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 ...
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 ...
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 ...
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 ...
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. ...
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.
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 ...
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 ...
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 ...
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 ...
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 ...
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. ...
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.
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 ...
Uploads
Papers by Pietro Savazzi