Ultra Reliable Communication in 5G Networks: A Dependability-based Availability Analysis in the Space Domain

Abstract

As our daily life is becoming more dependent on wireless and mobile services, seamless network connectivity is of utmost importance. Wireless networks are expected to handle the growing demand for applications which require higher capacity, without failure. Therein, wireless connectivity is regarded as an essential requirement for a wide range of applications in order to support exible and cost-e ective services. As part of the fth generation (5G) communication paradigm, ultra reliable communication (URC) is envisaged as an important technology pillar for providing anywhere and anytime services to end users. While most existing studies on reliable communication are not pursued from a dependability perspective, those dependability based studies tend to de ne reliability merely in the time domain. The main objective of this thesis work is to advocate the concept of URC from a dependability perspective in the space domain. Accordingly, we de ne cell availability, system availability, and guaranteed availability for cellular networks. Poisson point process (PPP) and Voronoi tessellation are adopted to model the spatial characteristics of cell deployment in cellular networks. The spatially modeled cellular networks are used to analyze availability and initiate de nitions on cell availability and system availability. Correspondingly, the availability as well as the probability of providing a guaranteed level of availability in a network are analyzed both/either cell-wise and/or system-wise. From this perspective, we investigate in depth the relationship between the signal to interference noise ratio (SINR), capacity or user requirement and achievable availability levels. Extensive simulations are performed for various network scenarios and cell deployments to obtain numerical results based on the cell and system availability de nitions. For SINRbased and capacity-based studies, threshold contours are identi ed in each case in order to further study cell availability under di erent conditions. The importance of deploying di erent types of cells for a cellular network is also highlighted by studying the tradeo between the required transmission power and the obtained system availability. Moreover, de nitions are developed for availability from users' perspective concerning PPP distributed users as well. In a nutshell, this thesis proposes a novel concept referred to as space domain availability as a contribution to the ongoing research activities on URC for future 5G networks. Key words: 5G and URC, dependability and availability, space domain analysis, PPP and Voronoi tessellation, simulations.