Stochastic computing and its application to sound source localization

Abstract

Stochastic computing (SC) is an alternative computing paradigm that processes data in the form of long uniform bit-streams rather than conventional compact weighted binary numbers. SC is fault-tolerant and can compute on small, efficient circuits, promising advantages over conventional arithmetic for newer and smaller computer chips. However, SC is primarily used in scientific research, not in practical applications. Digital sound source localization (SSL) locates speakers using multiple microphones in cell phones, laptops, and other voice-controlled devices. SC has not been integrated to SSL in practice nor in theory until now. In this work, for the first time to the best of our knowledge, we replace a conventional computational block of an existing SSL algorithm with an SC-based design and implement a working SC-based sound source localizer. The practical part of this work shows that the proposed stochastic circuits do not rely on conventional analog-to-digital conversion and can process data in the form of pulse-width-modulated (PWM) signals. The proposed SC design consumes up to 39% less area than the conventional reference design. The SC-based design can consume less power depending on the computational accuracy, for example, 6% less power consumption for 3-bit inputs. The presented stochastic circuit is not limited to SSL and is readily applicable to other practical applications.