Pietro Savazzi | University of Pavia (original) (raw)

Papers by Pietro Savazzi

MATLAB Simulator of passive RFID EPC G2 C1 tags

Intra-body communication (IBC) is a novel research filed that will promote personalized medicine ... more Intra-body communication (IBC) is a novel research filed that will promote personalized medicine by allowing real time and in situ monitoring in daily life. In this work, the energy efficient galvanic coupling (GC) technology is used to send electromyography (EMG) data through intra-body links. Real EMG data are first acquired and recorded with needle electrodes inserted in the muscle of a person's forearm. Then, the data are transferred via GC communication employing a GC sound card-based testbed. The experiments are conducted by transferring EMG data in both ex-vivo and in-vivo tissue with different electrodes placements. Almost error free performance is achieved with a robust and reliable communication, a valuable result in medical applications. Index Terms-Intra-body networks, intra-body communication, galvanic coupling technology, coupling circuits, wireless sensor network, biomedical engineering, biomedical electronics, experimental testbed. Anna Vizziello (M'09-SM'20) received the Laurea degree in electronic engineering and the Ph.D. degree in electronics and computer science from the

Since its discovery in 1881, Benford's law has been verified in several application fields relate... more Since its discovery in 1881, Benford's law has been verified in several application fields related to economics, physics and even in number theory. In particular, a random dataset obtained from physical measurements seems to be the best empirical example of its validity. Following this reasoning, we present a novel and fast source coding algorithm for wireless sensor measurements. In more details, the Benford's probability density distribution is exploited for Huffmann coding of measured values, considering the Benford probability density of the first digit. This results may be fast obtained assuming the Benford's law validity, without directly computing the a priori probabilities of the measured digits. Performance evaluation is provided by system simulations, comparing the obtained results with the computed a posteriori source entropy.

IEEE Transactions on Magnetics, 2010

A recent work presents a regressive noise model for the data-dependent correlated noise, at the o... more A recent work presents a regressive noise model for the data-dependent correlated noise, at the output of a magnetic recording channel detector. This paper generalizes this channel model, considering digital equalization and a more efficient correlation matrix, in order to make a comparison with the usual detector in a more realistic environment. Simulation results show that the regressive detector performs better when the number of trellis states is lower than needed, while both approaches are comparable when the number of states matches the channel memory.

Springer eBooks, 1999

Summary In this work a fuzzy version of the Connectivity Weighted Hough Transform (CWHT) is used ... more Summary In this work a fuzzy version of the Connectivity Weighted Hough Transform (CWHT) is used to detect streets and roads in high resolution (synthetic Aperture Radar (SAR) images of urban environments. The basic idea is to define a pyramidal procedure suitable for the characterization of several types of streets having different width. In this sense a modified Hough Transform, based on results produced by fuzzy clustering techniques, is introduced to group pixels classified as possible roads in consistent straight ...

Abstract In this work, the fuzzy-c-means (FCM) clustering algorithm is used to achieve joint equa... more Abstract In this work, the fuzzy-c-means (FCM) clustering algorithm is used to achieve joint equalization and demodulation of a QAM signal affected by intersymbol interference (ISI) in a blind mode, ie without insertion of a training sequence in the data stream. The points of the constellation are the cluster centers and are adapted to the current channel estimate iteratively by minimizing the FCM function. The clustering process takes place at every information packet and groups the received complex symbols by similarity without ...

IEEE Vehicular Technology Conference, Apr 1, 2007

Abstract Cell sectorization is a common approach used in cellular systems to increase system capa... more Abstract Cell sectorization is a common approach used in cellular systems to increase system capacity. In this paper a novel approach to downlink spatial filtering based on clustering algorithms is proposed for UMTS-FDD cellular networks. In more details, the well known segmentation algorithm K-means is applied for grouping users in order to define the spatial beams. It is assumed that the direction of arrival of received uplink channels known at the base-station. The ability of the proposed automated scheme is evaluated by ...

Computer Networks, May 1, 2023

The Internet of Medical Things (IoMT) paradigm will enable next generation healthcare by enhancin... more The Internet of Medical Things (IoMT) paradigm will enable next generation healthcare by enhancing human abilities, supporting continuous body monitoring and restoring lost physiological functions due to serious impairments. This paper presents intra-body communication solutions that interconnect implantable devices for application to the nervous system, challenging the specific features of the complex intra-body scenario. The presented approaches include both speculative and implementative methods, ranging from neural signal transmission to testbeds, to be applied to specific neural diseases therapies. Also future directions in this research area are considered to overcome the existing technical challenges mainly associated with miniaturization, power supply, and multi-scale communications.

IEEE Communications Magazine, Aug 1, 2022

Wireless sensor networks based on passive sensing can be successfully employed on spacecrafts, in... more Wireless sensor networks based on passive sensing can be successfully employed on spacecrafts, in both ground test campaign and in-flight monitoring. This work investigates the operation of the wireless sensors system within the actual environment in terms of link budget of the radio frequency (RF) channel under the Electromagnetic Compatibility (EMC) constraints. For this purpose two different frequency division multiplexing (FDM) systems have been considered, both operating in different isolated cavities in order to allow frequency reuse. A complete characterization of the wireless system proves the technology feasibility, taking into accounts both the link budget analysis results and the EMC specifications to be followed in space applications.

Abstract In this work, two ways of generating soft-bit received sequences are proposed. In partic... more Abstract In this work, two ways of generating soft-bit received sequences are proposed. In particular, chaos based models and hidden Markov models, which have been well used in recent years to build hard generative error sequences, are trained by soft-bit sequences sampled at the output of a link level simulator of a GSM-GPRS transceiver. Modern wireless standards make use of inner codes, like convolutional or turbo ones, that perform better with soft decision decoding techniques than with hard ones. For this reason, a fast generative ...

EURASIP Journal on Embedded Systems, May 4, 2016

Ultra-wideband (UWB) technology is foreseen as a promising solution to overcome the limits of ult... more Ultra-wideband (UWB) technology is foreseen as a promising solution to overcome the limits of ultra-high frequency (UHF) techniques toward the development of green radio frequency identification (RFID) systems with low energy consumption and localization capabilities. While UWB techniques have been already employed for active tags, passive tags solutions are more appealing also due to their lower cost. With the fundamental requirement of maintaining backward compatibility in the RFID domain, we propose a hybrid UWB/UHF architecture to improve passive tag identification both in single-reader and multi-reader scenarios. We then develop two hybrid algorithms: the first one exploits the UWB signal to improve ISO/IEC 18000-6C UHF standard, while the other one exploits UWB to enhance a compressive sensing (CS) technique for tag identification in the multi-reader, multi-tag scenario. Both solutions are able to improve success rate and reading speed in the tag identification process and reduce the energy consumption. The multi-reader version of the proposed approaches is based on a cooperative scheme in order to manage reader-tag collisions and reader-reader collisions besides the typical tag-tag collisions. Furthermore, timing synchronization non-idealities are analyzed for the proposed solutions and simulation results reveal the effectiveness of the developed schemes.

IEEE Access, 2020

Intra-body communication (IBC) is a novel key research area that will foster personalized medicin... more Intra-body communication (IBC) is a novel key research area that will foster personalized medicine by allowing in situ and real time monitoring in daily life. In this work, the energy efficient galvanic coupling (GC) technology is used to send data through intra-body links. A novel sound card-based GC testbed is designed and implemented, whose main features are: (i) low equipment requirements since it only employs two ordinary PCs with sound card support and Matlab software, (ii) high flexibility since all the parameters setting may be easily modified through the PC control panel and Matlab programs, (iii) real time physiological data transmissions, and (iv) almost error free communication by developing specific physical (PHY) layer techniques, which are implemented and tested with a real chicken tissue in the experimental evaluation. A signal to noise ratio (SNR) calculation is also proposed with the twofold purpose to be used for frequency offset compensation and as metric to evaluate the proposed architecture. The developed GC testbed may be easily replicated by the interested research community to carry out simulation-based experiments, thus fostering new research in this field. Moreover, the Matlab source code of the proposed GC transceiver is freely available online on Code Ocean.

IEEE Communications Letters, Mar 1, 1999

A novel approach to model mobile radio channels (in particular, DECT ones) is introduced, using n... more A novel approach to model mobile radio channels (in particular, DECT ones) is introduced, using nonlinear equations proposed by chaos theory. A simple procedure to extract meaningful statistics from strange attractors' trajectories is presented, and some results well matched with those obtained by standard generative models are shown. Although introducing a quasideterministic behavior, the chaotic equations seem to be sufficient to mimic the apparently random error patterns exhibited by mobile radio channels. An initial attempt is made to sketch guidelines for selecting the chaotic parameters.

Abstract In this work a new classification algorithm that uses FNP mixed with a pyramidal approac... more Abstract In this work a new classification algorithm that uses FNP mixed with a pyramidal approach is proposed. The prototypes of each class are generated by means of FCM with a FNP initialization. The aim of the work is to improve the performances of the usual non parametric classifiers by extracting the maximum information from the training pixels and from the pixels to be classified. This is done by using both the high spatial-correlation between pixels and the confidence levels, given by the fuzzy algorithm. Results are ...

IEEE Vehicular Technology Conference, Sep 1, 2007

Abstract This paper presents a joint symbol timing recovery and equalization scheme for short bur... more Abstract This paper presents a joint symbol timing recovery and equalization scheme for short burst transmission formats, useful in modern wireless systems, like, for instance, time-division multiple access schemes and future wireless packet data networks. Both data aided and decision directed solutions are considered and the joint optimization performance is pursued by means of an iterative scheme which exploits a timing error function sampled at symbol rate, implemented by means of the Farrow structure for the interpolation filter. ...

IEEE Access, 2018

Millimeter-wave communication in the 60-GHz band requires large antenna arrays at both the transm... more Millimeter-wave communication in the 60-GHz band requires large antenna arrays at both the transmit and receive terminals to achieve beamforming gains, in order to counteract the high pathloss. Fully digital techniques are infeasible with large antenna arrays due to hardware constraints at such frequencies, while purely analog solutions suffer severe performance limitations. Hybrid analog/digital beamforming is a promising solution, especially, when extended to a multiuser scenario. This paper conveys three main contributions: 1) a Kalman-based formulation for hybrid analog/digital precoding in multiuser environment is proposed; 2) an analytical expression of the error between the transmitted and estimated data is formulated, so that the Kalman algorithm at the base station does not require information on the estimated data at the mobile stations, and instead, relies only on the precoding/combining matrix; and 3) an iterative solution is designed for the hybrid precoding scheme with affordable complexity. Simulation results confirm significant improvement of the proposed approach in terms of both bit error rate and spectral efficiency-achieving almost 7 b/s/Hz, at 20 dB with 10 channel paths with respect to the analog-only beamsteering, and almost 1 b/s/Hz with respect to the hybrid minimum mean square error precoding under the same conditions. INDEX TERMS Hybrid beamforming, Kalman filter, millimiter wave, massive MIMO.

Deep space communications could be advantageously accomplished by using distributed multiple-inpu... more Deep space communications could be advantageously accomplished by using distributed multiple-input, multiple-output (DMIMO) satellite links, as it has been outlined in the recent literature. One of the most critical issues is related to synchronizing both the carrier phase and frequency, affected by Doppler shift and frequency offset at local oscillators. In this work a solution for intermittent carrier and phase synchronization is proposed, considering a baseband scheme which is suitable for both software defined radio (SDR) platforms and hybrid analog-digital higher data rate systems.

IEEE Sensors Journal, Nov 1, 2014

This work is devoted to the feasibility study of a wireless sensing system, mainly based on passi... more This work is devoted to the feasibility study of a wireless sensing system, mainly based on passive surface acoustic wave (SAW) sensors, for remote measurement of temperature aboard space platforms. The use of passive sensors is particularly attractive since they need no battery and are robust in extreme environments, as they contain no active electronic circuits. The main objective of this study is the complete characterization of the wireless system environment, in order to determine the main fundamental limits of this technology from a communication theory point of view. Preliminary experimental measurements are used for both defining the main environment parameters, validating some of the theoretical limit computations and proving the space application feasibility.

Abstract Soft decision decoding algorithms are widely used in modern wireless systems; convolutio... more Abstract Soft decision decoding algorithms are widely used in modern wireless systems; convolutional and turbo codes are usually adopted as the inner scheme thanks to their capability to correct symbol errors at low SNR values. Such algorithms can achieve high coding gains using soft decoding, and modern digital hardware technology enables efficient and low cost practical implementations. We apply the experience gained in previous work, concerning the simulation of bit error processes (Costamagna, E. et al., Proc. IEEE, vol. 90 ...