Modeling and analysis of wireless networks with interference management
Zeinab Yazdanshenasan Shahraki
Date of Issue2017-06-29
School of Electrical and Electronic Engineering
INFINITUS, Centre for Infocomm Technology
Next generation wireless networks integrate wireless technologies to support massive data requirements and seamless connectivity. Since interference has been the main limiting factor ever since wireless communication evolved, characterizing interference fi eld accurately is an important step toward the design and deployment of wireless networks. Stochastic geometry has emerged as an important tool for the analysis of wireless networks. Initially popular for the modeling of ad hoc and wireless sensor networks, stochastic geometry has recently been adopted for the analysis of cellular and heterogeneous cellular networks as well. In this dissertation, we develop tractable analytical frameworks for the modeling and analysis of interference management techniques in wireless networks by using tools from stochastic geometry. In the context of random spatial models, this dissertation fi rst presents mathematical preliminaries and fundamental tools for the network modeling based on stochastic geometry approaches. We provide an overview on point process models and different approaches used for the analysis of the network. In this work, we focus on the characterization of interference in a Poisson hole process (PHP) model. Interference fi eld in wireless networks is often modeled by a homogeneous Poisson point process (PPP). While it is realistic in modeling the inherent node irregularity and provides meaningful first-order results, PPP falls short in modeling the effect of interference management techniques, which typically introduce some form of spatial interaction among active transmitters. In some applications, such as cognitive radio and device-to-device networks, this interaction may result in the formation of holes that are areas with low interference fi eld strength in an otherwise homogeneous interference field. The resulting interference field can be accurately modeled as a PHP. Despite the importance of PHP in many applications, the exact characterization of interference experienced by a typical node in a PHP is not known. In this dissertation, we first derive several tight upper and lower bounds on the Laplace transform of this interference. Numerical comparisons reveal that the new bounds outperform all known bounds and approximations, and are remarkably tight in all operational regimes of interest. The key in deriving these tight and yet simple bounds is to capture the local neighborhood information around the typical node accurately while simplifying the far fi eld to attain tractability. Ideas for tightening these bounds further by incorporating the effect of overlaps in the holes are also discussed. These results immediately lead to an accurate characterization of the coverage probability of the typical node in a PHP under Rayleigh fading. Second, we develop our proposed approach to study the coverage in a PHP-based heterogeneous cellular network model with dependence. Actual cellular networks reveal spatial separation among base station (BS) deployments belonging to different tiers. While PPP is highly desired for signal-to- interference-plus-noise ratio (SINR) characterization in heterogeneous cellular networks (HCNs) due to its analytical tractability and accuracy, ignoring the spatial correlation of the BSs from different tiers appears unrealistic. We propose a new approach for the analysis of a two-tier HCN when the small cell BSs form a PHP. This model which is recently used for the modeling and analysis of HCNs guarantees a minimum distance between BSs of different tiers while induces spatial correlations among them. We develop the analytical framework that is proposed to capture holes in an ad-hoc network by an equivalent non-homogeneous PPP for the analysis of a HCN. We provide a framework which focuses on a closed access HCN that can be extended to open access strategy. Our third contribution is to focus on the characterization of asymmetric interference fi eld. The asymmetric exclusion zones can be formed by interference management techniques in wireless communication networks. One of the realistic scenarios in this context appears when an exclusion zone is established to protect the communication of the typical user located at an arbitrary location inside the cell, this is unlike most existing works which assume that the symmetric exclusion zones protect the typical user located at the center of the cell. We propose an approach to capture this asymmetric interference fi eld by an equivalent nonhomogeneous PPP. This transformation is also applied for a fi nite network which is more complicated in modeling aggregate interference fi eld, and is more challenging in evaluating the performance of the system. A general framework is provided by the approach to facilitate the analysis and characterize the network performance accurately.