Igor Bisio

A survey of architectures and scenarios in satellite‐based wireless sensor networks: system design aspects

This paper is not a survey related to generic wireless sensor networks (WSNs), which have been largely treated in a number of survey papers addressing more focused issues; rather, it specifically addresses architectural aspects related to WSNs in some way connected with a satellite link, a topic that presents challenging interworking aspects. The main objective is to provide an overview of the potential role of a satellite segment in future WSNs. In this perspective, requirements of the most meaningful WSN applications have been drawn and matched to characteristics of various satellite/space systems in order to identify suitable integrated configurations. Copyright

Contact graph routing in DTN space networks: overview, enhancements and performance

Delay- and Disruption Tolerant Networks (DTNs) are based on an overlay protocol and on the store-carry-forward paradigm. In practice, each DTN node can store information for a long time before forwarding it. DTNs are particularly suited to cope with the challenges imposed by the space environment. This paper is focused on routing in space DTNs, and in particular on contact graph routing (CGR) and its most representative enhancements, available in the literature, which are briefly surveyed in this work. Moreover, the applicability and the obtained performance of the DTN protocol stack and of the CGR have been evaluated by presenting results from real experimental experiences such as the Deep Impact Network experiment (employing the EPOXI space cruise), the JAXA jointly performed space link demonstrations with NASA (where the JAXAs GEO relay satellite called Data Relay Test Satellite has been used), the Space Data Routers European Project, and the pilot operation of a DTN implementation on the International Space Station (ISS).

A Trainingless WiFi Fingerprint Positioning Approach Over Mobile Devices

Indoor localization of targets by using electromagnetic waves has attracted a lot of attention in the last few years. Thanks to the wide availability of electromagnetic sources deployed for various applications (e.g., WiFi), nowadays it is possible to perform this task by using low-cost mobile devices, such as smartphones. To this end, in order to achieve high positioning accuracy and reduce the computational resources used in the position estimation, fingerprinting approaches are usually employed. However, in this case, a time-consuming training phase, where a great number of measurements must be performed, is needed. In this letter, a novel approach, where the training data are obtained by means of finite-difference time-domain (FDTD) simulations of the electromagnetic propagation in the considered scenario, is presented. The performances of the method are assessed by means of experimental results in a real scenario.

Congestion Aware Routing Strategies for DTN-Based Interplanetary Networks

The networking and communication challenges posed by interplanetary environments make the design and the deployment of complex telecommunication infrastructures particularly difficult, especially with regard to routing and congestion control issues. To this end, the paper proposes a congestion-aware routing paradigm that applies multi attribute decision making (MADM) concepts for next-hop selection, by formulating an optimisation problem and proposing some possible resolution criteria. Effectiveness of the proposed solutions is assessed through a preliminary performance analysis that shows promising results.

Power Saving Bandwidth Allocation over GEO Satellite Networks

The problem of bandwidth allocation may be simply stated, independently of the target of the allocation: an amount of bandwidth must be shared among different entities. Each entity receives a portion of the overall bandwidth. Bandwidth allocation may be formalized as a Multi-Objective Programming (MOP) problem where the constraint is the maximum available bandwidth. The objectives of the allocation such as loss and power may be modelled through a group of objective functions possibly contrasting with each other. It is quite intuitive that using more bandwidth will reduce losses, but also that transmitted power will increase with the bandwidth. Which is the balance among these needs? This letter proposes an extended model for bandwidth allocation [1] and uses a modified version of a MOP-based bandwidth allocation to provide a possible solution to the mentioned balancing problems.

Satellite Communications Supporting Internet of Remote Things

This paper focuses on the use of satellite communication systems for the support of Internet of Things (IoT). We refer to the IoT paradigm as the means to collect data from sensors or RFID and to send control messages to actuators. In many application scenarios, sensors and actuators are distributed over a very wide area; in some cases, they are located in remote areas where they are not served by terrestrial access networks and, as a consequence, the use of satellite communication systems becomes of paramount importance for the Internet of Remote Things (IoRT). The enabling factors of IoRT through satellite are: 1) the interoperability between satellite systems and sensors/actuators and 2) the support of IPv6 over satellite. Furthermore, radio resource management algorithms are required to enhance the efficiency of IoT over satellite. In this work, we provide an integrated view of satellite-based IoT, handling this topic as a jigsaw puzzle where the pieces to be assembled are represented by the following topics: MAC protocols for satellite routed sensor networks, efficient IPv6 support, heterogeneous networks interoperability, quality of service (QoS) management, and group-based communications.

Gender-Driven Emotion Recognition Through Speech Signals For Ambient Intelligence Applications

This paper proposes a system that allows recognizing a persons emotional state starting from audio signal registrations. The provided solution is aimed at improving the interaction among humans and computers, thus allowing effective human-computer intelligent interaction. The system is able to recognize six emotions(anger, boredom, disgust, fear, happiness, and sadness) and the neutral state. This set of emotional states is widely used for emotion recognition purposes. It also distinguishes a single emotion versus all the other possible ones, as proven in the proposed numerical results. The system is composed of two subsystems: 1) gender recognition(GR) and 2) emotion recognition(ER). The experimental analysis shows the performance in terms of accuracy of the proposed ER system. The results highlight that the a priori knowledge of the speakers gender allows a performance increase. The obtained results show also that the features selection adoption assures a satisfying recognition rate and allows reducing the employed features. Future developments of the proposed solution may include the implementation of this system over mobile devices such as smartphones.

Analytical expression and performance evaluation of TCP packet loss probability over geostationary satellite

The letter contains the formulation of an analytical expression of the Transmission Control Protocol (TCP) packet loss probability over geostationary satellite channels on the basis of the state-of-the-art in the field. The expression obtained is function of the bandwidth available and is suited to be used in control mechanisms. It is compared with the results obtained through a satellite network emulator already validated in the literature.

Smartphone-centric ambient assisted living platform for patients suffering from co-morbidities monitoring

Recently, patients suffering from a set of physical and mental limitations, called co-morbidities, are often treated at home. In this environment, modern communication systems represent a great support to implement Ambient Assisted Living platforms aimed at monitoring patients at home because they enable the seamless integration of heterogeneous sensing units, medical devices, and ubiquitous access to data. This article describes a specific smartphone-centric architecture where smartphones are employed not only as hubs of the health information but also as sensing, processing, and transmitting devices. Smartphones have both short-range (Bluetooth and WiFi employed for local information exchange) and long-range (GPRS, 3G/4G, and WiFi employed as Internet access) communication capabilities; information processing capabilities offered by modern platforms often equipped with different CPUs and with flexible and efficient software; and sensing capabilities implemented through sensors embedded into smartphones such as GPS receivers, accelerometers, microphones, and radio interfaces or through external sensors added to smartphones by cables or connected through local radio interfaces. The specific case of co-morbidities considered in this article implies the necessity to acquire a heterogeneous set of data from patients and from their environment. For this reason this article highlights the information processing capabilities of the introduced smartphone-centric platform. Audio, localization, and movement information processing have been evidenced as well as the specific implementations of these capabilities and their performance.

Efficient Satellite-Based Sensor Networks for Information Retrieval

This paper considers a packet-based telecommunication network architecture suited to be used as an Environmental Monitoring System (EMS) over wide areas. It can be employed to retrieve the measures of physical quantities, such as temperature, humidity, and vibrations intensity (physical information) together with the geographical position where the measures are taken (position information). The telecommunication network supporting the EMS is composed of: a network of sensors, a group of earth stations called Sinks, a satellite backbone, and a destination. Each sensor collects physical and position information, encapsulates it into packets and conveys it towards the sinks which give access to the satellite backbone that connects the sinks to the destination. A single sensor transmits the information to all sinks but only one sink transmits it over the satellite channel. Even if the redundant transmission of the same data from more than one sink would increase the safety of the system, it would increase also the costs of it. The selection of the sink which forwards the information of a sensor to the destination is important to increase the performance of the EMS. This paper introduces specific performance metrics to evaluate the functionality of the whole EMS in terms of reliability, reactivity, and spent energy. The reference metrics are packet loss rate, average packet delay, and energy consumption. Then the paper presents an algorithm to select the transmitting sink for each sensor, which is aimed at maximizing the performance in terms of the mentioned metrics. The algorithm is tested through simulation.