  The ever-increasing demand of mobile Internet and multimedia services poses
unique and significant challenges for current and future generation wireless
networks. These challenges are mainly relating to the support of massive
ubiquitous connectivity, low latency and highly efficient utilization of
spectrum resources. Therefore, it is vital to consider them extensively prior
to design and deployment of future wireless networks. To this end, the present
article provides a comprehensive overview of a particularly promising and
effective wireless technology, namely, visible light communication (VLC). In
this context, we initially provide a thorough overview of frequency domain
multiple access techniques for single and multi-carrier systems, which is then
followed by an in depth discussion on the technical considerations of optical
code division multiple access techniques and their adoption in indoor VLC
applications. Furthermore, we address space division multiple access and,
finally, we revisit and analyze the distinct characteristics of a new
technology, namely, non-orthogonal multiple access, which has been proposed
recently as a particularly effective solution.
