Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed

Telecommunications media for the delivery of educational programming

The technical characteristics of various telecommunications media are examined for incorporation into educational networks. FM radio, AM radio, and VHF and UHF television are considered along with computer-aided instruction. The application of iteration networks to library systems, and microform technology are discussed. The basic principles of the communications theory are outlined, and the operation of the PLATO 4 random access system is described

Software-defined Networking enabled Resource Management and Security Provisioning in 5G Heterogeneous Networks

Due to the explosive growth of mobile data traffic and the shortage of spectral resources, 5G networks are envisioned to have a densified heterogeneous network (HetNet) architecture, combining multiple radio access technologies (multi-RATs) into a single holistic network. The co-existing of multi-tier architectures bring new challenges, especially on resource management and security provisioning, due to the lack of common interface and consistent policy across HetNets. In this thesis, we aim to address the technical challenges of data traffic management, coordinated spectrum sharing and security provisioning in 5G HetNets through the introduction of a programmable management platform based on Software-defined networking (SDN). To address the spectrum shortage problem in cellular networks, cellular data traffic is efficiently offloaded to the Wi-Fi network, and the quality of service of user applications is guaranteed with the proposed delay tolerance based partial data offloading algorithm. A two-layered information collection is also applied to best load balancing decision-making. Numerical results show that the proposed schemes exploit an SDN controller\u27s global view of the HetNets and take optimized resource allocation decisions. To support growing vehicle-generated data traffic in 5G-vehicle ad hoc networks (VANET), SDN-enabled adaptive vehicle clustering algorithm is proposed based on the real-time road traffic condition collected from HetNet infrastructure. Traffic offloading is achieved within each cluster and dynamic beamformed transmission is also applied to improve trunk link communication quality. To further achieve a coordinated spectrum sharing across HetNets, an SDN enabled orchestrated spectrum sharing scheme that integrates participating HetNets into an amalgamated network through a common configuration interface and real-time information exchange is proposed. In order to effectively protect incumbent users, a real-time 3D interference map is developed to guide the spectrum access based on the SDN global view. MATLAB simulations confirm that average interference at incumbents is reduced as well as the average number of denied access. Moreover, to tackle the contradiction between more stringent latency requirement of 5G and the potential delay induced by frequent authentications in 5G small cells and HetNets, an SDN-enabled fast authentication scheme is proposed in this thesis to simplify authentication handover, through sharing of user-dependent secure context information (SCI) among related access points. The proposed SCI is a weighted combination of user-specific attributes, which provides unique fingerprint of the specific device without additional hardware and computation cost. Numerical results show that the proposed non-cryptographic authentication scheme achieves comparable security with traditional cryptographic algorithms, while reduces authentication complexity and latency especially when network load is high

TRANSPORT PROTOCOL AND FLOW CONTROL FOR IP-BASED BROADBAND AERONAUTICAL SATELLITE NETWORKS

The IP-based broadband aeronautical satellite network will provide numerous new applications and services for both airspace system operations and passenger communications. However, the interoperation between a satellite system and the exiting terrestrial Internet infrastructure introduces new challenges. In this thesis, we recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the future IP-based aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. Based on the observation that it is difficult for an end-to-end TCP solution to solve the performance problem effectively, we proposed a new splitting based transport protocol, called Aeronautical Transport Control Protocol (AeroTCP). The main idea of AeroTCP is the fixed window flow control, adaptive congestion control, and super fast error control. Simulation results showed that AeroTCP can achieve high utilization of satellite channel and fairness

Navigation/traffic control satellite mission study. Volume 2 - Systems analyses

Systems analysis of spacecraft network for transoceanic traffic contro

Dynamic Pricing, Advanced Metering, and Demand Response in Electricity Markets

Presents an overview and analysis of the possible approaches to bringing an active demand side into electricity markets. Part of a series of research reports that examines energy issues facing California

Security Improvements for the Automatic Identification System

The Automatic Identification System (AIS) is used aboard the vast majority of sea-going vessels in the world as a collision avoidance tool. Currently, the AIS operates without any security features, which make it vulnerable to exploits such as spoofing, hijacking, and replay attacks by malicious parties. This paper examines the work that has been done so far to improve AIS security, as well as the approaches taken on similar problems in the aircraft and vehicular mobile ad-hoc network (MANET) industries. The first major contribution of this paper is the implementation of a Software Defined Radio (SDR) AIS transmitter and receiver which can be used to conduct vulnerability analysis and test the implementation of new security features. The second contribution is the design of a novel authentication protocol which overcomes the existing vulnerabilities in the AIS system. The proposed protocol uses time-delayed hash-chain key disclosures as part of a message authentication code (MAC) appended to automatic position reports to verify the authenticity of a user. This method requires only one additional time slot for broadcast authentication compared to the existing standard and is a significant reduction in message overhead requirements compared to alternative approaches that solely rely on public key infrastructure (PKI). Additionally, there is an embedded time stamp, a feature lacking in the existing system, which makes this protocol resistant to replay attacks. A test implementation of the proposed protocol indicates that it can be deployed as a link layer software update to existing AIS transceivers and can be deployed within the current AIS technical standards as an expanded message set

Spectrum Policy and Management

This project provides an examination of the FCC’s policies towards spectrum reallocation. The project examines the National Broadband Plan and how the FCC has approached the goals described within it. The demand for broadband communications has increased dramatically in recent years and has resulted in a predicted spectrum deficit in the near future. In addition to a number of spectrum auctions and their winners the project examines how the redistribution of spectrum impacts the broadband community. The project also provides an examination of spectrum reallocation and policy in other countries, to provide a broader view of spectrum policy. Finally the project examines new spectrum technologies and spectrum usage policies to further examine how the US’s spectrum policies should evolve

Contributions to the development of active RFID systems at the 433 MHz band

Donat el potencial de la tecnologia RFID activa, aquesta tesi contribueix al seu desenvolupament centrant-se en les capes més baixes de la pila de protocols, és a dir, la capa física i la capa d'enllaç de dades. Aquestes capes determinen l'abast de la comunicació entre l'interrogador i les etiquetes, el nombre d'etiquetes que un interrogador pot llegir per segon i el consum d'energia que utilitzen les etiquetes en el procés, que en són els paràmetres de rendiment clau. A la capa física la tesi avalua els aspectes de propagació de la banda 433 MHz en diferents entorns i els compara amb la banda 2.4 GHz. Els resultats demostren que, per a la mateixa potència de transmissió, els sistemes RFID actius que funcionen a la banda 433 MHz aconsegueixen un millor abast de comunicació gràcies a unes millors característiques de propagació. A la capa d'enllaç de dades la tesi proposa LPDQ (Low-Power Distributed Queuing), un nou protocol d'accés al medi, i el compara amb FSA (Frame Slotted ALOHA). LPDQ combina LPL (Low-Power Listening) per a la sincronització de xarxa i DQ (Distributed Queuing) per a la transmissió de dades. En comparació amb el cas òptim de FSA, LPDQ aconsegueix un rendiment proper al màxim teòric (99.5%) independentment del nombre d'etiquetes i redueix el consum d'energia de les etiquetes en més d'un 10%.Dado el potencial de la tecnología RFID activa, esta tesis contribuye a su desarrollo centrándose en las capas más bajas de la pila de protocolos, es decir, la capa física y la capa de enlace de datos. Estas capas determinan el alcance de la comunicación entre el interrogador y las etiquetas, el número de etiquetas que un interrogador puede leer por segundo y el consumo de energía que utilizan las etiquetas en el proceso, que son los parámetros de rendimiento clave. En la capa física la tesis evalúa los aspectos de propagación de la banda 433 MHz en diferentes entornos y los compara con la banda 2.4 GHz. Los resultados demuestran que, para la misma potencia de transmisión, los sistemas RFID activos que funcionan en la banda 433 MHz consiguen un mejor alcance de comunicación gracias a unas mejores características de propagación. En la capa de enlace de datos la tesis propone LPDQ (Low-Power Distributed Queuing), un nuevo protocolo de acceso al medio, y lo compara con FSA (Frame Slotted ALOHA). LPDQ combina LPL (Low-Power Listening) para la sincronización de red y DQ (Distributed Queuing) para la transmisión de datos. En comparación con el caso óptimo de FSA, LPDQ consigue un rendimiento cercano al máximo teórico (99.5%) independientemente del número de etiquetas y reduce el consumo de energía de las etiquetas en más de un 10%.Given the potential of active RFID technology, this thesis contributes to its development by focusing on the lowest layers of the stack, that is, the physical and data-link layers. These layers determine the tag communication range, packet throughput and energy consumption, which are key performance parameters. At the physical layer, the thesis studies propagation aspects of the 433 MHz band in different environments and compares it to the 2.4 GHz band, which is also used in active RFID systems. The results demonstrate that active RFID systems operating at the 433 MHz band can achieve a better communication range at the same transmit power due to better propagation characteristics. At the data-link layer, the thesis proposes LPDQ (Low-Power Distributed Queuing), a new MAC (media access control) protocol, and compares it to FSA (Frame Slotted ALOHA). LPDQ combines LPL (Low-Power Listening) for network synchronization and DQ (Distributed Queuing) for data transmission. Compared to the optimal FSA case, LPDQ can achieve a performance close to the theoretical maximum (99.5%), regardless of the number of tags, and reduces tag energy consumption by more than 10%

A novel MAC Protocol for Cognitive Radio Networks

In Partial Fulfilment of the Requirements for the Degree Doctor of Philosophy from the University of BedfordshireThe scarcity of bandwidth in the radio spectrum has become more vital since the demand for wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum bands and the inefficiency in their utilization have been smartly addressed by the cognitive radio (CR) technology which is an opportunistic network that senses the environment, observes the network changes, and then uses knowledge gained from the prior interaction with the network to make intelligent decisions by dynamically adapting transmission characteristics. In this thesis, recent research and survey about the advances in theory and applications of cognitive radio technology has been reviewed. The thesis starts with the essential background on cognitive radio techniques and systems and discusses those characteristics of CR technology, such as standards, applications and challenges that all can help make software radio more personal. It then presents advanced level material by extensively reviewing the work done so far in the area of cognitive radio networks and more specifically in medium access control (MAC) protocol of CR. The list of references will be useful to both researchers and practitioners in this area. Also, it can be adopted as a graduate-level textbook for an advanced course on wireless communication networks. The development of new technologies such as Wi-Fi, cellular phones, Bluetooth, TV broadcasts and satellite has created immense demand for radio spectrum which is a limited natural resource ranging from 30KHz to 300GHz. For every wireless application, some portion of the radio spectrum needs to be purchased, and the Federal Communication Commission (FCC) allocates the spectrum for some fee for such services. This static allocation of the radio spectrum has led to various problems such as saturation in some bands, scarcity, and lack of radio resources to new wireless applications. Most of the frequencies in the radio spectrum have been allocated although many studies have shown that the allocated bands are not being used efficiently. The CR technology is one of the effective solutions to the shortage of spectrum and the inefficiency of its utilization. In this thesis, a detailed investigation on issues related to the protocol design for cognitive radio networks with particular emphasis on the MAC layer is presented. A novel Dynamic and Decentralized and Hybrid MAC (DDH-MAC) protocol that lies between the CR MAC protocol families of globally available common control channel (GCCC) and local control channel (non-GCCC). First, a multi-access channel MAC protocol, which integrates the best features of both GCCC and non-GCCC, is proposed. Second, an enhancement to the protocol is proposed by enabling it to access more than one control channel at the same time. The cognitive users/secondary users (SUs) always have access to one control channel and they can identify and exploit the vacant channels by dynamically switching across the different control channels. Third, rapid and efficient exchange of CR control information has been proposed to reduce delays due to the opportunistic nature of CR. We have calculated the pre-transmission time for CR and investigate how this time can have a significant effect on nodes holding a delay sensitive data. Fourth, an analytical model, including a Markov chain model, has been proposed. This analytical model will rigorously analyse the performance of our proposed DDH-MAC protocol in terms of aggregate throughput, access delay, and spectrum opportunities in both the saturated and non-saturated networks. Fifth, we develop a simulation model for the DDH-MAC protocol using OPNET Modeler and investigate its performance for queuing delays, bit error rates, backoff slots and throughput. It could be observed from both the numerical and simulation results that when compared with existing CR MAC protocols our proposed MAC protocol can significantly improve the spectrum utilization efficiency of wireless networks. Finally, we optimize the performance of our proposed MAC protocol by incorporating multi-level security and making it energy efficient