Claudia Rinaldi

Performance Analysis and Optimization of TCP over Adaptive Wireless Links

This paper proposes an analytical framework for performance evaluation of TCP (transport control protocol) over adaptive wireless links. Specifically, we include adaptation of power, modulation format and error recovery strategy, and incorporate some features of wireless fading channels. This framework is then used to pursue joint optimization through maximization of an objective functional, that expresses a trade-off between achievable throughput and energy costs. A set of numerical results is reported, and it is seen that hybrid ARQ schemes may provide significant benefits in the optimization framework

Exploiting WSN for Audio Surveillance Applications: The VoWSN Approach

This paper focuses on the analysis of fundamental issues which has to be considered in order to gain voice from a wireless sensor network (WSN) that is assumed to be constituted by MicaZ wireless sensor nodes. Problems related to the transport of an audio signal through a wireless channel and sensor nodes are thus analyzed and a project for an audio surveillance system is presented.

Performance evaluation of UWB signaling at mmWaves

Ultra-wideband (UWB) radios have the potential to achieve very high data rates. However, the coverage is limited over very short ranges, due to the tight limits imposed to the allowed transmission power by the worldwide spectrum regulation at microWaves. Recently, a very large bandwidth has been made available by worldwide regulation at mmWaves. Wide consensus is achieved on the future utilization of the spectral region around 60 GHz for multi-Gbps wireless LAN connectivity. Given the availability of a very large band, up to 7 GHz, mmWaves appear as the natural candidate for UWB transmissions. The aim of this paper is to evaluate the performance of impulse radio (IR)-UWB signalling when operating at mmWaves, i.e., around 60 GHz. The analysis is based on a semi-analytical approach, where the bit error rate (BER) for pulse position modulation (PPM) and pulse amplitude modulation (PAM) is analytically computed and averaged over the empirical probability density function of the signal-to-noise-ratio (SNR) as obtained from a significant set of experimental impulse responses of the UWB indoor channel at mmWaves. These channel impulse responses have been collected through a measurement campaign in a modern office building at eight carrier frequencies spanning the band from 54 to 59 GHz and from 61 to 66 GHz. The results show a promising potential for mmWaves UWB radios.

Performance analysis of a lightweight RSSI-based localization algorithm for Wireless Sensor Networks

Localization systems based on Wireless Sensor Networks (WSNs) have become very popular in recent years and location-awareness is a critical step for upcoming applications and communication systems. This paper presents a new localization algorithm through WSNs, which is based on Received Signal Strength (RSS) measurements. Although the localization accuracy obtained is comparable with existing literature algorithms, the proposed technique proves to be of practical implementation on devices with low computational capabilities as well as efficient in real-time usages. We verified such properties and investigated reachable precision through extensive experimental measurements on indoor and outdoor controlled scenarios, as well as on the real scenario offered by a flat equipped with domotic facilities to increase autonomy of people affected by disabilities.

Short range wireless solutions enabling ambient assisted living to support people affected by the Down syndrome

Assistive technologies can provide solutions to people with physical disabilities or to weaker individuals that need particular attention. As a branch of assistive technologies, ambient care systems are emerging. In this paper we present an overall domotic architecture that, supported by a Wireless Sensor Network (WSN) and the use of heterogeneous devices, aims to provide multiple interfaces between a smart house and its guests. In particular we describe the results applied in the project Casa+, a smart house that is addressed to people with Down syndrome; it offers functionalities for monitoring the environment and its guests, giving indication signals, audio messages or even alarms in case of incorrect actions. Through exploitation of the most recent technologies, keeping in mind the trade off with costs, we developed the following functionalities: security, time management, assistance for daily activities, monitoring and remote control, tracking.

WSN-Based Audio Surveillance Systems

This work focuses on the analysis of fundamental issues which have to be considered in order to obtain voice from a wireless sensor network (WSN). The latter is assumed to be constituted by MicaZ wireless sensor nodes. Problems related to the transport of an audio signal through a wireless channel and sensor nodes are thus analyzed, and a project for an audio surveillance system is presented.

Mining ventilation automation: Wireless sensing, communication architecture and advanced services

This paper reports on the definition of technical challenges for the sensing and communication networks of a mining ventilation automation project. Specifically, complex network architectures offering high performance are investigated. The aim is to support distributed estimation, and to propose an enhanced architecture for advanced services in the mining context, namely positioning and audio/video communications. Then, analytical models are developed to ldquoexposerdquo network performance to the control application, and a service platform is suggested to encapsulate all essential services that the network should provide to the distributed control application. Specific results are provided for the positioning service.

Hybrid Model of Least Squares Handover Algorithms in Wireless Networks

An adaptive handover algorithm for wireless communication systems is addressed in this paper. Moving from the Generalized Extended Least Square handover algorithm proposed in N. Benvenuto et al. (2002), we model the handover mechanism as a hybrid system, and we include it in a dynamic optimization problem which is solved through the use of a trellis diagram. The objective function takes into account the parameters that influence the handover mechanism. The optimal solution of the program allows to evaluate performance of the handover in terms of the probability of handover and probability of outage.

Performance analysis of a lightweight localization algorithm for WSNs in a real scenario

Indoor range-based localization algorithms often require a noticeable computational effort and, even providing a good precision, cannot always fit on a limited-resource device of a Wireless Sensor Network (WSN). This paper proceeds a previous work that has investigated the reachable precision of a lightweight localization based on Received Signal Strength (RSS). This time the focus is put on a real implementation on the nodes of a WSN running a concrete Operating System and executing application tasks. Implementation issues are put in evidence, experimental measurement in indoor and outdoor scenarios are performed and some limitations of the proposed technique are outlined.

Advanced Solutions to Support Daily Life of People Affected by the Down Syndrome

Recent technologies applied or explicitly developed for assisting people with physical disabilities or weaker individuals needing particular attention, are becoming an emerging research topic. In this paper we focus on ambient care systems and we present an overall architecture that aims to provide multiple interfaces between a smart house and its guests. In particular we describe the results applied in the project Casa + , a smart house that is addressed to people with Down syndrome; it offers functionalities for monitoring the environment and its guests, giving indication signals, audio messages or even alarms in case of incorrect actions. Through exploitation of the most recent technologies, keeping in mind the trade off with costs, we developed the following functionalities: security, time management, assistance for daily activities, monitoring and remote control, outdoor tracking.