Joint Radar and Communication Design: Applications, State-of-the-Art, and the Road Ahead

Sharing of the frequency bands between radar and communication systems has attracted substantial attention, as it can avoid under-utilization of otherwise permanently allocated spectral resources, thus improving efficiency. Further, there is increasing demand for radar and communication systems that share the hardware platform as well as the frequency band, as this not only decongests the spectrum, but also benefits both sensing and signaling operations via the full cooperation between both functionalities. Nevertheless, the success of spectrum and hardware sharing between radar and communication systems critically depends on high-quality joint radar and communication designs. In the first part of this paper, we overview the research progress in the areas of radar-communication coexistence and dual-functional radar-communication (DFRC) systems, with particular emphasis on application scenarios and technical approaches. In the second part, we propose a novel transceiver architecture and frame structure for a DFRC base station (BS) operating in the millimeter wave (mmWave) band, using the hybrid analog-digital (HAD) beamforming technique. We assume that the BS is serving a multi-antenna user equipment (UE) over a mmWave channel, and at the same time it actively detects targets. The targets also play the role of scatterers for the communication signal. In that framework, we propose a novel scheme for joint target search and communication channel estimation, which relies on omni-directional pilot signals generated by the HAD structure. Given a fully-digital communication precoder and a desired radar transmit beampattern, we propose to design the analog and digital precoders under non-convex constant-modulus (CM) and power constraints, such that the BS can formulate narrow beams towards all the targets, while pre-equalizing the impact of the communication channel. Furthermore, we design a HAD receiver that can simultaneously process signals from the UE and echo waves from the targets. By tracking the angular variation of the targets, we show that it is possible to recover the target echoes and mitigate the resulting interference to the UE signals, even when the radar and communication signals share the same signal-to-noise ratio (SNR). The feasibility and efficiency of the proposed approaches in realizing DFRC are verified via numerical simulations. Finally, the paper concludes with an overview of the open problems in the research field of communication and radar spectrum sharing (CRSS)

An improved medium access control protocol for real-time applications in WLANs and its firmware development

The IEEE 802.11 Wireless Local Area Network (WLAN), commonly known as Wi-Fi, has emerged as a popular internet access technology and researchers are continuously working on improvement of the quality of service (QoS) in WLAN by proposing new and efficient schemes. Voice and video over Internet Protocol (VVoIP) applications are becoming very popular in Wi-Fi enabled portable/handheld devices because of recent technological advancements and lower service costs. Different from normal voice and video streaming, these applications demand symmetric throughput for the upstream and downstream. Existing Wi-Fi standards are optimised for generic internet applications and fail to provide symmetric throughput due to traffic bottleneck at access points. Performance analysis and benchmarking is an integral part of WLAN research, and in the majority of the cases, this is done through computer simulation using popular network simulators such as Network Simulator ff 2 (NS-2) or OPNET. While computer simulation is an excellent approach for saving time and money, results generated from computer simulations do not always match practical observations. This is why, for proper assessment of the merits of a proposed system in WLAN, a trial on a practical hardware platform is highly recommended and is often a requirement. In this thesis work, with a view to address the abovementioned challenges for facilitating VoIP and VVoIP services over Wi-Fi, two key contributions are made: i) formulating a suitable medium access control (MAC) protocol to address symmetric traffic scenario and ii) firmware development of this newly devised MAC protocol for real WLAN hardware. The proposed solution shows signifocant improvements over existing standards by supporting higher number of stations with strict QoS criteria. The proposed hardware platform is available off-the-shelf in the market and is a cost effective way of generating and evaluating performance results on a hardware system

Conception et évaluation de nouvelles méthodes pour améliorer les performances des réseaux de nano-communication

Abstract : The field of nanotechnology has undergone very rapid and fascinating development in recent years. This rapid and impressive advance has led to new applications of nanotechnology in the biomedical and military industries, making it a key area of research in multidisciplinary fields. However, the individual processing capacity of nanodevices is very limited, hence the need to design nanonetworks that allow the nanodevices to share information and to cooperate with each other. There are two solutions to establish a nanocommunication system: either by adapting the classical electromagnetic communication to the requirements of nano scale, or by using biological nanosystems inspired by nature such as the molecular communication proposed in the literature. In this thesis, we are interested in the second solution, which is exploiting the potential of biological nanosystems used by nature since billions of years to design biocompatible nanonetworks that can be used inside the human body for medical applications. Nevertheless, the use of this new paradigm is not without challenges. The very low achievable throughput and the Inter-Symbol Interference (ISI) are the most influential problems on the quality of molecular communication. The main objective of this thesis is to design and evaluate new methods inspired by nature in order to enhance the performance of nano-communication systems. To do this, the work is divided into three main parts. In the first part, we enhance the performance of molecular communication by proposing a new method that uses a photolysis-reaction instead of using enzyme to better attenuate ISI. We also propose an optimization of the receiver used in MIMO systems by judiciously choosing the parameters used in its design to reduce the influence of path loss on the quality of the system. The second part proposes a new wired nano-communication system based on self-assembled polymers that build an electrically conductive nanowire to connect the nanodevices to each other. The use of electrons as information carriers drastically increases the achievable throughput and reduces the delay. We study the dynamic process of self-assembly of the nanowire and we propose a bio-inspired receiver that detects the electrons sent through the conductive nanowire and converts them into a blue light. The third part applies the proposed wired nano-communication system to design an architecture ofWired Ad hoc NanoNETworks (WANNET) with a physical layer, Medium Acess Control (MAC) layer and application layer. We also calculate the maximum throughput and we evaluate the performance of the system.Le domaine des nanotechnologies a connu un développement très rapide et fascinant ces dernières années. Cette avancée rapide et impressionnante a conduit à de nouvelles applications dans les industries biomédicale et militaire, ce qui en fait un champ clé de recherche dans des domaines multidisciplinaires. Cependant, la capacité de traitement individuelle des nanodispositifs est très limitée, d'où la nécessité de concevoir des nanoréseaux qui permettent aux nanodispositifs de partager des informations et de coopérer entre eux. Il existe deux solutions pour mettre en place un système de nano-communication: soit en adaptant la communication électromagnétique classiques aux exigences de la nano échelle, soit en utilisant des nanosystèmes inspirés de la nature comme la communication moléculaire. Dans cette thèse, nous nous intéressons à la deuxième solution, qui exploite le potentiel des nanosystèmes biologiques utilisés par la nature depuis des milliards d'années pour concevoir des nanoréseaux biocompatibles pouvant être utilisés à l'intérieur du corps humain pour des applications médicales. Néanmoins, l'utilisation de ce nouveau paradigme n'est pas sans défis. Le très faible débit réalisable et l'Interférence Entre Symboles (IES) sont les problèmes les plus influents sur la qualité de la communication moléculaire. L'objectif principal de cette thèse est de concevoir et d'évaluer de nouvelles méthodes inspirées de la nature afin d'améliorer les performances des systèmes de nano-communication. Pour ce faire, le travail est divisé en trois parties principales. Dans la première partie, nous améliorons les performances de la communication moléculaire en proposant une nouvelle méthode qui utilise une réaction de photolyse pour mieux atténuer l'IES. Nous proposons également une optimisation du receveur utilisé dans les systèmes MIMO en choisissant judicieusement les paramètres utilisés dans sa conception pour réduire l'influence de l'atténuation de trajet sur la qualité du système. La deuxième partie propose un nouveau système de nano-communication filaire basé sur des polymères auto-assemblés qui construisent un nanofil électriquement conducteur pour connecter les nanodispositifs les uns aux autres. L'utilisation d'électrons comme supports d'informations augmente considérablement le débit réalisable et réduit le délai. Nous étudions le processus dynamique d'auto-assemblage du nanofil et nous proposons un receveur bio-inspiré qui détecte les électrons envoyés et les convertit en une lumière bleue. La troisième partie applique le système de nano-communication filaire proposé pour concevoir une architecture d'un nanoréseau ad hoc filaire (Wired Ad hoc NanoNETworks) WANNET avec une couche physique, une couche de contrôle d'accès moyen (Medium Access Control) MAC et une couche d'application. Nous calculons également le débit maximum et nous évaluons les performances du système

Codificação de bloco espaço-tempo na habilitação de sistemas MIMO-OFDM

The available bandwidth in the radio frequency spectrum is decreasing due to the growing number of applications and users. Therefore, in order to ensure a sustainable evolution in this area it is crucial to develop strategies to optimize the spectrum usage. Joining RADAR and communication functionalities in a single terminal represents exactly this same strategy. As such, the two functionalities, which usually compete for the same radio resources, can coexist through a cooperative relation in which they can thrive and cease to introduce interferences in between them. In this dissertation, the integration of both systems is achieved through the use of OFDM as the common waveform. Through the space time/frequency block codes, namely the Tarokh coding it is possible to introduce spatial diversity and orthogonality to the system, therefore increasing the system’s robustness and allowing to use the virtual antenna concept, which enables improved RADAR resolution and detection. In order to evaluate the system’s performance, a simulation platform was developed. In these simulations we start by firstly considering RADAR detection for single and multiple antenna systems and then integrate the radar and communication functionalities. We have verified the good performance levels of the proposed system, which thanks to its low complexity can be an interesting RadCom approach for future wireless systems.A largura de banda disponível no espectro de radio frequência enfrenta uma diminuição face ao crescente número de aplicações e utilizadores. Assim, por forma a assegurar uma evolução sustentável neste campo é fulcral desenvolver estratégias que otimizem o uso do espectro. A junção das funcionalidades RADAR e comunicação num só terminal faz parte dessa estratégia. Desta forma, duas funcionalidades usualmente concorrentes pelos mesmos recursos radio, podem coexistir em cooperação, sem interferência entre ambos. Nesta dissertação a integração dos dois sistemas é conseguida através do uso do OFDM como forma de onda comum. Através de códigos desenhados no espaço-tempo/frequência, nomeadamente a codificação de Tarokh, foi possível introduzir diversidade espacial e ortogonalidade no sistema, aumentando assim a sua robustez e permitindo o uso do conceito de antenas virtuais, que por sua vez possibilitam uma melhoria na resolução e deteção do RADAR. De forma a avaliar o desempenho do sistema desenvolveu-se uma plataforma de simulação. Nesta plataforma começou-se por considerar a deteção RADAR para sistemas com uma e múltiplas antenas, onde posteriormente se integraram as funcionalidades de comunicação. Os resultados obtidos mostraram um excelente desempenho do sistema, que devido à sua baixa complexidade, pode ser um sistema RadCom interessante para os futuros sistemas sem fios.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Unmanned Aircraft Systems in the Cyber Domain

Unmanned Aircraft Systems are an integral part of the US national critical infrastructure. The authors have endeavored to bring a breadth and quality of information to the reader that is unparalleled in the unclassified sphere. This textbook will fully immerse and engage the reader / student in the cyber-security considerations of this rapidly emerging technology that we know as unmanned aircraft systems (UAS). The first edition topics covered National Airspace (NAS) policy issues, information security (INFOSEC), UAS vulnerabilities in key systems (Sense and Avoid / SCADA), navigation and collision avoidance systems, stealth design, intelligence, surveillance and reconnaissance (ISR) platforms; weapons systems security; electronic warfare considerations; data-links, jamming, operational vulnerabilities and still-emerging political scenarios that affect US military / commercial decisions. This second edition discusses state-of-the-art technology issues facing US UAS designers. It focuses on counter unmanned aircraft systems (C-UAS) – especially research designed to mitigate and terminate threats by SWARMS. Topics include high-altitude platforms (HAPS) for wireless communications; C-UAS and large scale threats; acoustic countermeasures against SWARMS and building an Identify Friend or Foe (IFF) acoustic library; updates to the legal / regulatory landscape; UAS proliferation along the Chinese New Silk Road Sea / Land routes; and ethics in this new age of autonomous systems and artificial intelligence (AI).https://newprairiepress.org/ebooks/1027/thumbnail.jp

Emerging Communications for Wireless Sensor Networks

Wireless sensor networks are deployed in a rapidly increasing number of arenas, with uses ranging from healthcare monitoring to industrial and environmental safety, as well as new ubiquitous computing devices that are becoming ever more pervasive in our interconnected society. This book presents a range of exciting developments in software communication technologies including some novel applications, such as in high altitude systems, ground heat exchangers and body sensor networks. Authors from leading institutions on four continents present their latest findings in the spirit of exchanging information and stimulating discussion in the WSN community worldwide