Protector: A Permanent Fault Resilient Router Architecture for Network on Chip

The decreasing size of the transistor has increased the vulnerability towards faults. Increasing number of cores on a single chip has made the concept of Network on Chip (NoC) a standard communication backbone among cores. This facility comes with vulnerability of faults in the system due to decreasing size of transistors. A permanent fault in the network leads to undesirable consequence such as permanent blocking of flits or failure of the whole router. Preserving the router in the operational state has a significant impact on the reliability of the system. Permanent fault in buffers and pipeline stages of the router has a high impact on performance. The proposed router architecture Protector provides faults protection to both buffers and pipelines stages by exploiting the concepts of borrowing from other resources, using bypass paths and by creating multiple paths to reach output. The proposed router incurred an area overhead of 30% as compared to the baseline design. Reliability analysis using Silicon Protection Factor indicates that the proposed router has better fault tolerance efficiency as compared to state of the art. Latency analysis using PARSEC and SPLASH-2 benchmarks indicates proposed router incurs 13% and 16% latency overhead in the presence of faults.

A Study on Application of Recloser Operation Algorithm for Mixed Transmission System Based on Travelling Wave Method

Recently, the operation of a mixed transmission system has increased due to rapid urbanization and the purpose of a good view. Therefore, a proper protection scheme for a mixed transmission system is required. Generally, when a fault occurs on a transmission line, auto reclosing is performed for the purpose of improving the continuity of service by clearing the fault and restoring the power system. However, the auto reclosing scheme should be applied to a mixed transmission system carefully because the mixed transmission system involves underground cable sections. When a fault occurs in the underground cable section, it is mostly a permanent fault. If auto reclosing is performed on a permanent fault condition, it may cause excessive overcurrent and switching surge, which can generate a serious impact on the whole transmission system and even cause an explosion. Due to this, many utilities worldwide do not allow auto reclosing or only apply it very restrictively on a mixed transmission system based on their practice. However, there is no clear guidance or standard related to auto reclosing on a mixed transmission system. Therefore, in this paper, an application of a recloser operation algorithm is proposed. Based on the proposed algorithm, reclosers can work properly and protect the transmission system. To verify the proposed algorithm, simulations were conducted using the ElectroMagnetic Transient Program (EMTP).

Design of a Wireless Router with Virtual Channel Fault Tolerant in WiNoC

Due to chip manufacturing process defects and other factors, the virtual channel permanent fault may occur at the wireless interface in the WiNoC. This fault will affect the operating efficiency of the wireless router and degrade the network performance of the chip. In order to effectively tolerate permanent faults in virtual channels, faults are subdivided into coarse-grained and fine-grained faults. When a fine-grained fault of the virtual channel occurs at the wireless interface, the remapping mechanism is used to tolerate it; when a coarse-grained fault occurs, this unavailable virtual channel is directly abandoned and permanent fault information is broadcast to all nodes in the network. Packets that require a wireless channel can be routed to avoid passing through the fault wireless router. This method can effectively reduce the routing delay caused by the permanent fault of the virtual channel at the wireless interface. Experiments show that compared with the traditional WiNoC and other WiNoC fault-tolerant schemes, the fault-tolerant scheme proposed in this paper has a great improvement in performance and the advantages of low overhead and good scalability.