The exponentially increasing demand for high-speed wireless communications will no longer
be satisfied by the traditional radio frequency (RF) in the near future due to its limited spectrum
and overutilization. To resolve this imminent issue, industrial and research communities have
been looking into alternative technologies for communication. Among them, visible light communication
(VLC) has attracted much attention because it utilizes the unlicensed, free and safe
spectrum, whose bandwidth is thousand times larger than the entire RF spectrum. Moreover,
VLC can be integrated into existing lighting systems to offer a dual-purpose, cost-effective and
energy-efficient solution for next-generation small-cell networks (SCNs), giving birth to the
concept of optical attocell networks.
Most relevant works in the literature rely on system simulations to quantify the performance
of attocell networks, which suffer from high computational complexity and provide limited
insights about the network. Mathematical tools, on the other hand, are more tractable and
scalable and are shown to closely approximate practical systems. The presented work utilizes
stochastic geometry for downlink evaluation of optical attocell networks, where the co-channel
interference (CCI) surpasses noise and becomes the limiting factor of the link throughput. By
studying the moment generating function (MGF) of the aggregate interference, a theoretical
framework for modeling the distribution of signal-to-interference-plus-noise ratio (SINR) is
presented, which allows important performance metrics such as the coverage probability and
link throughput to be derived. Depending on the source of interference, CCI can be classified
into two categories: inter-cell interference (ICI) and intra-cell interference. In this work,
both types of interference are characterized, based on which effective interference mitigation
techniques such as the coordinated multipoint (CoMP), power-domain multiplexing and successive
interference cancellation (SIC) are devised. The proposed mathematical framework is
applicable to attocell networks with and without such interference mitigation techniques.
Compared to RF networks, optical attocell networks are inherently more secure in the physical
layer because visible light does not penetrate through opaque walls. This work analytically
quantifies the physical-layer security of attocell networks from an information-theoretic point of
view. Secrecy enhancement techniques such as AP cooperation and eavesdropper-free protected
zones are also discussed. It is shown that compared to AP cooperation, implementing secrecy
protected zones is more effective and it can contribute significantly to the network security
