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Frameless Network Architecture for User-Centric 5G Radio Access Networks
Published in Hrishikesh Venkatarman, Ramona Trestian, 5G Radio Access Networks: Centralized RAN, Cloud-RAN, and Virtualization of Small Cells, 2017
Xiaodong Xu, Zhao Sun, Jiaxiang Liu
According to the FNA deployments, network topology modeling will be the most fundamental research topic. For the network topology modeling, the traditional single-tier hexagonal grid network deployment model has been implemented for a long time. But with increasing deployments of HetNet and small cells, the multi-tier and ultra-dense HetNet topology cannot be depicted by the traditional hexagonal grids. The actual locations of the small cell BSs inside the future network will be more randomized, especially when the femtocells are randomly deployed in the network and the user can also have the ability to determine the ON/OFF state of their femtocells. The stochastic geometry method with the Poisson point process (PPP) model has been proposed for the aforementioned network topology [18, 19], which provides good tractability for multi-tier HetNet and ultradense small cell deployments. The system outage capacity, mobility management, and interference management can be analyzed with closed-form solutions for many scenarios, which provide valuable theoretical instructions for the actual network planning and performance analyses.
Connectivity Analysis and Modeling in Cognitive Vehicular Networks
Published in Anna Maria Vegni, Dharma P. Agrawal, Cognitive Vehicular Networks, 2018
These definitions and theorems are used in many connectivity analysis and modeling researches in CRNs. In this respect, network connectivity problem has been extensively studied and especially graph theory has been widely used in literature. In [22], the authors analyze the connectivity of CRNs from the perspective of probability and show the relationship among connectivity and density of primary users, density of secondary users, transmission radius of secondary users. [16] studies the impact of interference over the network connectivity in CRNs. By using percolation theory and stochastic geometry, it is observed that connectivity of CRNs will not adversely affect from interference. [12] investigates connectivity challenges in CRNs and compares with mobile ad hoc networks. A mathematical model is proposed in order to show the relation between connectivity and network parameters, i.e., secondary user’s density, primary user’s density, the number of channels, operating frequencies and the distribution of primary users on each channel. In [15], the authors propose a new connectivity metric, termed ‘cognitive natural connectivity’, under single and multi-primary user scenarios for CRNs. This metric has a similar performance with route availability metric which shows the probability of finding a route. Moreover, the complexity is significantly reduced. [11] analyzes the impact of primary users on the connectivity of secondary users in CRNs and show the relation of transmission range of primary users and secondary users on the network connectivity. [23] proposes a cognitive radio graph model which introduces survival probability by considering the number of channels and activities of primary users. Theories and techniques from continuum percolation are used to ensure dynamic connectivity in CRNs.
Joint modelling for rock mechanics
Published in Hans Peter Rossmanith, Mechanics of Jointed and Faulted Rock, 2020
Two classical tessellations in classical stochastic geometry are used in joint models; Voronoi tessellation and Delaunay tessellation. The Voronoi model is obtained from a Poisson process of joint centers that grow at a constant rate up to the formation of polyhedra. The most likely polygons to be formed in this process are hexagons (Santalo 1976). The Delaunay model is also defined by a Poisson point process, but with the points representing block vertices rather than block centers. So, all block faces are triangles connecting adjacent points.
On modeling and performance analysis of non-cooperative multi-antenna multi-user MIMO systems
Published in Journal of the Chinese Institute of Engineers, 2018
Ahmad Kamal Hassan, Muhammad Moinuddin, Ubaid M. Al-Saggaf
The work herein focuses on MU-MIMO systems, which refers to a network formation such that an antenna array at base station (BS) simultaneously serves several single or multiple antenna mobile station (MS) devices in its vicinity (Marzetta 2010; Hassan et al. 2017). There are numerous merits of MU-MIMO systems. Firstly, it is more resilient than point-to-point systems (Vishwanath, Jindal, and Goldsmith 2003). Secondly, economic considerations in terms of the capital expenditure (CAPEX) and the operational expenditure (OPEX) are optimized because the hardware installation of an antenna array is at BS only (ElSawy, Hossain, and Haenggi 2013). Lastly, and more importantly, size constraints for MS devices cannot allow an array of antennas to be fabricated on its platform. The mathematical tool used in this work is based on homogeneous Poisson point processes (PPP) because of its potential in deriving closed-form expressions for the key performance indicators (KPI) (Haenggi et al. 2009; Andrews, Baccelli, and Ganti 2011; Keeler, Błaszczyszyn, and Karray 2013). Thus, for KPIs such as outage probability, spectral efficiency, quality of service (QoS) the point process based stochastic geometry approach is seen as an analytical tool which can give ensemble averages (Haenggi et al. 2009). Moreover, the stochastic geometry approach can model, design, and provide a platform for analysis of random topologies of multi-tier cellular networks.