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Although continuous advances in theoretical modelling of Molecular Communications (MC) are observed, there is still an insuperable gap between theory and experimental testbeds, especially at the microscale. In this paper, the development of the first testbed incorporating engineered yeast cells is reported. Different from the existing literature, eukaryotic yeast cells are considered for both the sender and the receiver, with {\alpha}-factor molecules facilitating the information transfer. The use of such cells is motivated mainly by the well understood biological mechanism of yeast mating, together with their genetic amenability. In addition, recent advances in yeast biosensing establish yeast as a suitable detector and a neat interface to in-body sensor networks. The system under consideration is presented first, and the mathematical models of the underlying biological processes leading to an end-to-end (E2E) system are given. The experimental setup is then described and used to obtain experimental results which validate the developed mathematical models. Beyond that, the ability of the system to effectively generate output pulses in response to repeated stimuli is demonstrated, reporting one event per two hours. However, fast RNA fluctuations indicate cell responses in less than three minutes, demonstrating the potential for much higher rates in the future., Comment: 18 pages, 9 figures (2 of which are not colored) all .png, recently accepted for publication at TMBMC

Device to Device (D2D) Communication is expected to be a core part of the forthcoming 5G Mobile Communication Networks as it promises improvements in energy efficiency, spectral efficiency, overall system capacity, and higher data rates with the use of the same frequencies for different D2D transmissions in short communication distances within the Cell. However, in order to achieve optimum results, it is important, among others, to select wisely the Transmission Mode of the D2D Device. Towards this end, our previous work proposed an intelligent Transmission mode selection approach in a framework that is utilizing Artificial Intelligence (AI) BDIx agents to collectively satisfy the D2D challenges in a Distributed Artificial Intelligent (DAI) manner autonomously and independently. In this paper, as a first step, a literature review focused on related Transmission mode approaches, is performed. Then, our investigated Transmission mode selection approach is further explained with formulas and evaluated based on different threshold values and investigated how these can affect the overall spectral efficiency and power usage of the network in order to achieve the maximum performance. The investigated thresholds(i.e. D2D Device Weighted Data Rate (WDR) and the D2D Device Battery Power Level) and metrics(i.e. WDR) are also further analyzed and formulated. In addition, the effect the transmission power of the D2D links has on the total spectral efficiency and total power consumption of the network, is also examined. This evaluation results arise some interesting findings that can contribute in other approaches that utilized similar or same thresholds. Also, the results obtained demonstrate that with the right tuning of the thresholds and transmission power, one can achieve a significant improvement in the network power usage and total spectral efficiency., Comment: arXiv admin note: text overlap with arXiv:2101.08014

5G D2D Communication promises improvements in energy and spectral efficiency, overall system capacity, and higher data rates. However, to achieve optimum results it is important to select wisely the Transmission mode of the D2D Device to form clusters in the most fruitful positions in terms of Sum Rate and Power Consumption. Towards this end, this paper investigates the use of Distributed Artificial Intelligence (DAI) and innovative to D2D, Machine Learning (ML) approaches to achieve satisfactory results in terms of Spectral Efficiency (SE), Power Consumption (PC) and execution time, with the creation of clusters and backhauling D2D network under existing Base Station/Small Cell. Additionally, one of the major factors that affect the creation of high-quality clusters under a D2D network is the number of the Devices. Therefore, this paper focuses on a small (<=200) number of Devices, with the purpose to identify the limits of each approach in terms of number of devices. Specifically, to identify where it is beneficial to form a cluster, investigate the critical point that gains increases rapidly and at the end examine the applicability of 5G requirements. Additionally, prior work presented a Distributed Artificial Intelligence (DAI) Solution/Framework in D2D and a DAIS Transmission Mode Selection (TMS) plan was proposed. In this paper DAIS is further examined, improved in terms of thresholds evaluation, evaluated, and compared with other approaches (AI/ML). The results obtained demonstrate the exceptional performance of DAIS, compared to all other related approaches in terms of SE, PC, execution time and cluster formation efficiency. Also, results show that the investigated AI/ML approaches are also beneficial for Transmission Mode Selection (TMS) in 5G D2D communication, even with a smaller (i.e., >=5 D2D Relay,>=50 D2D Multi Hop Relay) numbers of devices as a lower limits.

Metasurfaces are envisaged to play a key role in next-generation wireless systems due to their powerful control over electromagnetic waves. The last decade has witnessed huge advances in this regard, shifting from static to programmable metasurfaces. The HyperSurface (HSF) paradigm takes one step further by integrating a network of controllers within the device with the aim of adding intelligence, connectivity, and autonomy. However, little is known about the traffic that this network will have to support as the target electromagnetic function or boundary conditions change. In this paper, we lay down the foundations of a methodology to characterize the workload of programmable metasurfaces and then employ it to analyze the case of beam steering HSFs. We observe that traffic is bursty and highly dependent on the position of the target. These results will enable the early-stage evaluation of intra-HSF networks, as well as the estimation of the system performance and cost.

In the development of terahertz (THz) communication systems, the nanoantenna is the most significant component. Especially, the focus is to design highly directive antennas, because it enhances the performance of the overall system by compensating the large path loss at THz and thus improves the signal-to-noise ratio. This paper presents suitable material for nanoantenna design and the advancement in their performance for THz communications. Copper, Graphene, and carbon nanotube materials are used as promising candidates for nanoantenna design. The performance of nanoantennas is carried out by analyzing the properties and behavior of the material at THz. Results show that the Graphene nanoantenna provides better performance in terms of miniaturization, directivity, and radiation efficiency. Further, the performance enhancement of the nanoantenna at THz is studied by dynamically adjusting the surface conductivity via the chemical potential of Graphene using the electric field effect. The performance of the nanoantenna is enhanced in terms of high miniaturization, high directivity, low reflection, frequency reconfiguration, and stable impedance. The THz nanoantennas using Graphene have the potential to be used for THz communication systems. In view of the smart THz wireless environment; this paper finally presents a THz Hypersurface using Graphene meta-atoms. The user-side Graphene nanoantennas and environment-side Graphene Hypersurface can build a promising smart THz wireless environment.

HyperSurfaces (HSFs) consist of structurally reconfigurable metasurfaces whose electromagnetic properties can be changed via a software interface, using an embedded miniaturized network of controllers. With the HSF controllers, interconnected in an irregular, near-Manhattan geometry, we propose a robust, deterministic Fault-Tolerant (FT), deadlock- and livelock-free routing protocol where faults are contained in a set of disjointed rectangular regions called faulty blocks. The proposed FT protocol can support an unbounded number of faulty nodes as long as nodes outside the faulty blocks are connected. Simulation results show the efficacy of the proposed FT protocol under various faulty node distribution scenarios.

Intelligent surfaces exert deterministic control over the wireless propagation phenomenon, enabling novel capabilities in performance, security and wireless power transfer. Such surfaces come in the form of rectangular tiles that cascade to cover large surfaces such as walls, ceilings or building facades. Each tile is addressable and can receive software commands from a controller, manipulating an impinging electromagnetic wave upon it by customizing its reflection direction, focus, polarization and phase. A new problem arises concerning the orchestration of a set of tiles towards serving end-to-end communication objectives. Towards that end, we propose a novel intelligent surface networking algorithm based on interpretable neural networks. Tiles are mapped to neural network nodes and any tile line-of-sight connectivity is expressed as a neural network link. Tile wave manipulation functionalities are captured via geometric reflection with virtually rotatable tile surface norm, thus being able to tunable distribute power impinging upon a tile over the corresponding neural network links, with the corresponding power parts acting as the link weights. A feedforward/backpropagate process optimizes these weights to match ideal propagation outcomes (normalized network power outputs) to wireless user emissions (normalized network power inputs). An interpretation process translates these weights to the corresponding tile wave manipulation functionalities., Comment: The article received funding from the EU H2020 FETOPEN-RIA project VISORSURF (EU736876). Published at IEEE Transactions on Communications: https://ieeexplore.ieee.org/document/9151237

Intensive livestock production might have a negative environmental impact, by producing large amounts of animal manure, which, if not properly managed, can contaminate nearby water bodies with nutrient excess. However, if animal manure is exported to nearby crop fields, to be used as organic fertilizer, pollution can be mitigated. It is a single-objective optimization problem, in regards to finding the best solution for the logistics process of satisfying nutrient needs of crops by means of livestock manure. This paper proposes three different approaches to solve the problem: a centralized optimal algorithm (COA), a decentralized nature-inspired cooperative technique, based on the foraging behaviour of ants (AIA), as well as a naive neighbour-based method (NBS), which constitutes the existing practice used today in an ad hoc, uncoordinated manner in Catalonia. Results show that the COA approach is 8.5% more efficient than the AIA. However, the AIA approach is fairer to the farmers and more balanced in terms of average transportation distances that need to be covered by each livestock farmer, while it is 1.07 times more eefficient than the NBS. Our work constitutes the first application of a decentralized AIA to this interesting real-world problem, in a domain where swarm intelligence methods are still under-exploited., Comment: Computers and Electronics in Agriculture Journal. arXiv admin note: substantial text overlap with arXiv:2006.04573

Intensive livestock production might have a negative environmental impact, by producing large amounts of animal excrements, which, if not properly managed, can contaminate nearby water bodies with nutrient excess. However, if animal manure is exported to distant crop fields, to be used as organic fertilizer, pollution can be mitigated. It is a single-objective optimization problem, in regards to finding the best solution for the logistics process of satisfying nutrient crops needs by means of livestock manure. This paper proposes a dynamic approach to solve the problem, based on a decentralized nature-inspired cooperative technique, inspired by the foraging behavior of ants (AIA). Results provide important insights for policy-makers over the potential of using animal manure as fertilizer for crop fields, while AIA solves the problem effectively, in a fair way to the farmers and well balanced in terms of average transportation distances that need to be covered by each livestock farmer. Our work constitutes the first application of a decentralized AIA to this interesting real-world problem, in a domain where swarm intelligence methods are still under-exploited., Comment: Proc. of the XXIVth International Society for Photogrammetry and Remote Sensing (ISPRS) Congress, June 2020

This paper presents illustrative electromagnetic modelling and simulation of graphene antenna using a two-dimensional graphene sheet of zero thickness and a three-dimensional graphene slab of finite thickness. The properties of the antenna are analyzed in terms of the S11 parameter, input impedance, VSWR, radiation pattern, and frequency reconfiguration using the full-wave electromagnetic simulator. Furthermore, this work numerically studies the modelling of graphene antenna using a three-dimensional graphene thin slab and the impact of graphene slab thickness on the performance of graphene antenna.

In this work, we investigated graphene hypersurface (HSF) for the manipulation of THz waves. The graphene HSF structure is consists of a periodic array of graphene unit cells deposited on silicon substrate and terminated by a metallic ground plane. The performance of the proposed HSF is numerically analyzed. Electromagnetic parameters of HSF such as permeability, permittivity, and impedance are studied. The proposed graphene HSF has active control over absorption, reflection, and transmission of THz waves. The graphene HSF provides perfect absorption, zero reflection and zero transmission at resonance. Moreover, the graphene HSF structure has the advantage of anomalous reflection and frequency reconfiguration. Incident waves can be reflected in the desired direction, depending on the phase gradient of the HSF and the perfect absorption is maintained at all reconfigurable frequencies upon reconfiguration. The results reveal the effectiveness of the graphene HSF for the manipulation of THz waves.

Programmable wireless environments (PWEs) utilize electromagnetic metasurfaces to transform wireless propagation into a software-controlled resource. In this work we study the effects of user device mobility on the efficiency of PWEs. An analytical model is proposed, which describes the potential misalignment between user-emitted waves and the active PWE configuration, and can constitute the basis for studying queuing problems in PWEs. Subsequently, a novel, beam steering approach is proposed which can effectively mitigate the misalignment effects. Ray-tracing-based simulations evaluate the proposed scheme., Comment: In proceedings of IEEE ICASSP 2020. This work was funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN-RIA), grant EU736876, project VISORSURF (http://visorsurf.eu)

Device to Device (D2D) Communication is one of the technology components of the evolving 5G architecture, as it promises improvements in energy efficiency, spectral efficiency, overall system capacity, and higher data rates. The above noted improvements in network performance spearheaded a vast amount of research in D2D, which have identified significant challenges that need to be addressed before realizing their full potential in emerging 5G Networks. Towards this end, this paper proposes the use of a distributed intelligent approach to control the generation of D2D networks. More precisely, the proposed approach uses Belief-Desire-Intention (BDI) intelligent agents with extended capabilities (BDIx) to manage each D2D node independently and autonomously, without the help of the Base Station. The paper includes detailed algorithmic description for the decision of transmission mode, which maximizes the data rate, minimizes the power consumptions, while taking into consideration the computational load. Simulations show the applicability of BDI agents in jointly solving D2D challenges., Comment: 10 pages,9 figures

In this work, we investigated a simple structured graphene terahertz (THz) metasurface (MSF) with perfect absorption, wideband, polarization insensitive, oblique incidence insensitive and frequency reconfiguration. The graphene MSF structure is composed of a two-dimensional periodic array of graphene meta-atoms deposited on the silicon substrate terminated by a metal ground plane. The performance of the proposed MSF is numerically analyzed. An equivalent circuit model of the structure and its closed-form solution is introduced. The graphene MSF thin structure at 2.5 THz provides 100% of absorption with wide bandwidth, zero reflection and zero transmission at normal incidence in both transverse electric (TE) and transverse magnetic (TM) polarization. Under oblique incidence, the absorption is maintained at higher than 95%. Moreover, the graphene MSF structure has the advantage of frequency reconfiguration. The excellent absorption performance is maintained at all reconfigurable frequencies upon reconfiguration. The results reveal the effectiveness of the THz MSF with graphene meta-atoms, which can be promising for THz wireless environment., Comment: IEEE MTTW 2019

Software-defined metasurfaces are electromagnetically ultra-thin, artificial components that can provide engineered and externally controllable functionalities. The control over these functionalities is enabled by the metasurface tunability, which is implemented by embedded electronic circuits that modify locally the surface resistance and reactance. Integrating controllers within the metasurface cells, able to intercommunicate and adaptively reconfigure it, thus imparting a desired electromagnetic operation, opens the path towards the creation of an artificially intelligent (AI) fabric where each unit cell can have its own sensing, programmable computing, and actuation facilities. In this work we take a crucial step towards bringing the AI metasurface technology to emerging applications, in particular exploring the wireless mm-wave intercell communication capabilities in a software-defined HyperSurface designed for operation is the microwave regime. We examine three different wireless communication channels within the landscape of the reflective metasurface: Firstly, in the layer where the control electronics of the HyperSurface lie, secondly inside a dedicated layer enclosed between two metallic plates, and, thirdly, inside the metasurface itself. For each case we examine the physical implementation of the mm-wave transponder nodes, we quantify communication channel metrics, and we identify complexity vs. performance trade-offs.

This paper proposes a three-dimensional (3D) communication channel model for an indoor environment considering the effect of the Hypersurface. The Hypersurface is a software controlled intelligent metasurface, which can be used to manipulate electromagnetic waves, as for example for non-specular reflection and full absorption. Thus it can control the impinging rays from a transmitter towards a receiver location in both LOS and NLOS paths, e.g. to combat distance and improve wireless connectivity. We focus on the 60 GHz mmWave frequency band due to its increasing significance in 5G/6G networks and evaluate the effect of Hypersurface in an indoor environment in terms of attenuation coefficients related to the Hypersurface reflection and absorption functionalities, using CST simulation, a 3D electromagnetic simulator of high frequency components. To highlight the benefits of Hypersurface coated walls versus plain walls, we use the derived Hypersurface 3D channel model and a custom 3D ray-tracing simulator for plain walls considering a typical indoor scenario for different Tx-Rx location and separation distances., Comment: Accepted

Software-defined metasurfaces (SDMs) comprise a dense topology of basic elements called meta-atoms, exerting the highest degree of control over surface currents among intelligent panel technologies. As such, they can transform impinging electromagnetic (EM) waves in complex ways, modifying their direction, power, frequency spectrum, polarity and phase. A well-defined software interface allows for applying such functionalities to waves and inter-networking SDMs, while abstracting the underlying physics. A network of SDMs deployed over objects within an area, such as a floorplan walls, creates programmable wireless environments (PWEs) with fully customizable propagation of waves within them. This work studies the use of machine learning for configuring such environments to the benefit of users within. The methodology consists of modeling wireless propagation as a custom, interpretable, back-propagating neural network, with SDM elements as nodes and their cross-interactions as links. Following a training period the network learns the propagation basics of SDMs and configures them to facilitate the communication of users within their vicinity., Comment: In proceedings of IEEE SPAWC 2019 - Special Session on Signal Processing Advances for Emerging Transceiver Hardware. This work was funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN), grant EU736876, project VISORSURF (http://www.visorsurf.eu)

Programmable, intelligent surfaces can manipulate electromagnetic waves impinging upon them, producing arbitrarily shaped reflection, refraction and diffraction, to the benefit of wireless users. Moreover, in their recent form of HyperSurfaces, they have acquired inter-networking capabilities, enabling the Internet of Material Properties with immense potential in wireless communications. However, as with any system with inputs and outputs, accurate sensing of the impinging wave attributes is imperative for programming HyperSurfaces to obtain a required response. Related solutions include field nano-sensors embedded within HyperSurfaces to perform minute measurements over the area of the HyperSurface, as well as external sensing systems. The present work proposes a sensing system that can operate without such additional hardware. The novel scheme programs the HyperSurface to perform compressed sensing of the impinging wave via simple one-antenna power measurements. The HyperSurface can jointly be programmed for both wave sensing and wave manipulation duties at the same time. Evaluation via simulations validates the concept and highlight its promising potential., Comment: Published at IEEE DCOSS 2019 / IoT4.0 workshop (https://www.dcoss.org/workshops.html). Funded by the European Union via the Horizon 2020: Future Emerging Topics - Research and Innovation Action call (FETOPEN-RIA), grant EU736876, project VISORSURF (http://www.visorsurf.eu)

Programmable wireless environments enable the software-defined propagation of waves within them, yielding exceptional performance potential. Several building-block technologies have been implemented and evaluated at the physical layer. The present work contributes a network-layer scheme to configure such environments for multiple users and objectives, and for any physical-layer technology. Supported objectives include any combination of Quality of Service and power transfer optimization, eavesdropping and Doppler effect mitigation, in multi-cast or uni-cast settings. Additionally, a graph-based model of programmable environments is proposed, which incorporates core physical observations and efficiently separates physical and networking concerns. Evaluation takes place in a specially developed, free simulation tool, and in a variety of environments. Performance gains over regular propagation are highlighted, reaching important insights on the user capacity of programmable environments., Comment: This work is part of project VISORSURF: A HyperVisor for Metasurface Functionalities (www.visorsurf.eu). Funded by the European Union Horizon 2020, under the Future Emerging Technologies - Research and Innovation Actions call (Grant Agreement EU 736876)

Wireless communication environments comprise passive objects that cause performance degradation and eavesdropping concerns due to anomalous scattering. This paper proposes a new paradigm, where scattering becomes software-defined and, subsequently, optimizable across wide frequency ranges. Through the proposed programmable wireless environments, the path loss, multi-path fading and interference effects can be controlled and mitigated. Moreover, the eavesdropping can be prevented via novel physical layer security capabilities. The core technology of this new paradigm is the concept of metasurfaces, which are planar intelligent structures whose effects on impinging electromagnetic waves are fully defined by their micro-structure. Their control over impinging waves has been demonstrated to span from 1 GHz to 10 THz. This paper contributes the software-programmable wireless environment, consisting of several HyperSurface tiles (programmable metasurfaces) controlled by a central server. HyperSurfaces are a novel class of metasurfaces whose structure and, hence, electromagnetic behavior can be altered and controlled via a software interface. Multiple networked tiles coat indoor objects, allowing fine-grained, customizable reflection, absorption or polarization overall. A central server calculates and deploys the optimal electromagnetic interaction per tile, to the benefit of communicating devices. Realistic simulations using full 3D ray-tracing demonstrate the groundbreaking performance and security potential of the proposed approach in 2.4 GHz and 60 GHz frequencies., Comment: This work was partially funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN), grant EU736876, project VISORSURF. admin note: significant overlap with arXiv:1805.06677

HyperSurfaces are a merge of structurally reconfigurable metasurfaces whose electromagnetic properties can be changed via a software interface, using an embedded miniaturized network of controllers, thus enabling novel capabilities in wireless communications. Resource constraints associated with the development of a hardware testbed of this breakthrough technology necessitate network controller architectures different from traditional regular Network-on-Chip architectures. The Manhattan-like topology chosen to realize the controller network in the testbed under development is irregular, with restricted local path selection options, operating in an asynchronous fashion. These characteristics render traditional fault-tolerant routing mechanisms inadequate. In this paper, we present work in progress towards the development of fault-tolerant routing mechanisms for the chosen architecture. We present two XY-based approaches which have been developed aiming to offer reliable data delivery in the presence of faults. The first approach aims to avoid loops while the second one attempts to maximize the success delivery probabilities. Their effectiveness is demonstrated via simulations conducted on a custom developed simulator., Comment: 6 pages, 8 figures, conference

A metasurface is a surface that consists of artificial material, called metamaterial, with configurable electromagnetic properties. This paper presents work in progress on the design and formal verification of a programmable metasurface, the Hypersurface, as part of the requirements of the VISORSURF research program (HORIZON 2020 FET-OPEN). The Hypersurface design is concerned with the development of a network of switch controllers that are responsible for configuring the metamaterial. The design of the Hypersurface, however, has demanding requirements that need to be delivered within a context of limited resources. This paper shares the experience of a rigorous design procedure for the Hypersurface network, that involves iterations between designing a network and its protocols and the formal evaluation of each design. Formal evaluation has provided results that, so far, drive the development team in a more robust design and overall aid in reducing the cost of the Hypersurface manufacturing. This paper presents work in progress on the design and formal verification of a programmable Hypersurface as part of the requirements of the VISORSURF research programme (HORIZON 2020 FET-OPEN)., Comment: 13 pages. The paper has been accepted at FMICS 2018 and will be published by Springer

This article introduces an approach that could tame wireless channels, making their behavior deterministic and software-defined. We investigate the novel idea of HyperSurfaces, which are software-controlled metamaterials embedded in any surface in the environment. HyperSurfaces are materials that interact with electromagnetic waves in a fully software-defined fashion, even unnaturally. Coating walls, doors, furniture and other objects with HyperSurfaces constitutes the overall behavior of an indoor wireless environment programmable. Thus, the electromagnetic behavior of the environment as a whole can be controlled and tailored to the needs of mobile devices within it., Comment: Paper accepted as viewpoint article in Communications of the ACM. (Accepted on 1-Mar-2018). This work was funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN-RIA), grant EU736876, project VISORSURF: HyperSurfaces-A Hardware Platform for Software-driven Functional Metasurfaces (http://www.visorsurf.eu/)

Electromagnetic waves undergo multiple uncontrollable alterations as they propagate within a wireless environment. Free space path loss, signal absorption, as well as reflections, refractions and diffractions caused by physical objects within the environment highly affect the performance of wireless communications. Currently, such effects are intractable to account for and are treated as probabilistic factors. The paper proposes a radically different approach, enabling deterministic, programmable control over the behavior of the wireless environments. The key-enabler is the so-called HyperSurface tile, a novel class of planar meta-materials which can interact with impinging electromagnetic waves in a controlled manner. The HyperSurface tiles can effectively re-engineer electromagnetic waves, including steering towards any desired direction, full absorption, polarization manipulation and more. Multiple tiles are employed to coat objects such as walls, furniture, overall, any objects in the indoor and outdoor environments. An external software service calculates and deploys the optimal interaction types per tile, to best fit the needs of communicating devices. Evaluation via simulations highlights the potential of the new concept., Comment: Paper accepted for publication at the IEEE Communications Magazine. This work was funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN-RIA), grant EU736876, project VISORSURF: HyperSurfaces-A Hardware Platform for Software-driven Functional Metasurfaces (http://www.visorsurf.eu/)

Wireless communication environments are unaware of the ongoing data exchange efforts within them. Moreover, their effect on the communication quality is intractable in all but the simplest cases. The present work proposes a new paradigm, where indoor scattering becomes software-defined and, subsequently, optimizable across wide frequency ranges. Moreover, the controlled scattering can surpass natural behavior, exemplary overriding Snell's law, reflecting waves towards any custom angle (including negative ones). Thus, path loss and multi-path fading effects can be controlled and mitigated. The core technology of this new paradigm are metasurfaces, planar artificial structures whose effect on impinging electromagnetic waves is fully defined by their macro-structure. The present study contributes the software-programmable wireless environment model, consisting of several HyperSurface tiles controlled by a central, environment configuration server. HyperSurfaces are a novel class of metasurfaces whose structure and, hence, electromagnetic behavior can be altered and controlled via a software interface. Multiple networked tiles coat indoor objects, allowing fine-grained, customizable reflection, absorption or polarization overall. A central server calculates and deploys the optimal electromagnetic interaction per tile, to the benefit of communicating devices. Realistic simulations using full 3D ray-tracing demonstrate the groundbreaking potential of the proposed approach in 2.4 GHz and 60 GHz frequencies., Comment: This paper appears at the 19TH IEEE WOWMOM 2018, JUNE 12-15, 2018. (Technical program: http://it.murdoch.edu.au/wowmom2018/technical_program.html) This work was funded by the European Union via the Horizon 2020: Future Emerging Topics call (FETOPEN-RIA), grant EU736876, project VISORSURF (http://www.visorsurf.eu) : HyperSurfaces-A Hardware Platform for Software-driven Functional Metasurfaces

We consider nanonodes randomly distributed in a circular area and characterize the received signal strength when a pair of these nodes employ molecular communication. Two communication methods are investigated, namely free diffusion and diffusion with drift. Since the nodes are randomly distributed, the distance between them can be represented as a random variable, which results in a stochastic process representation of the received signal strength. We derive the probability density function of this process for both molecular communication methods. Specifically for the case of free diffusion we also derive the cumulative distribution function, which can be used to derive transmission success probabilities. The presented work constitutes a first step towards the characterization of the signal to noise ratio in the considered setting for a number of molecular communication methods., Comment: 6 pages, 6 figures, Nanocom 2017 conference

A recently proposed class of materials, called software-defined metamaterials, can change their electromagnetic behavior on demand, utilizing a nanonetwork embedded in their structure. The present work focuses on 2D metamaterials, known as metasurfaces, and their electromagnetically programmable counterparts, the HyperSurfaces. The particular focus of the study is to propose a nanonetworking protocol that can support the intended macroscopic functionality of a HyperSurface, such as sensing and reacting to impinging waves in a customizable manner. The novel protocol is derived analytically, using the Lyapunov drift minimization approach, taking into account nano-node energy, communication latency and complexity concerns. The proposed scheme is evaluated via simulations, covering both the macroscopic HyperSurface functionality and the microscopic, nanonetwork behavior.