Hot Carrier Injection (HCI) Tolerant NoC Router Microarchitecture

Developed by Dean M. Ancajas, James M. Nickerson, Dr. Koushik Chakraborty, and Dr. Sanghamitra Roy of Utah State University’s Electrical and Computer Engineering Department


Technical Summary

The trend towards massive parallel computing has necessitated the need for an On-Chip communication framework that can scale well with the increasing number of cores. At the same time, technology scaling has made transistors susceptible to a multitude of aging mechanisms, including Hot Carrier Injection (HCI), which plays a major role in degrading performance characteristics of NoCs over time. Such a performance degradation can have a massive system level impact in NoCs and ultimately shorten the chip lifetime.


Due to the data communication patterns in many-core applications, the inventors discovered that a majority of gate-level switching activities are restricted to a relatively small portion of the crossbar circuit gates, resulting in a large HCI degradation. To reduce HCI aging in the crossbar, patent pending “HCI-Tolerant NoC Router Microarchitecture,” provides a series of low overhead techniques that evenly distribute the switching activity without affecting latency and bandwidth of the NoC. By balancing the switching activity, these techniques substantially increase the lifetime of the NoC.


Competitive Advantages

Compared to a NoC without any reliability techniques, the best schemes improve, on average, the switching activity distribution by 19 percent, clock cycle degradation by 26 percent, system performance by 11 percent, and energy delay product per flit by 17 percent.


Commercial Applications

•  Pipelined microprocessor applications

•  NoC related applications



•  Ancajas, D.M.; Nickerson, J.M.; Chakraborty, K.; Roy, S., "HCI-Tolerant NoC router microarchitecture," in Design Automation Conference (DAC), 2013 50th ACM/EDAC/IEEE , vol., no., pp.1-10, May 29 2013-June 7 2013



Patent Information:
Computer Science
For Information, Contact:
Christian Iverson
Utah State University
Sanghamitra Roy Koushik Chakraborty Dean Ancajas