Research On Congestion Avoidance And Communication Fault Tolerance Of Wireless Node In Wireless Network-on-Chip

With the increasing number of cores,the average packet transmission path continues to grow,NoC has higher latency,lower throughput and higher power consumption.3D NoC,optical NoC and RF NoC are constraints to the current manufacturing process.Wireless network-on-chip(WiNoC)has emerged as a promising paradigm for the multi-core interconnection.Wireless channels which act as transmission shortcuts in the WiNoC,can effectively shorten the network diameter.Wireless router,as the key nodes in the wireless network.However,the congestion problem or virtual channel fault problem can severely degrade network performance.When a fault or congestion occurs on wireless router,may cause more serious impact on communication reliability than other router in the network.In this paper,we study the congestion and fault tolerance of wireless router in WiNoC.The main work of this paper is as follows:(1)There are two kinds of congestion in wireless network,node-level congestion and link-level congestion.To alleviate those problems,a congestion-avoidance wireless router is proposed in this paper.For the node-level congestion,we design a scheme that allows wireless routers to be able to acquire congestion information of each other through broadcasting information in wireless channel.Thereby,wireless router with high congestion degree can be avoided by overladen data injection.For the link-level congestion,we design a parallel FIFO scheme that allows transmitting three data flits within a single cycle.In addition,a mathematical modeling is established to analyze the performance of parallel FIFO scheme.Experiments show that our work has a better performance in reducing the wireless network congestion and improving wireless resource utilization rate compared to the other WiNoCs.(2)When a permanent failure of the virtual channel in the router is occur,thereby affecting the operation efficiency of the wireless router and degrading the overall network performance.In order to effectively tolerate permanent failures in the wireless router,the virtual channel faults are subdivided into coarse-grained faults and fine-grained faults.Remapping mechanism is adopted when the fine-grained faults occured in the wireless interface;when the coarse-grained fault occurs,the virtual channel is directly discarded and permanent failure information is broadcast to all the nodes in the network,so that the wireless channel data packets can be rerouted to avoid the fault location.Experiments show that WiNoC under this scheme has a larger performance improvement than the traditional NoC or WiNoC.