Estrella M. Garcia-Lozano

A Bandwidth-Efficient Service for Local Information Dissemination in Sparse to Dense Roadways

Thanks to the research on Vehicular Ad Hoc Networks (VANETs), we will be able to deploy applications on roadways that will contribute to energy efficiency through a better planning of long trips. With this goal in mind, we have designed a gas/charging station advertising system, which takes advantage of the broadcast nature of the network. We have found that reducing the number of total sent packets is important, as it allows for a better use of the available bandwidth. We have designed improvements for a distance-based flooding scheme, so that it can support the advertising application with good results in sparse to dense roadway scenarios.

Bandwidth efficient broadcasting in VANETs

Wireless communications amongst vehicles bring the opportunity for a wide range of applications, from safety aid to passenger entertainment. The necessity to broadcast information to several-hop neighbors is common to most of the potential application protocols. Broadcast protocols for VANETs based on diverse techniques have already been proposed. In this article, we compare basic broadcast schemes that are not dependent on neighbor knowledge using ns-2 - simple flooding, probabilistic, counter-based, distance-based and traffic-based broadcast. The objective is to obtain general directions for the design of a bandwidth efficient broadcast. Based on this comparison, we have selected distance-based flooding and proposed a scheme that is easy to adjust to the applications necessities.

Adapting a Bandwidth-Efficient Information Dissemination Scheme for Urban VANETs

The recent release of standards for vehicular communications will hasten the development of smart cities in the following years. However, the standards do not define efficient schemes for infotainment dissemination over urban networks. These networks present special features and difficulties that may require special measures. In a previous work, we proposed three different schemes. The preliminary results of the three were satisfying but we still had to explore the values for some parameters that affect significantly their behavior. In this article, we tackle this task. Our findings clear up the strengths and weaknesses of each scheme and open the door to new advances.

A Bandwidth-Efficient Dissemination Scheme of Non-Safety Information in Urban VANETs

The recent release of standards for vehicular communications will hasten the development of smart cities in the following years. Many applications for vehicular networks, such as blocked road warnings or advertising, will require multi-hop dissemination of information to all vehicles in a region of interest. However, these networks present special features and difficulties that may require special measures. The dissemination of information may cause broadcast storms. Urban scenarios are especially sensitive to broadcast storms because of the high density of vehicles in downtown areas. They also present numerous crossroads and signal blocking due to buildings, which make dissemination more difficult than in open, almost straight interurban roadways. In this article, we discuss several options to avoid the broadcast storm problem while trying to achieve the maximum coverage of the region of interest. Specifically, we evaluate through simulations different ways to detect and take advantage of intersections and a strategy based on store-carry-forward to overcome short disconnections between groups of vehicles. Our conclusions are varied, and we propose two different solutions, depending on the requirements of the application.

Bandwidth-efficient techniques for information dissemination in urban vehicular networks

Many applications for vehicular networks, such as blocked road warnings or advertising, will require multi-hop dissemination of information to all vehicles in a region of interest. However, this type of communication can cause broadcast storms. Urban scenarios are especially sensitive to broadcast storms because of the high density of vehicles in downtown areas. They also present numerous crossroads and signal blocking due to buildings, that make dissemination more difficult than in open, almost straight interurban roadways. In this article, we study different ways to tackle a multi-hop broadcast of information in an urban area.

An efficient, eco-friendly approach for push-advertising of services in VANETs

Thanks to the research on VANETs, we will be able to deploy applications on highways that will contribute to the energy efficiency through a better planning of long trips. With this goal in mind, we have designed a gas/charging station advertising system, that takes advantage of the broadcast nature of the network. We have found that reducing the number of total sent packets is important, as it allows a better use of the available bandwidth. We have optimized a distance-based flooding scheme so that it can support the advertising application with good results in a highway scenario.

Selection and publication of network interface cards in multihomed pervasive computing devices

Many modern devices come with several, heterogeneous, network interface cards (NICs). However, simple operations like transferring data flows to the cheapest NIC or to one with enough Quality of Service (QoS) are awkward tasks on most Operating Systems. In this paper, we discuss the criteria to select the proper NIC for a given data flow. We also present a new Operating System service, called netqos, to publish data and figures of merit for these criteria. The main objective of netqos is providing relevant information to applications and middleware about NIC selection criteria, isolating them from the idiosyncrasies of the many QoS gathering tools and allowing to choose the proper NIC to fit their needs. We have built this new service as a synthetic file system for the Linux kernel. We describe our experiences in using it in a real-world scenario and the practical and inherent limitations of this approach.

A new traffic information service for smart consumer devices

Consumer devices are a key tool for assisting people with their everyday tasks, such as driving. We have developed a traffic information service for consumer devices. It is able to minimize the consumed bandwidth, and works in either sparse or very dense roadways without any infrastructure.

Characterizing Mobile Telephony Signals in Indoor Environments for Their Use in Fingerprinting-Based User Location

Fingerprinting techniques have been applied to locate users in indoor scenarios using WiFi signals. Although mobile telephony network is used for outdoor location, it is widely deployed and their signal more stable, thus being also a candidate to be used for fingerprinting. This paper describes the characterization of GSM/UMTS signals in indoor scenarios to check if their features allow to use them for constructing the radio maps needed for fingerprinting purposes. We have developed an Android application to collect the received signal information, such that makes the measurement process cheaper and easier. Measurements show that changes in location and device orientation can be identified by observing the received signal strength of the connected and neighboring base stations. Besides, detecting this variability is easier by using the GSM network than with UMTS technology. Therefore mobile telephony network seems suitable to perform fingerprinting-based indoor location.