Papers by Marc Ciurana Adell
TDX (Tesis Doctorals en Xarxa), Jul 15, 2010
La consulta d'aquesta tesi queda condicionada a l'acceptació de les següents condicions d'ús: La ... more La consulta d'aquesta tesi queda condicionada a l'acceptació de les següents condicions d'ús: La difusió d'aquesta tesi per mitjà del servei TDX (www.tesisenxarxa.net) ha estat autoritzada pels titulars dels drets de propietat intel•lectual únicament per a usos privats emmarcats en activitats d'investigació i docència. No s'autoritza la seva reproducció amb finalitats de lucre ni la seva difusió i posada a disposició des d'un lloc aliè al servei TDX. No s'autoritza la presentació del seu contingut en una finestra o marc aliè a TDX (framing). Aquesta reserva de drets afecta tant al resum de presentació de la tesi com als seus continguts. En la utilització o cita de parts de la tesi és obligat indicar el nom de la persona autora. ADVERTENCIA. La consulta de esta tesis queda condicionada a la aceptación de las siguientes condiciones de uso: La difusión de esta tesis por medio del servicio TDR (www.tesisenred.net) ha sido autorizada por los titulares de los derechos de propiedad intelectual únicamente para usos privados enmarcados en actividades de investigación y docencia. No se autoriza su reproducción con finalidades de lucro ni su difusión y puesta a disposición desde un sitio ajeno al servicio TDR. No se autoriza la presentación de su contenido en una ventana o marco ajeno a TDR (framing). Esta reserva de derechos afecta tanto al resumen de presentación de la tesis como a sus contenidos. En la utilización o cita de partes de la tesis es obligado indicar el nombre de la persona autora. WARNING. On having consulted this thesis you're accepting the following use conditions: Spreading this thesis by the TDX (www.tesisenxarxa.net) service has been authorized by the titular of the intellectual property rights only for private uses placed in investigation and teaching activities. Reproduction with lucrative aims is not authorized neither its spreading and availability from a site foreign to the TDX service. Introducing its content in a window or frame foreign to the TDX service is not authorized (framing). This rights affect to the presentation summary of the thesis as well as to its contents. In the using or citation of parts of the thesis it's obliged to indicate the name of the author
AbstractThis paper presents a new approach to providing accurate pedestrian indoor positioning u... more AbstractThis paper presents a new approach to providing accurate pedestrian indoor positioning using a Time of Arrival (TOA) based technique, when only two access points in an IEEE 802.11 network are in range of a mobile terminal to be located. This allows to enhance the ...
Computer Communications, Aug 1, 2009
This article presents a novel technique to track WLAN terminals based on Time of Arrival (TOA). T... more This article presents a novel technique to track WLAN terminals based on Time of Arrival (TOA). The objective of this research is enhancing the accuracy and availability of Newton-based WLAN positioning. Two tracking algorithms have been designed for this purpose. Results obtained from simulations run using true ranging observables demonstrate the suitability of the proposed algorithms. This technique allows the tracking of mobile terminals in real-time indoors with around 1.5 m of error with three access points at sight. Additionally, tracking with only two access points is possible with an accuracy drop of around 1 m. Other advantages of the proposed solution include its flexibility of deployment and costeffectiveness.
Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measureme... more Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measurements at data link level. This procedure allows using the existing IEEE 802.11 WLAN infrastructure with minor changes in order to provide an accurate estimation of the position of the mobile terminal. In this paper, an approach to overcome the undesired impact of the indoor radio-channel multipath on the accuracy of the TOA estimation between the terminal and an Access Point is presented. Ranging errors caused by multipath are quantified for different channel profiles: Dominant Direct Path (DDP), Non Dominant Direct Path (NDDP) and Undetectable Direct Path (UDP). However, the main challenge corresponds to be able to identify this profile (i.e. the multipath condition) from the obtained RTT measurements at IEEE 802.11 link level. This allows applying a TOA estimation algorithm sensitive to the detected profile in order to minimize the TOA estimation error.
Solucio de posicionament precis ubic i en temps real per a vehicles, basat en l'us de xarxes ... more Solucio de posicionament precis ubic i en temps real per a vehicles, basat en l'us de xarxes Wi-Fi i de posicionament per satel·lit. Es desplega en la propia unitat embarcada del vehicle. La principal caracteristica diferencial respecte les solucions classiques es la seva ubiquitat (indoor-outdoor).
Location techniques that satisfy the requirements of advanced Location-Based Services (LBS) in en... more Location techniques that satisfy the requirements of advanced Location-Based Services (LBS) in environments where GPS fails are needed, therefore accurate indoor positioning is becoming increasingly important. This PhD Thesis is devoted to the research on location of mobile devices employing WLAN (IEEE 802.11). The use of this kind of wireless networks infrastructures for positioning enables a powerful synergy between communications and location and allows solutions with good performances at moderated costs. However the adopted WLAN location methods suffer from important limitations that prevents from applying them to some fields that need more flexible and robust solutions. The main objective of this PhD is exploring precise WLAN location methods that allow overcoming these limitations. The researched methods here are based on measuring the Time Of Arrival (TOA), which is the time that takes the signal propagating from the transmitter to the receiver. TOA-based location works in tw...
Solucio de posicionament precis ubic i en temps real per a vehicles, basat en l'us de xarxes ... more Solucio de posicionament precis ubic i en temps real per a vehicles, basat en l'us de xarxes Wi-Fi i de posicionament per satel·lit. Es desplega en la propia unitat embarcada del vehicle. La principal caracteristica diferencial respecte les solucions classiques es la seva ubiquitat (indoor-outdoor).
2008 5th Workshop on Positioning, Navigation and Communication, 2008
Proceedings of the 1st international workshop on Wireless network testbeds, experimental evaluation & characterization, 2006
Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measureme... more Indoor ranging and location in WLAN is possible through obtaining Round-Trip-Time (RTT) measurements at data link level. This procedure allows using the existing IEEE 802.11 WLAN infrastructure with minor changes in order to provide an accurate estimation of the position of the mobile terminal. In this paper, an approach to overcome the undesired impact of the indoor radio-channel multipath on the accuracy of the TOA estimation between the terminal and an Access Point is presented. Ranging errors caused by multipath are quantified for different channel profiles: Dominant Direct Path (DDP), Non Dominant Direct Path (NDDP) and Undetectable Direct Path (UDP). However, the main challenge corresponds to be able to identify this profile (i.e. the multipath condition) from the obtained RTT measurements at IEEE 802.11 link level. This allows applying a TOA estimation algorithm sensitive to the detected profile in order to minimize the TOA estimation error.
Radio Communications, 2010
An ad hoc 1 network is defined as a decentralised wireless network that is set up on-the-fly for ... more An ad hoc 1 network is defined as a decentralised wireless network that is set up on-the-fly for a specific purpose. These networks were proposed years ago for military use, with the purpose of communicating devices in a highly constrained scenario. Under such a network, devices join and leave the network dynamically; thus, it cannot be expected to have any kind of network infrastructure. This wish for decentralised on-the-fly networks has subsequently expanded to cover several fields besides the military. Today, there are several mobile services requiring the self-organising capabilities that ad hoc networks offer. Examples include packet tracking, online-gaming, and measuring systems, among others. Ad hoc networks have obvious benefits for mobile services, but they also introduce new issues that regular network protocols cannot cope with, including optimum routing, network fragmentation, reduced calculation power, energy-constrained terminals, etc. In ad hoc networks, positioning takes a significant role, mainly due to the on-the-fly condition. In fact, several services require nodes to know the position of the customers in order to perform their duty properly. Wireless sensor networks concentrate most of the services that need positioning to perform their duty. Such networks constitute a subset of ad hoc networks involving dense topologies operating in an ad hoc fashion, and they are composed of small, energy and computation constrained terminals. In ad hoc networks, and especially in wireless sensor networks, nodes are spread over a certain area without a precise knowledge about the topology. In fact, this topology is variable. Accordingly, there are several unknowns (e.g., node density and coverage, network's energy map, the presence of shadowed zones, nodes' placement in the network coverage area) that are likely to constrain the performance of ad hoc services. Knowledge of the terminals' locations can substantially improve the service performance. Positioning is not only important for the service provisioning; it is also crucial in the ad hoc protocol stack development. Due to the changes in the topology and the lack of communication infrastructure, ad hoc protocols have to address several issues not present in regular cellular networks. Routing is one of the best examples of the dependence of ad hoc networks on positioning. Studies such as (Stojmenovic, 2002) demonstrate that only position-based routing protocols are scalable, i.e., able to cope with a higher density of 1 "Ad hoc" is actually a Latin phrase that means "to this (thing, purpose, end, etc.)" 31 www.intechopen.com Radio Communications 620 nodes in the network. The same seems to apply to other management and operation tasks in ad hoc networks. 1.1 The Location problem in ad hoc networks Nodes in an ad hoc network can be grouped into three categories according to the positioning capabilities: beacon nodes, settled nodes, and unknown nodes. Beacon nodes, also known as anchors or landmarks, are those able to compute their position on their own, i.e., without using an ad hoc location algorithm. Accordingly, they implement at least one location technique (e.g., GPS, map matching), which can be used as standalone. Beacon nodes usually constitute the reference frame necessary to set up a location algorithm. Unknown nodes are those nodes that do not know their position yet. When an ad hoc network is set up, all nodes except the beacon nodes are unknown. Settled nodes are unknown nodes that are able to compute their position from the information that they exchange with beacon nodes and/or other settled nodes. The purpose of the ad hoc location system is thus to position as many nodes as possible, turning them from unknown to settled nodes (Bourkerche et al., 2007). Location systems in ad hoc networks function in two steps: local positioning and positioning algorithm. The former is responsible for computing the position of an unknown node from the metrics gathered. The second step consists of the positioning algorithm, which indicates how the position information is managed in order to maximise the number of nodes being settled. 1.2 Measuring the performance of location solutions Performance of location solutions in ad hoc networks can be computed according to several parameters. The main ones are presented below. 1.2.1 Accuracy Ad hoc positioning requires good accuracy since most of the networks in ad hoc mode are deployed in constrained scenarios, often indoors. In such environments, accuracy is especially relevant, since a few meters of error in the position may cause the node to be identified in another room, floor, or even building. Furthermore, nodes are expected to be very close (e.g., in medical applications), and inaccurate positions could hinder operation and maintenance tasks or even prevent location-based applications from performing their duty. Thus, location algorithms for ad hoc networks must produce positions for settled nodes of the highest possible accuracy.
Computer Communications, 2009
This article presents a novel technique to track WLAN terminals based on Time of Arrival (TOA). T... more This article presents a novel technique to track WLAN terminals based on Time of Arrival (TOA). The objective of this research is enhancing the accuracy and availability of Newton-based WLAN positioning. Two tracking algorithms have been designed for this purpose. Results obtained from simulations run using true ranging observables demonstrate the suitability of the proposed algorithms. This technique allows the tracking of mobile terminals in real-time indoors with around 1.5 m of error with three access points at sight. Additionally, tracking with only two access points is possible with an accuracy drop of around 1 m. Other advantages of the proposed solution include its flexibility of deployment and costeffectiveness.
2007 4th Workshop on Positioning, Navigation and Communication, 2007
AbstractThis paper presents a new approach to providing accurate pedestrian indoor positioning u... more AbstractThis paper presents a new approach to providing accurate pedestrian indoor positioning using a Time of Arrival (TOA) based technique, when only two access points in an IEEE 802.11 network are in range of a mobile terminal to be located. This allows to enhance the ...
This paper discusses the implementation of a modified IEEE 802.11 transceiver that is employed to... more This paper discusses the implementation of a modified IEEE 802.11 transceiver that is employed to enhance the positioning capabilities of a traditional vehicle on-board navigation unit (OBU). In this paper, we propose to use the current wireless local access network (WLAN) as enhancing infrastructure for ubiquitous localisation and positioning. We describe the architecture of a localisation receiver built around a FPGA that is capable of measuring the signal round trip time and thus distance between itself and visible WiFi access points. The proposed system has great potentials to enhance the performance of traditional hardware solutions often based on GNSS plus INS traditionally used as fundamental component in an intelligent transportation system. The proposed system offers vehicle-to-vehicle communication and ranging capabilities using the current IEEE 802.11 standard. This paper describes the details of the WLAN ranging estimation method, possible integration approaches with a G...
Nowadays, several systems are available for outdoor location (i.e GPS, cellular networks based…).... more Nowadays, several systems are available for outdoor location (i.e GPS, cellular networks based…). However, there is no proper location system for indoor scenarios. The technique presented in this paper proposes the use of the existing wireless LAN infrastructure with minor changes to provide an accurate estimation of the location of mobile devices in indoor environments. This technique is based on round-trip time (RTT) measurements, which are used to estimate TOA and distances between the device to be located and WLAN access points. To avoid the cumbersome modification of the physical layer, each RTT is estimated between the transmission of an IEEE 802.11 link layer data frame and the reception of the associated acknowledgement (ACK). By applying trilateration algorithms, an accurate estimation of the mobile position is calculated.
Recent Advances in Communications and Networking Technology, 2015
Accuracy and scalability contribute to the quality of location solutions in wireless networks. Wh... more Accuracy and scalability contribute to the quality of location solutions in wireless networks. While accuracy is a parameter addressed in all location technologies, scalability is often relegated. However, scalability becomes an actual issue in positioning solutions based message exchange (e.g. measuring ranges from beacons). The passive TDOA algorithm is a solution designed to localize terminals in a mobile ad hoc network in a passive way. It is achieved by computing time-differences of arrival from messages being exchanged by other network nodes (i.e. the active nodes), but just listening to the radio channel. In advanced stages of the passive TDOA algorithm (i.e. autonomous passive TDOA recently patented), it is able to compute the position of the unknown node (i.e. the passive node) and of the nodes which the listened location messages belong to (i.e. the active nodes). Thus, the requirement of active nodes informing about its own position to passive nodes is overcome. From the network perspective, the impact of this joint-position computation: it boosts the scalability since less information is transmitted and it helps to improve the accuracy of the active nodes, because passive nodes can report several positions regarding a single active node. However, the accuracy of the positions computed by means of the passive TDOA algorithm needs to be good enough to attend the user’s demands. The aim of this work is analyzing the accuracy achieved by the passive TDOA, focusing on the loss of precision due to passivity if compared with conventional two-way time-of-arrival active solutions, which passive TDOA is rely on.
2010 International Conference on Indoor Positioning and Indoor Navigation, 2010
... position ambiguity. Fernández, Daniel; Barceló-Arroyo, Francisco; Martín Escalona, Israel; Ci... more ... position ambiguity. Fernández, Daniel; Barceló-Arroyo, Francisco; Martín Escalona, Israel; Ciurana Adell, Marc; Jofre, Martí; Gutiérrez, Esteban. Impacto del modelo de error en distancia en la simulación de sistemas de localización. ...
2011 IEEE Symposium on Computers and Communications (ISCC), 2011
This paper proposes a positioning method that combines GPS pseudoranges and WLAN ranges when less... more This paper proposes a positioning method that combines GPS pseudoranges and WLAN ranges when less than four GPS satellites are within sight. To enhance the positioning availability, a tight hybridization approach with both technologies is considered. Although the work has been performed considering WLAN and GPS, most of the presented ideas, procedures and results are also valid for generic tight
2006 1st International Symposium on Wireless Pervasive Computing
Nowadays, several systems are available for outdoor localization, such as GPS, assisted GPS and o... more Nowadays, several systems are available for outdoor localization, such as GPS, assisted GPS and other systems working on cellular networks. However, there is no proper location system for indoor scenarios. Research into designing location systems for 802.11 networks is being carried out, so locating mobile devices on global networks (GSM/cellular + GPS + WLAN) finally seems feasible. The technique presented in this paper uses existing wireless LAN infrastructure with minor changes to provide an accurate estimation of the location of mobile devices in indoor environments. This technique is based on round-trip time (RTT) measurements, which are used to estimate distances between the device to be located and WLAN access points. Each RTT measurement estimates the time elapsed between the RTS (Request-to-Send) and the CTS (Clear-to-Send) frame of the 802.11 standard. By applying trilateration algorithms, an accurate estimation of the mobile position is calculated.
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Papers by Marc Ciurana Adell