Variance based Informatics

Variance-based-Logic: Variance driven Micro-Processor

Source: IEEE ISCAS, 2017

"Exploring the fundamental limits in Digital Computation"

Project Description:

In this research, we explore a novel approach for designing digital circuits that uses the variance of a signal to represent Boolean logic levels. The variance-based logic (VBL) representation enables embedding of rectification and multiplication modules within the basic logic cells and unlike AC-coupled or energy-recovery logic circuits the proposed approach obviates the need for any phase synchronization. As a result, VBL representation can be used for designing low-latency digital circuits that are directly powered by a combination of energy transducers with different frequency and source impedance characteristics. We investigate VBL circuits that can be implemented in a standard CMOS and beyond CMOS devices.

List of publicaitons:

Sri Harsha Kondapalli, Xuan Zhang and Kenji Aono. "Variance-based digital logic for energy harvesting internet-of-things." IEEE International Symposium on Circuits and Systems (ISCAS), 2017.

Variance-based-Logic: Variance driven Communication

Source: Engrxiv, 2019

"Pushing the boundaries of Digital Communication"

Project Description:

In variance-based logic (VBL), information is encoded by the change in the variance of a signal as opposed to the conventional mean-based logic (MBL) where the information is encoded by the change in the mean of the signal. In this research, we compare the fundamental limits on the minimum energy per bit that can be achieved by VBL and MBL representations in high-dimensional signal space. We show that while for MBL representations, the trade-off between the energy-per-bit and the bit-error-rate (BER) is fundamentally constrained by the classical Shannon-limit, using VBL representations it is theoretically possible to achieve arbitrarily small BER while dissipating near-zero energy-per-bit. This surprising result has been experimentally verified for Additive-white-Gaussian-Noise (AWGN) channels using Monte-Carlo simulations. We believe that high-dimensional VBL based encoding could provide a new approach for designing ultra-energy-efficient communication and sensing systems.

List of publicaitons:

Sri Harsha Kondapalli, Xuan Zhang and Shantanu Chakrabartty.Â "Energy-Dissipation Limits in variance-based Computing." Fluctuation and Noise Letters, 2018.
Sri Harsha Kondapalli and Shantanu Chakrabartty. "High-dimensional Variance based Logic for Reliable Communication at Near-zero Energy-per-bit." Engrxiv, 2019.