance. The priority encoders output corresponds to the currently active input which has the highest priority. So when an input with a higher priority is present, all other inputs with a lower priority will be ignored. 1.1 RELATED WORK Different types of routing algorithms have been mentioned by other papers Paper [1] shows a router which uses a Elevator-first routing algorithm which transmits packets to the destination node in an irregular topological structure. But this algorithm suffers from deadlock. Paper [2] shows a router which uses look ahead XYZ routing algorithm, which reduces the power consumption but it occupies significant area since it uses input buffer. So it is not buffer less. Paper [3] addressed the thermal power problem in 3D NOC’s which is one of the most important issues in ͵D NOC’s. The routing algorithms which are used takes too many