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.

/pdf/a-key-6g-challenge-and-opportunity-connecting-the-base-of-385d3hceqi.pdf

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

Cloud computing is an emerging technology paradigm that migrates current technological and computing concepts into utility-like solutions similar to electricity and water systems. Clouds bring out a wide range of benefits including configurable computing resources, economic savings, and service flexibility. However, security and privacy concerns are shown to be the primary obstacles to a wide adoption of clouds. The new concepts that clouds introduce, such as multi-tenancy, resource sharing and outsourcing, create new challenges to the security community. Addressing these challenges requires, in addition to the ability to cultivate and tune the security measures developed for traditional computing systems, proposing new security policies, models, and protocols to address the unique cloud security challenges. In this work, we provide a comprehensive study of cloud computing security and privacy concerns. We identify cloud vulnerabilities, classify known security threats and attacks, and present the state-of-the-art practices to control the vulnerabilities, neutralize the threats, and calibrate the attacks. Additionally, we investigate and identify the limitations of the current solutions and provide insights of the future security perspectives. Finally, we provide a cloud security framework in which we present the various lines of defense and identify the dependency levels among them. We identify 28 cloud security threats which we classify into five categories. We also present nine general cloud attacks along with various attack incidents, and provide effectiveness analysis of the proposed countermeasures.

Cloud Computing Security: A Survey

Disastrous events are one of the most challenging applications of multihop ad hoc networks due to possible damages of existing telecommunication infrastructure. The deployed cellular communication infrastructure might be partially or completely destroyed after a natural disaster. Multihop ad hoc communication is an interesting alternative to deal with the lack of communications in disaster scenarios. They have evolved since their origin, leading to different ad hoc paradigms such as MANETs, VANETs, DTNs, or WSNs. This paper presents a survey on multihop ad hoc network paradigms for disaster scenarios. It highlights their applicability to important tasks in disaster relief operations. More specifically, the paper reviews the main work found in the literature, which employed ad hoc networks in disaster scenarios. In addition, it discusses the open challenges and the future research directions for each different ad hoc paradigm.

A survey on multihop ad hoc networks for disaster response scenarios

Cognitive radio has attracted considerable attention because of its ability to make full use of the available spectrum resources for wireless terrestrial communication networks. In addition, the satellite communication scenario, which requires a transparent air interface to integrated/hybrid Satellite-Terrestrial communication systems and provides a supplement for other multimedia services, will cause frequency scarcity. Satellite communication systems based on cognitive radio are available under scenarios that involve transmission with changing communications. In this paper, a cooperative spectrum-sensing algorithm based on a time or bandwidth-based cooperative spectrum-sensing model of an integrated/hybrid cooperative satellite communication system is proposed. Moreover, the concept of weighted cooperative spectrum sensing is introduced. Compared with the traditional single-user spectrum-sensing algorithm, the cooperative spectrum sensing is able to cope with the interference to the primary user caused by a secondary user better. In addition, multiple earth stations that use some part of the bandwidth cooperatively to perform spectrum sensing throughout the whole frame can detect the presence of primary user in time. The satellite component combines the sensing results from earth stations to reach a final decision, and the optimal combination weights to maximize the detection probability of the secondary user are obtained. Numerical results that demonstrate the performance of the proposed algorithm are presented. Copyright © 2015 John Wiley & Sons, Ltd.

Joint cooperative spectrum sensing and channel selection optimization for satellite communication systems based on cognitive radio

Preface. Contributors. About the Editor. 1. Algorithms for Mobile Ad Hoc Networks (Azzedine Boukerche, Daniel Camara, Antonio A.F. Loureiro, and Carlos M.S. Figueiredo). 2. Establishing a Communication Infrastructure in Ad Hoc Networks (Michel Barbeau, Evangelos Kranakis, and Ioannis Lambadaris). 3. Robustness Control for Network-Wide Broadcast in Multihop Wireless Networks (Paul Rogers and Nael B. Abu-Ghazaleh). 4. Encoding for Efficient Data Distribution in Multihop Ad Hoc Networks (Luciana Pelusi, Andrea Passarella, and Marco Conti). 5. A Taxonomy of Routing Protocols for Mobile Ad Hoc Networks (Azzedine Boukerche, Mohammad Z. Ahmad, Damla Turgut, and Begumhan Turgut). 6. Adaptive Backbone Multicast Routing for Mobile Ad Hoc Networks (Chaiporn Jaikaeo and Chien-Chung Shen). 7. Effect of Interference on Routing in Multihop Wireless Networks (Vinay Kolar and Nael B. Abu-Ghazaleh). 8. Routing Protocols in Intermittently Connected Mobile Ad Hoc Networks and Delay-Tolerant Networks (Zhensheng Zhang). 9. Transport Layer Protocols for Mobile Ad Hoc Networks (Lap Kong Law, Srikanth V. Krishnamurthy, and Michalis Faloutsos). 10. ACK-Thinning Techniques for TCP in MANETs (Stylianos Papanastasiou, Mohamed Ould-Khaoua, and Lewis M. MacKenzie). 11. Power Control Protocols for Wireless Ad Hoc Networks (Junhua Zhu, Brahim Bensaou, and Farid Nait-Abdesselam). 12. Power Saving in Solar-Powered WLAN Mesh Networks (Amir A. Sayegh, Mohammed N. Smadi, and Terence D. Todd). 13. Reputation-and-Trust-Based Systems for Ad Hoc Networks (Avinash Srinivasan, Joshua Teitelbaum, Jie Wu, Mihaela Cardei, and Huigang Liang). 14. Vehicular Ad Hoc Networks: An Emerging Technology Toward Safe and Efficient Transportation (Maen M. Artimy, William Robertson, and William J. Phillips). 15. Performance Issues in Vehicular Ad Hoc Networks (Maria Kihl and Mihail L. Sichitiu). 16. Cluster Interconnection in 802.15.4 Beacon-Enabled Networks (Jelena Misic and Ranjith Udayshankar). Index.

Algorithm and protocols for wireless and mobile ad hoc networks

After the East Japan Great Earthquake in 2011, a robust network communication has been one of significant subjects for the study of Disaster Information System. Then, DTN (Delay Tolerant Network) has been focused for the effective methods for such inoperable network circumstances. However, when DTN is applied for the local areas, there are some problems such as message delivery rate and latency because there are fewer roads, cars, and pedestrians than in urban areas. Therefore, we propose the Enhanced Media Coordinate System for DTN to the architecture in order to provide the Data Triage, Node Selection based on its Territory, and Dynamic FEC (Forward Error Correction). In this paper, the proposed Data Triage Methods that provide the data priority by the user policy and the application type is especially explained, and the results of the computational simulation by the GIS map of a Japanese coastal town is reported. Then, the results are discussed for the future studies of DTN for Disaster Information Network System in local areas.

Proposal of Data Triage Methods for Disaster Information Network System Based on Delay Tolerant Networking

On March 11, 2011, a massive 9.0 magnitude earthquake hit the Pacific Ocean nearby Northeastern Japan causing damage with blackouts, fire, tsunami and nuclear plant crisis. A devastating tsunami swept over cities and farmland in the northern part of the country and set off warnings as far away the west coast of the United States and South America. Recorded as 9.0 on the Richter scale, it was the most powerful quake ever to hit the country. This paper is the report of communication traffic analysis and connectivity in Iwate Prefectural University located in middle area of Iwate prefecture in Japan after quake was hit. Although network conditions were not enough to held multimedia communication and many network machines were damaged, mail and SNS services were possible to use under the conditions. Moreover, the activity in the university at the disaster and future requirements for disaster information system is discussed.

Disaster Information System from Communication Traffic Analysis and Connectivity (Quick Report from Japan Earthquake and Tsunami on March 11th, 2011)

In the actual disaster case, there is a certain possibility that electric power line is damaged and power energy cannot be supplied to those communication network devices, and eventually those wireless LANs cannot be functioned. Although mobile wireless network is easy to reconstruct than wired network, there may be the case that network disconnection is not affordable after disaster. That is, Disaster Information System needs a robust Never Die Network (NDN) which will be unaffected by any changes in environment after severe disaster. Satellite Network System is one of possible solution for such a severe disaster, but it has some problems like low throughput, large latency, high cost, and so on. On the other hands, single wireless communication like IEEE802.11a/b/g also have some problems like a possible transmission distance, throughput limitation for maintaining QoS for urgent user's situations. Therefore, NDN needs to consider about additional functions for these problems of Satellite and Wireless Network System. In this paper, we introduce Satellite System for optimal transmission control method in Cognitive Wireless Network in order to consider with severe disaster. First, as our previous study, proper wireless link and route selection is held by Extend AHP and Extend AODV with Min-Max AHP value methods for optimal transmission control in Cognitive Wireless Network. Then, check-alive function, alternate data transmission function, possible alternative route suggestion, and network reconfiguration are introduced to our proposed Disaster Information Network by using Satellite System. In the simulation, ns2 are used for the computational results to the effectiveness of the suggested transmission methods in the hybrid system of cognitive wireless and satellite network system.

Never Die Network Extended with Cognitive Wireless Network for Disaster Information System

On March 11, 2011, a massive 9.0 magnitude earthquake hit the Pacific Ocean nearby Northeastern Japan causing damage with blackouts, fire, tsunami and nuclear plant crisis. A devastating tsunami swept over cities and farmland in the northern part of the country and set off warnings as far away the west coast of the United States and South America. Recorded as 9.0 on the Richter scale, it was the most powerful quake ever to hit the country. Because of this large scale disaster, communication network was break down in wide area of the Northern Japan, and the coast side was especially heavily damaged. The disconnection of communication system brought serious problems for rescue and evacuation, and it was also caused the delay of the activities. This paper is the report of network relief activities for reactivating communication system in the coast side of Iwate Prefecture, and it is discussed about what kinds of requirements is needed for such a large scale disaster. With our activities, electricity and fuel are seriously needed at the first. Then, satellite system was effective for reactivating network connection in the severe disaster area.

Network Relief Activity with Cognitive Wireless Network for Large Scale Disaster

In this paper QOS Control of realtime multimedia communication system under heterogeneous environment by, the wired and the wireless networks is proposed. In our suggested system, as channel coding, FEC (Forward Error Correction) method with Reed-Solomon coding is introduced to reduce the packet error rate on the wireless network. On the other hand, as source coding, transcoding methods including transformation of various video codings such as M-JPEG, MPEG and Quicktime, controls of Q-factor within a frame, frame rate and color depth is introduced to maintain the required QOS, particularly the end-to-end throughput. The increases of the required bandwidth by redundant packet addition with FEC can be suppressed by the transcoding functions while the packet error rate is reduced to the accepted value. In order to verify the functionality and the efficiency in our suggested system, numerical simulation was carried out. As the result, our suggested system by combination of transcoding and FEC could correct the packet error rate with accepted order while maintaining the frame rate and the amount of data transform at a constant.

Kazuo Takahata

Papers

Proposal of Data Triage Methods for Disaster Information Network System Based on Delay Tolerant Networking

Disaster Information System from Communication Traffic Analysis and Connectivity (Quick Report from Japan Earthquake and Tsunami on March 11th, 2011)

Never Die Network Extended with Cognitive Wireless Network for Disaster Information System

Network Relief Activity with Cognitive Wireless Network for Large Scale Disaster

Packet error and frame rate controls for real time video stream over wireless LANs