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Providing Mobile Phone Access in Rural Areas via Heterogeneous Meshed Wireless Back-Haul Networks
(2011)
This work describes extensions to the well-known Distributed Coordination Function (DCF) model to account for IEEE802.11n point-to-point links. The developed extensions cover adaptions to the throughput and delay estimation for this type of link as well peculiarities of hardware and implementations within the Linux Kernel. Instead of using simulations, the approach was extensively verified on real-world deployments at various link distances. Additionally, trials were conducted to optimize the CWmin values and the number of retries to maximize throughput and minimize delay. The results of this work can be used to estimate the properties of long-distance 802.11 links beforehand, allowing the network to be planned more accurately.
Quantifying the spectrum occupancy in an outdoor 5 GHz WiFi network with directional antennas
(2018)
WiFi-based Long Distance networks are seen as a promising alternative for bringing broadband connectivity to rural areas. A key factor for the profitability of these networks is using license free bands. This work quantifies the current spectrum occupancy in our testbed, which covers rural and urban areas alike. The data mining is conducted on the same WiFi card and in parallel with an operational network. The presented evaluations reveal tendencies for various aspects: occupancy compared to population density, occupancy fluctuations, (joint)-vacant channels, the mean channel vacant duration, different approaches to model/forecast occupancy, and correlations among related interfaces.
Quantifying Interference in WiLD Networks using Topography Data and Realistic Antenna Patterns
(2019)
Avoiding possible interference is a key aspect to maximize the performance in Wi-Fi based Long Distance networks. In this paper we quantify self-induced interference based on data derived from our testbed and match the findings against simulations. By enhancing current simulation models with two key elements we significantly reduce the deviation between testbed and simulation: the usage of detailed antenna patterns compared to the cone model and propagation modeling enhanced by license-free topography data. Based on the gathered data we discuss several possible optimization approaches such as physical separation of local radios, tuning the sensitivity of the transmitter and using centralized compared to distributed channel assignment algorithms. While our testbed is based on 5 GHz Wi-Fi, we briefly discuss the possible impact of our results to other frequency bands.
Open RAN: A Concise Overview
(2025)
Open RAN has emerged as a transformative approach in the evolution of cellular networks, addressing challenges posed by modern applications and high network density. By leveraging disaggregated, virtualized, and software-based elements interconnected through open standardized interfaces, Open RAN introduces agility, cost-effectiveness, and enhanced competition in the Radio Access Network (RAN) domain. The Open RAN paradigm, driven by the O-RAN Alliance specifications, is set to transform the telecom ecosystem. Despite extensive technical literature, there is a lack of succinct summaries for industry professionals, researchers, and policymakers. This paper addresses this gap by providing a concise, yet comprehensive overview of Open RAN. Compared to previous work, our approach introduces Open RAN by gradually splitting up different components known from previous RAN architectures. We believe that this approach leads to a better understanding for people already familiar with the general concept of mobile communication networks. Building upon this general understanding of Open RAN, we introduce key architectural principles, interfaces, components and use-cases. Moreover, this work investigates potential security implications associated with adopting Open RAN architecture, emphasizing the necessity of robust network protection measures.