Research On Key Technology Of Multicasting Communication Based On 3D Bufferless Network-On-Chip

With the rapid development of integrated circuit,chip design will enter from the multi-core era into many-core era.Network-on-Chip(NoC)becomes a promising interconnection architecture for many-core system due to its high bandwidth,low power comsumption,reusability and good scalability.With the enhancement of the intergration degree,area and power is a very important factor in the design of the many-core SoC.The development of NoC has provided a viable solution from the router with buffer to bufferless router and from 2D integration to 3D integration.Therefore,an efficient architecture of multicast router becomes an important research topic in NoC.Based on the 3D bufferless router,this dissertation focuses on the routing algorithm and the scheme of multicast for different 3D NoCs,the detailed evaluation and analysis are also given.The aim is to provide the technical support for future largescale 3D many core SoC.The major contributions can be summarized as follows:1.The multicast routing mechanism is applied to bufferless 3D Mesh network on chip.Based on the fixed area parptition,we proposed two multicast routing algorithms that are TBP(Two Block Partition)and FBP(Four Block Partiton)schemes in 3D Mesh network,which reduce the length of the search path to improve the performance of the multicast routing by division of the network.Morever,we evaluate the latency of the TBP multicast scheme by the analytical method.Finally,experimental results show that the TBP and FBP multicast schemes achieve high system performance compare to the baseline multicast routing algorithm.2.Due to the uneven distribution of multicast destination nodes of the TBP and FBP multicast schemes,we propose LBP(Layer Block Partition)multicast routing algorithm and RP(Recursive Partition)multicast routing algorithms.The multicast packets of the LBP scheme are replicated is based on the free port of the router and layer block partition rule when injectioning into the network from the local input port.The RP multicast schemes is based on the LBP multicast scheme when the number of multicast destinations is more than n in each layer in the LBP scheme.It dynamically subdivided the layer block and replicate packets based on the manhattan distance more than n(n is a integer,which is changed dynamically based on the size of the 3D Mesh network and the number of destinations).Compared to the baseline multicast routing scheme,LBP and RP multicast schemes increased the multicast routing adaptability and simulation results illustrate that LBP and RP schemes reduce the nework latency significasntly.3.Due to the fact that the 3D NoC-Bus network can overcome the disadvantages of a directly stacked structure,the thesis first proposes a bufferless router(DualBLESS)for the 3D NoC-Bus network.DualBLESS is a router with double ejection outputports based on a permutation network.The router can improve the throughput and reduce the average latency than the 3D baseline bufferless router.Secondly,the dissertation presents a deflection multicast routing mechanism for 3D Noc-Bus network by mapping multicast destination nodes to the layer region,then using the manhattan path-based search in the layer region and non-planar region nodes injection into the destinations via a bus broadcast directly.Simulation reveals that this multicast routing mechanism acquires high system performance than the baseline multicast routing algorithm.4.The dissertation explores the deflection multicast routing mechanism based on bufferless router for the 3D irregular network,then proposed two multicast routing schemes for the 3D irregular network: DRM-1 and DRM-2 mulitcast routing schemes.DRM-1 multicast routing mechanism adopts the manhattan path-based search for multicast routing.When it finds one of the best output port identifier is ‘0',it then chooses another direction(alternative direction)as the output.As any pair of nodes will fall into the regions in the convex contionuous area,there must be an alternative direction of the shortest path.The DRM-1 multicast routing mechanism differenct with the DRM-2 mulitcast routing mechanism decomposes the multicast packet into the unicast packets at the source node to route.Simulation results illustrate that DRM-1 mechanism can achieve low average lantency than DRM-2 mechanism.