Francescantonio Della Rosa

Cooperative Positioning Techniques for Mobile Localization in 4G Cellular Networks

In this paper, we exploit the concept of cooperative localization by utilizing the additional information obtained from short-range links to enhance the location estimation accuracy in forthcoming cellular systems. Simulations for a hybrid WiMAX/Wi-Fi system are carried out considering an outdoor environment, where time difference of arrival (TDOA) and received signal strength (RSS) measurements are combined thanks to advanced data fusion techniques. Results show that the proposed system allows to meet the federal Communications Commission (FCC) requirements and overcome the ever changing channel conditions.

Hand-grip and body-loss impact on RSS measurements for localization of mass market devices

In this paper we present the effect of the hand-grip and the presence of the human body on received signal strength measurements when performing positioning of mass market devices in indoor environments. We demonstrate that the mitigation of both human body and hand-grip influence can enhance the positioning accuracy and that the human factor cannot be neglected in experimental activities with real mobile devices.

Human-Induced Effects on RSS Ranging Measurements for Cooperative Positioning

We present experimental evaluations of human-induced perturbations on received-signal-strength-(RSS-) based ranging measurements for cooperative mobile positioning. To the best of our knowledge, this work is the first attempt to gain insight and understand the impact of both body loss and hand grip on the RSS for enhancing proximity measurements among neighbouring devices in cooperative scenarios. Our main contribution is represented by experimental investigations. Analysis of the errors introduced in the distance estimation using path-loss-based methods has been carried out. Moreover, the exploitation of human-induced perturbations for enhancing the final positioning accuracy through cooperative schemes has been assessed. It has been proved that the effect of cooperation is very limited if human factors are not taken into account when performing experimental activities.

Ad-hoc networks aiding indoor calibrations of heterogeneous devices for Fingerprinting applications

In this paper we propose a Collaborative Mapping (CM) method based on the exploitation of the WLAN Received Signal Strength (RSS) measured from short-range ad-hoc links between neighboring devices. The estimated spatial proximity allows on-the-fly calibrations of heterogeneous clients for Location Fingerprinting (LF) applications. This method can avoid long time-consuming and battery-draining calibrations when implementing Fingerprinting Location applications running on heterogeneous mass market devices.

Experimental Activity on Cooperative Mobile Positioning in Indoor Environments

Traditional localization systems are based on the information obtained from some fixed reference points (e.g., Access Points (APs)) to Mobile Station (MS) links; typically for short-range, Received Signal Strength Difference (RSSD) or Received Signal Strength (RSS) measurements are used. In order to enhance the accuracy of localization systems indoors, the innovative solution presented in this paper considers also the information obtained from MS-MS links. A proof of concept in a real scenario is implemented in an indoor environment by using a Wireless Local Area Network (WLAN), and the results show that the accuracy is enhanced with respect to non-cooperative schemes. Non-Linear Least Square (NLLS) and Extended Kalman Filter (EKF) are used as data fusion algorithms to combine RSSD measurements from AP-MS links and RSS measurements from MS-MS links.

A cooperative framework for path loss calibration and indoor mobile positioning

In this paper, we propose a solution for avoiding extensive time consuming path loss calibrations when performing RSS-to-distance conversions for indoor mobile positioning with heterogeneous mobiles. By exploiting RSS measurements and ad-hoc link communications we prove the concept of cooperative calibration and demonstrate it in a WLAN 802.11 network. Moreover the results obtained in the cooperative calibration phase will be applied to the cooperative mobile positioning algorithm developed in previous works.

TUTGNSS University based hardware/software GNSS receiver for research purposes

Recently a lot of research has been going on in the field of Global Navigation Satellite System receivers. Only few projects have been providing open source hardware receivers. In this paper we present a university based GNSS receiver intended for open source release. The highly modular design of the receiver is described in detail. We also provide description of the software parts and advanced user interface of the receiver. In the end of the paper a test scenario is provided proving the functionality of the receiver design. The presented GNSS receiver architecture is expected to be valuable prototype for research purposes.

Ad Hoc Networks for Cooperative Mobile Positioning

Wireless ad-hoc networks have received huge attention during recent years due to the potential applications in different fields such as emergency, disaster relief, battle-fields, automotive, social networks and entertainment. They are rapidly deployable, selforganizing, and require no fixed infrastructure for communications. (Huang et al., 2008) At the same time, localization in wireless networks is becoming a hot topic for society, industry and research. The needs of location information has driven companies to build mobile handsets with embedded GPS receivers (which is nowadays the most popular mass market solution for positioning), causing huge increase in costs, size, battery consumption, and a long time for a full market penetration (Sayed et al., 2005). However, it is also known that the GPS is not always the most suitable solution for localization. In adverse environments, such as outdoor urban canyons and indoor, it is not an easy task to obtain location information, due to the signal blocking, multipath conditions and the infeasibility to have a continuous tracking of at least four satellites (Mayorga et al., 2007). The Fourth generation (4G) communication systems also stimulate the need of providing alternative ubiquitous localization solutions, regardless the environment (i.e., outdoors and indoors), which should overcome, or at least complement, the drawbacks of GPS-based and GPS-free systems (Della Rosa, 2007). Traditional alternative technologies make use of time difference of arrival (TDOA) measurements from the serving cellular system where the Base Stations (BSs) are considered as fixed reference points (Sayed et al., 2005). Different type of measurements, such as received signal strength (RSS), are widely used in local area scenarios, where Wi-Fi Hot Spots deployed in big cities allow user terminals to predict their locations by means of known fixed positions (Sayed et al., 2005). Unfortunately, when localization is performed in indoor environments the accuracy is highly dependent on the wireless channel conditions since several error sources cause huge signal fluctuations detected at terminal level, severely decreasing the final location estimation accuracy (Della Rosa et al., 2010). Recently, in alternative to traditional methods, a new branch of positioning techniques has been developed: the Cooperative Mobile Positioning (Figueiras & Frattasi, 2010), which makes use of hybrid schemes and exploits the benefits in terms of accuracy of short-range measurements provided by the ad-hoc networks (Della Rosa, 2007).

Relative positioning of mass market devices in ad-hoc networks

In this paper we present a practical approach to relative positioning of heterogeneous mass market devices. We propose a user-centric solution exploiting measurements from on-the-fly fixed reference points detected during scanning procedures. The technique implemented on mobile devices is able to locate neighboring nodes, demonstrating to be a feasible and practical solution for sensing spatial social contexts in ad-hoc environments.

GRAMMAR: Challenges and solutions for multi-constellation Mass Market user Receivers

In this paper we describe the prototype concept of multi-constellation GNSS receivers investigated in the Galileo Ready Advanced Mass Marker Receiver (GRAMMAR) EU FP7 project [1]. The purpose of our work is to provide technology solutions with their implementations for multi-system GNSS mass market receivers by motivating the need for both hardware and software research and present the functional blocks for a multi-constellation GNSS receiver.