State assignment for fault tolerant stochastic computing with linear finite state machines

Abstract

Stochastic computing (SC), which is an approximate computation with probabilities, has attracted attention owing to its small area, small power consumption and high fault tolerance. In this paper, we focus on the fault tolerance of SC with linear finite state machines (linear FSMs). We show that state assignment of FSMs considerably affects the fault tolerance of FSM-based SC circuits, and present a Markov model representing the impact of the state assignment on the behavior of faulty FSMs. Furthermore, we propose a heuristic algorithm for appropriate state assignment that can mitigate the influence of the transient faults. Experimental results show that the proposed state assignment can significantly reduce the influence of the faults.