In-Building Capacity Enhancement using Small Cells in Mobile Networks: An Overview

Abstract

In this paper, we give an overview of the state-of-the-art research studies to present the potential of small cells to address the high capacity demands of in-building users in mobile networks. In doing so, we discuss relevant theoretical backgrounds and carry out performance evaluations of key enabling technologies along with three major directions toward improving the network capacity, including spectrum accessibility, Spectral Efficiency (SE) improvement, and network densification. For the spectrum accessibility, numerous types of Small Cell Base Station (SBS) architectures of a Mobile Network Operator (MNO) are evaluated. For the SE improvement, cognitive radio techniques are evaluated for the Dynamic Spectrum Sharing (DSS) among multiple MNOs in a country. For the network densification, the spectrum reuse is evaluated at both intra-and inter-building levels for a given Co-Channel Interference (CCI) constraint. It is shown that multi-band multi-transceiver enabled small cells operating in the high-frequency millimeter-wave licensed or unlicensed spectrum to realize DSS techniques by exploiting SBS architectures for the spectrum accessibility, a hybrid interweave-underlay spectrum access in Cognitive Radio Networks for the spectral efficiency improvement, and both vertical and horizontal spectrum reuse in small cells deployed densely within buildings for the network densification can address high capacity demand in indoor mobile networks.