Providing connectivity to around half of the world population living in rural or underprivileged areas is a tremendous challenge, but, at the same time, a unique opportunity. Access to the Internet would provide the population living in these areas a possibility to progress on the educational, health, environment, and business levels. In this article, a survey of technologies for providing connectivity to rural areas, which can help address this challenge, is provided. Although access/fronthaul and backhaul techniques are discussed in this article, it is noted that the major limitation for providing connectivity to rural and underprivileged areas is the cost of backhaul deployment. In addition, energy requirements and cost-efficiency of the studied technologies are analyzed. In fact, the challenges faced for deploying an electricity network, as a prerequisite for deploying communication networks, are huge in these areas, and they are granted an important share of the discussions in this article. Furthermore, typical application scenarios in rural areas are discussed, and several country-specific use cases are surveyed. The main initiatives by key international players aiming to provide rural connectivity are also described. Moreover, directions for the future evolution of rural connectivity are outlined in this article. Although there is no single solution that can solve all rural connectivity problems, building gradually on the current achievements in order to reach ubiquitous connectivity, while taking into account the particularities of each region and tailoring the solution accordingly, seems to be the most suitable path to follow.

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A Key 6G Challenge and Opportunity—Connecting the Base of the Pyramid: A Survey on Rural Connectivity

Previous survey articles on Low-Powered Wide-Area Networks (LPWANs) lack a systematic analysis of the design goals of LPWAN and the design decisions adopted by various commercially available and emerging LPWAN technologies, and no study has analysed how their design decisions impact their ability to meet design goals. Assessing a technology's ability to meet design goals is essential in determining suitable technologies for a given application. To address these gaps, we have analysed six prominent design goals and identified the design decisions used to meet each goal in the eight LPWAN technologies, ranging from technical consideration to business model, and determined which specific technique in a design decision will help meet each goal to the greatest extent. System architecture and specifications are presented for those LPWAN solutions, and their ability to meet each design goal is evaluated. We outline seventeen use cases across twelve domains that require large low power network infrastructure and prioritise each design goal's importance to those applications as Low, Moderate, or High. Using these priorities and each technology's suitability for meeting design goals, we suggest appropriate LPWAN technologies for each use case. Finally, a number of research challenges are presented for current and future technologies.

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Low-Power Wide-Area Networks: Design Goals, Architecture, Suitability to Use Cases and Research Challenges

Recently, there has been much interest by the cellular network industry in utilizing unlicensed spectrum to expand potential capacity. In particular, two LTE unlicensed technologies gained much attention: licensed-assisted access (LAA) and LTE unlicensed (LTE-U). While these are rapidly entering the market, there are not many studies in the literature that are providing a complete evaluation and comparison of their performance. Available work usually focuses on single technology standalone evaluations. Also, despite the vast body of simulation results by industry and academia, the simulators are not publicly available, and the analytical models proposed in the literature do not offer complex enough frameworks for thorough performance evaluations. To carry out an evaluation study, we have built a comprehensive simulation platform, strictly complying with the standards and specifications of each technology. The models are built upon popular ns-3 simulator, have been designed in close consultation with industry experts, and have been validated through calibration processes and against analytical proposals and experimental platforms. In this paper, we provide a detailed overview, performance evaluation, and comparison of LAA and LTE-U in a wide variety of scenarios, following 3GPP and Wi-Fi Alliance (WFA) guidelines. We show that despite the market is confirming LAA as the leading unlicensed LTE technology, in certain setups, efficient implementations of LTE-U may prove unexpectedly better in coexisting with Wi-Fi. Similarly, the expected behaviors of the LAA LBT procedure can reveal untrue, depending on the traffic or interference patterns and specific implementation details, even in Wi-Fi. This paper also includes scenarios involving TCP, which is a rarely treated topic in the literature in the context of LTE and Wi-Fi coexistence. The end-to-end and full protocol stack simulation platform is openly available to foster results' reproducibility and collaborative development.

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Evaluating unlicensed LTE technologies: LAA vs LTE-U

Providing connectivity to around half of the World population living in rural or underprivileged areas is a tremendous challenge, but also a unique opportunity. In this paper, a survey of technologies for providing connectivity to rural areas, and that can help address this challenge, is provided. Fronthaul and backhaul techniques are discussed. In addition, energy and cost efficiency of the studied technologies are analyzed. Typical application scenarios in rural areas are discussed, and several country-specific use cases are surveyed. Directions for future evolution of rural connectivity are outlined.

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A Key 6G Challenge and Opportunity - Connecting the Remaining 4 Billions: A Survey on Rural Connectivity

Narrowband Internet of Things: A Comprehensive Study

Actually many Internet of Things (IoT) applications and architectures are being deployed in order to support urban area applications, as for example smart cities. However, other important applications are being deployed in rural areas, as for example agribusiness, in which wireless connectivity is one of the most important issues because wireless broadband commercial technologies are not sustainable from the business model view. In order to attend the actual demand of rural areas, the present work proposes two study cases that optimize coverage and low energy consumption joining LTE and LoRaWAN wireless access technologies. The proposal architecture is based on an element called Intelligent Terminal (IT), which is a gateway that is composed by LTE and LoRaWAN interfaces. The first study case represents a terrestrial vehicular case and the second one represents an unmanned aerial vehicle (UAV) case. The terrestrial study case is used as a reference to get a quantified gain of using UAVs. Considering that every scenario has particularities in terrestrial relief characteristics, it was obtained coverage information of five scenarios with different radius. When the radius coverage is increased, usability of UAV becomes more important. In average, for radius equal to 45 km and an UAV height equal to 50 m the gain of using UAVs is equal to 2 times the coverage than using a terrestrial solution. Other important contribution are parameters of a linear equation that estimate the average coverage gain based on any arbitrary UAV altitude.

Rural area deployment of internet of things connectivity: LTE and LoRaWAN case study

Notwithstanding the value of Long Term Evolution (LTE) towards an improved user experience in next-generation networks, its associated high complexity is known to place computational and time burdens on testing tasks involving real-world platforms. Simulation is currently the tool most widely used to tackle this issue. LENA, for instance, is an open source simulator based on ns-3 that allows the design, evaluation, and validation of LTE networks. Despite of modeling the main LTE elements and interfaces, one limitation of LENA is that it docs not support the use of external traffic entities in conjunction with the simulation. In this paper, we describe how the ns-3 LENA LTE framework can be customized for use in an emulation-based test environment that allows a wider variety of real-world applications to be run over the simulated links. To validate our emulation results, we use as benchmark a testbed that differs from the aforementioned test environment in that the ns-3 server running the simulated network is replaced with a network made up of real-world platforms. Initial validation results, based on limited tests using an industry-standard VoIP test tool and iperf throughput tool, demonstrate that ns-3 LTE models can deliver voice quality and latency as good as an experimental testbed using actual LTE equipment over a range of signal-to-noise ratios. Similar conclusions arc also drawn for throughput, thus confirming the suitability of our emulation approach as a viable means to predict performance in real LTE networks. The good agreement of our experimental results is possible not only because the same functionality is implemented in both experiments but due to the use of the same traffic generation tools in the simulated and real-world LTE networks not -- possible in standard LENA simulation.

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Performance comparison of a custom emulation-based test environment against a real-world LTE testbed

Wireless technology is one of the enabler for Internet of Things (IoT) with a tremendous expected growth in the next years. The variety of wireless technologies to support different requirements like coverage or network architecture transform the wireless industry in a very competitive segment. There are many solutions for short and middle range IoT communication however, there is not still a long range solution that is broader adopted by the industry, which is generally know as Low-Power Wide-Area (LPWAN) technology. There LPWAN has not been designed for mobile network but the 3rd Generation Partnership Project (3GPP), that is responsible for 3G and 4G standardization, created the new technology that is named Narrow-Band IoT (NB-IoT) which intends to be widely adopted by the Operators. This article presents a summary of the NB-IoT specifications and some comparisons with others LPWAN technologies.

Evolution of long term narrowband-IoT

Cognitive radio is an advanced technology being used to improve the efficiency of spectrum usage, as well as to sense the environment and change its radio parameters to avoid interference with primary users (PU) or secondary users (SU). This strategy can also be applied to avoid jamming interference in military defense networks. Also, while LTE (Long-Term Evolution) technology has been successfully deployed worldwide for broadband civil applications, it has also evolved to support Public Safety and National Defense applications. Security and QoS (Quality of Service) features have proven to be especially useful when applied to the Defense sector, but fail to provide protection against intentional jamming attacks, which can interrupt OTA (Over-the-Air) communications. So far, there is no formal 3GPP (3rd Generation Partnership Project) report addressing the jamming issue, although mechanisms to mitigate OTA vulnerabilities have been proposed in the literature, mainly by authors suggesting changes in the LTE physical layer standard. This paper presents two innovative strategies based on cognitive radio technology to prevent jamming attacks, without the need to implement changes in the 3GPP standard or in the base station/terminal hardware. These advantages can accelerate the deployment and reduce the costs using the same infrastructure equipment. A computational simulation is performed in order to compare scenarios involving Cell Frequency Reconfiguration and Frequency Hopping Strategies. Performance results are shown considering video streaming service with different jamming scenarios.

4G/LTE Networks for Mission-Critical Operations: A Cognitive Radio Approach

LTE (Long-Term Evolution) has been successfully deployed worldwide and the respective standardization body, 3GPP (3rd Generation Partnership Project), is committed to continuously evolve the technology and introduce new features applied to a variety of sectors, such as Network Operators, Industrial, Public Safety and National Defense. Considering this last sector, the existing features of Security and QoS (Quality of Service) are very useful when applied to the Defense industry, but cannot provide protection against intentional jamming attacks, which can interrupt OTA (Over-the-Air) communications. So far, there is no formal 3GPP report addressing the jamming issue, although mechanisms to mitigate OTA vulnerabilities have been proposed in the literature, mainly requiring changes in the LTE physical layer standard. This paper presents two innovative strategies to prevent jamming attacks, without changes in the 3GPP standard or in the base station and terminal hardware. These advantages can accelerate the deployment and reduce the costs by using the same infrastructure equipment. A computational simulation is performed in order to compare scenarios involving Cell Frequency Reconfiguration and Frequency Hopping Strategies. Performance results are shown considering video streaming service with different jamming scenarios.

Jorge Seki

Papers

Rural area deployment of internet of things connectivity: LTE and LoRaWAN case study

Performance comparison of a custom emulation-based test environment against a real-world LTE testbed

Evolution of long term narrowband-IoT

4G/LTE Networks for Mission-Critical Operations: A Cognitive Radio Approach

LTE jamming mitigation based on frequency hopping strategies