New Achievability Results for the Bandlimited Optical Intensity Channel

This paper considers the bandlimited optical intensity channel (BLOIC), which is a basic channel model in optical wireless communications, like the role of the bandlimited additive white Gaussian noise channel in radio-frequency and wireline communications. We investigate achievable information rate of pulse amplitude modulation (PAM) in the BLOIC. A lower bound and an approximation for the information rate are derived, which reduce the gap between existing capacity lower and upper bounds for the BLOIC. Our methods are based on classical results on the discrete-time intersymbol interference (ISI) channels.