Wideband Multi User Cooperative Networks
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Wideband Multi-User Cooperative Networks
This book details promising communication schemes and channel modeling for a pervasive wireless access network (PWAN). Such a network is formed by nodes equipped with heterogeneous antenna arrangements and placed up to 10 m apart from each other. Nodes can be static when they belong to the infrastructure or have limited mobility when they are carried by a person. This scenario is extremely interesting for relay-based applications and fills the gap between the body area network that has a coverage up to 1 m and the wireless local area network that has a coverage up to 100 m. When a PWAN is jointly considered with high node density, it allows for node cooperations, and idle or infrastructure nodes can support the communication of source-destination pairs. With an adequate signaling scheme, the PWAN can operate as a virtual antenna array and ultimately achieve multiple-input multiple-output (MIMO) gains in a distributed way. Until now these networks have been studied using oversimplified channel models that were frequency flat and designed for cellular low node density networks. The novelty of this book is the study of a PWAN under realistic channel conditions and hardware constraints.
Localization and Posture Recognition via Magneto-Inductive and Relay-Aided Sensor Networks
Author: Henry Ruben Lucas Schulten
language: en
Publisher: Logos Verlag Berlin GmbH
Release Date: 2022-12-15
Body-centric wireless sensor networks are expected to enable future technologies such as medical in-body micro robots or unobtrusive smart textiles. These technologies may advance personalized healthcare as they allow for tasks such as minimally invasive surgery, in-body diagnosis, and continuous activity recognition. However, the localization of individual sensor nodes within such networks or the determination of the entire network topology still pose challenges that need to be solved. This work provides both theoretic and simulative insights to enable the required sub-millimeter localization accuracy of such sensors using magneto-inductive networks. It identifies inherent localization issues such as the asymmetry of the position estimation in magneto-inductive networks and outlines how such issues may be addressed by using passive relays or cooperation. It further proposes a novel approach to recognize the entire structure of a magneto-inductive network using simple impedance measurements and clusters of passive tags. This approach is evaluated extensively by simulation and experiment to demonstrate the feasibility of low-cost human body posture recognition.
Magneto-Inductive Communication and Localization
Author: Gregor Dumphart
language: en
Publisher: Logos Verlag Berlin GmbH
Release Date: 2022-06-15
Utilizing magnetic induction for wireless communication, wireless powering, passive relaying, and localization could enable massive wireless sensor applications with tiny nodes in challenging media, foremost biomedical in-body sensor networks. This work investigates the performance limits of these unique wireless systems with hardly any assumptions. As a foundation, a general system model and an interface to communication theory are developed. A major part of this work identifies two crucial magneto-inductive fading channels: that between randomly oriented coils and that caused by a nearby swarm of resonant passive relay coils. The analysis yields important technological implications. Based thereon, an investigation of wirelessly-powered in-body sensors is conducted, revealing their active and passive data transmission capabilities. Finally, a treatise of magneto-inductive node localization develops algorithms that perform near identified accuracy limits in theory and practice.