Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

A critical analysis of research potential, challenges and future directives in industrial wireless sensor networks

In recent years, Industrial Wireless Sensor Networks (IWSNs) have emerged as an important research theme with applications spanning a wide range of industries including automation, monitoring, process control, feedback systems and automotive. Wide scope of IWSNs applications ranging from small production units, large oil and gas industries to nuclear fission control, enables a fast-paced research in this field. Though IWSNs offer advantages of low cost, flexibility, scalability, self-healing, easy deployment and reformation, yet they pose certain limitations on available potential and introduce challenges on multiple fronts due to their susceptibility to highly complex and uncertain industrial environments. In this paper a detailed discussion on design objectives, challenges and solutions, for IWSNs, are presented. A careful evaluation of industrial systems, deadlines and possible hazards in industrial atmosphere are discussed. The paper also presents a thorough review of the existing standards and industrial protocols and gives a critical evaluation of potential of these standards and protocols along with a detailed discussion on available hardware platforms, specific industrial energy harvesting techniques and their capabilities. The paper lists main service providers for IWSNs solutions and gives insight of future trends and research gaps in the field of IWSNs

Deep pockets, packets, and harbours

Deep Packet Inspection (DPI) is a set of methodologies used for the analysis of data flow over the Internet. It is the intention of this paper to describe technical details of this issue and to show that by using DPI technologies it is possible to understand the content of Transmission Control Protocol/Internet Protocol communications. This communications can carry public available content, private users information, legitimate copyrighted works, as well as infringing copyrighted works. Legislation in many jurisdictions regarding Internet service providers’ liability, or more generally the liability of communication intermediaries, usually contains “safe harbour” provisions. The World Intellectual Property Organization Copyright Treaty of 1996 has a short but significant provision excluding liability for suppliers of physical facilities. The provision is aimed at communication to the public and the facilitation of physical means. Its extensive interpretation to cases of contributory or vicarious liability, in absence of specific national implementation, can prove problematic. Two of the most relevant legislative interventions in the field, the Digital Millennium Copyright Act and the European Directive on Electronic Commerce, regulate extensively the field of intermediary liability. This paper looks at the relationship between existing packet inspection technologies, especially the ‘deep version,’ and the international and national legal and regulatory interventions connected with intellectual property protection and with the correlated liabilities ‘exemptions. In analyzing the referred two main statutes, we will take a comparative look at similar interventions in Australia and Canada that can offer some interesting elements of reflection