On information rates over a binary input channel

TL;DR

This paper improves the lower bounds on the capacity of binary-input AWGN channels by introducing new schemes that achieve higher information rates with fewer sign transitions, narrowing the gap to the upper bound.

Contribution

It presents novel achievability schemes that outperform previous methods in binary AWGN channels, reducing the gap to the spectral constraint upper bound.

Findings

Achieves higher information rates than previous bounds.

Reduces the gap to the upper spectral constraint bound to 0.93 bits at high SNR.

Uses fewer sign transitions in the binary signals.

Abstract

We study communication systems over band-limited Additive White Gaussian Noise (AWGN) channels in which the transmitter output is constrained to be symmetric binary (bi-polar). In this work we improve the original Ozarov-Wyner-Ziv (OWZ) lower bound on capacity by introducing new achievability schemes with two advantages over the studied OWZ scheme which is based on peak-power constrained pulse-amplitude modulation. Our schemes achieve a moderately improved information rate and do so with much less sign transitions of the binary signal. The gap between the known upper-bound based on spectral constrains of bi-polar signals and our achievable lower bound is reduced to 0.93 bits per Nyquist interval at high SNR.