Visible light communication in conjunction with solid state lighting has become an emerging area of interest to achieve
lighting and wireless communication simultaneously in an indoor environment. It is anticipated to be a low cost
supplement to existing wireless communication technologies. Most existing work has primarily focused on a
unidirectional downlink using visible light spectra. The appropriate choice of an uplink to achieve bidirectional
communication is a big challenge. In this paper, candidate options of the uplink are compared in terms of device
performance, light safety, background interference, and path loss. In visible light communication, white light emitting
diodes as optical transmitters are also characterized in terms of impulse response and electrical spectrum. A digital preequalization
idea to increase their bandwidth is proposed. Performance of the downlink visible light communication
system is also experimentally studied in order to demonstrate the feasibility of the proposed design.
Rich atmospheric scattering in the ultraviolet (UV) enables non-line-of sight (NLOS) communications, opening a new
optical paradigm. In this paper, we incorporate an experimentally validated NLOS channel path loss model and
quantitatively predict the performance of a combination of modulation and coding techniques. Our study includes OOK,
PPM, MPPM, repetition coding and trellis coding. We consider both Poisson and Gaussian noise assumptions,
appropriate for different operating regimes, with a focus on achievable range as a critical parameter in NLOS operation.