This book discusses the smooth integration of optical and RF networks in
5G and beyond (5G+) heterogeneous networks (HetNets), covering both
planning and operational aspects. The integration of high-frequency air
interfaces into 5G+ wireless networks can relieve the congested radio
frequency (RF) bands. Visible light communication (VLC) is now emerging
as a promising candidate for future generations of HetNets.
Heterogeneous RF-optical networks combine the high throughput of visible
light and the high reliability of RF. However, when implementing these
HetNets in mobile scenarios, several challenges arise from both planning
and operational perspectives. Since the mmWave, terahertz, and visible
light bands share similar wave propagation characteristics, the concepts
presented here can be broadly applied in all such bands.
To facilitate the planning of RF-optical HetNets, the authors present an
algorithm that specifies the joint optimal densities of the base
stations by drawing on stochastic geometry in order to satisfy the
users' quality-of-service (QoS) demands with minimum network power
consumption. From an operational perspective, the book explores vertical
handovers and multi-homing using a cooperative framework. For vertical
handovers, it employs a data-driven approach based on deep neural
networks to predict abrupt optical outages; and, on the basis of this
prediction, proposes a reinforcement learning strategy that ensures
minimal network latency during handovers. In terms of multi-homing
support, the authors examine the aggregation of the resources from both
optical and RF networks, adopting a two-timescale multi-agent
reinforcement learning strategy for optimal power allocation.
Presenting comprehensive planning and operational strategies, the book
allows readers to gain an in-depth grasp of how to integrate future
coexisting networks at high-frequency bands in a cooperative manner,
yielding reliable and high-speed 5G+ HetNets.
