313 research outputs found
Fast prototyping of an SDR WLAN 802.11b receiver for an indoor positioning system
Indoor positioning systems (IPS) are emerging technologies due to an
increasing popularity and demand in location based service (LBS). Because
traditional positioning systems such as GPS are limited to outdoor
applications, many IPS have been proposed in literature. WLAN-based IPS are the
most promising due to its proven accuracy and infrastructure deployment.
Several WLAN-based IPS have been proposed in the past, from which the best
results have been shown by so-called fingerprint-based systems. This paper
proposes an indoor positioning system which extends traditional WLAN
fingerprinting by using received signal strength (RSS) measurements along with
channel estimates as an effort to improve classification accuracy for scenarios
with a low number of Access Points (APs). The channel estimates aim to
characterize complex indoor environments making it a unique signature for
fingerprinting-based IPS and therefore improving pattern recognition in
radio-maps. Since commercial WLAN cards offer limited measurement information,
software-defined radio (SDR) as an emerging trend for fast prototyping and
research integration is chosen as the best cost-effective option to extract
channel estimates. Therefore, this paper first proposes an 802.11b WLAN SDR
beacon receiver capable of measuring RSS and channel estimates. The SDR is
designed using LabVIEW (LV) environment and leverages several inherent platform
acceleration features that achieve real-time capturing. The receiver achieves a
fast-rate measurement capture of 9 packets per second per AP. The
classification of the propose IPS uses a support vector machine (SVM) for
offline training and online navigation. Several tests are conducted in a
cluttered indoor environment with a single AP in 802.11b legacy mode. Finally,
navigation accuracy results are discussed
A Reduced Complexity Cross-correlation Interference Mitigation Technique on a Real-time Software-defined Radio GPS L1 Receiver
The U.S. global position system (GPS) is one of the existing global
navigation satellite systems (GNSS) that provides position and time information
for users in civil, commercial and military backgrounds. Because of its
reliance on many applications nowadays, it's crucial for GNSS receivers to have
robustness to intentional or unintentional interference. Because most
commercial GPS receivers are not flexible, software-defined radio emerged as a
promising solution for fast prototyping and research on interference mitigation
algorithms. This paper provides a proposed minimum mean-squared error (MMSE)
interference mitigation technique which is enhanced for computational
feasibility and implemented on a real-time capable GPS L1 SDR receiver. The GPS
SDR receiver SW has been optimized for real-time operation on National
Instruments' LabVIEW (LV) platform in conjunction with C/C++ dynamic link
libraries (DLL) for improved efficiency. Performance results of said algorithm
with real signals and injected interference are discussed. The proposed SDR
receiver gains in terms of BER curves for several interferers are demonstrated
GNSS-SDR pseudorange quality and single point positioning performance assessment
In recent years, we have witnessed a growing demand for GNSS receiver customization in terms of modification of signal acquisition, tracking, and processing strategies. Such demands may be addressed by software-defined receivers (SDRs) which refers to an ensemble of hardware and software technologies and allows re-configurable radio communication architectures. The crux of the SDRs is the replacement of the hardware components through software modules. In this paper, we assess the quality of GNSS observables acquired by SDR against the selected u-blox low-cost receiver. In the following, we investigate the performance level of single point positioning that may be reached with an ultra-low-cost SDR and compare it to that of the low-cost GNSS receiver. The signal quality assessment revealed a comparable performance in terms of carrier-to-noise density ratio and a significant out-performance of the u-blox over SDR in terms of code pseudorange noise. The experimentation in the positioning domain proved that software-defined receivers may offer a position solution with three-dimensional standard deviation error at the level of 5.2 m in a single point positioning mode that is noticeably poorer accuracy as compared to the low-cost receiver. Such results demonstrate that there is still room for SDR positioning accuracy improvement
An Integrated Framework for Sensing Radio Frequency Spectrum Attacks on Medical Delivery Drones
Drone susceptibility to jamming or spoofing attacks of GPS, RF, Wi-Fi, and
operator signals presents a danger to future medical delivery systems. A
detection framework capable of sensing attacks on drones could provide the
capability for active responses. The identification of interference attacks has
applicability in medical delivery, disaster zone relief, and FAA enforcement
against illegal jamming activities. A gap exists in the literature for solo or
swarm-based drones to identify radio frequency spectrum attacks. Any
non-delivery specific function, such as attack sensing, added to a drone
involves a weight increase and additional complexity; therefore, the value must
exceed the disadvantages. Medical delivery, high-value cargo, and disaster zone
applications could present a value proposition which overcomes the additional
costs. The paper examines types of attacks against drones and describes a
framework for designing an attack detection system with active response
capabilities for improving the reliability of delivery and other medical
applications.Comment: 7 pages, 1 figures, 5 table
Antenna Selection And MIMO Capacity Estimation For Vehicular Communication Systems
Vehicular communication is one of the promising prospects of wireless communication capable of addressing the issues related to road safety, providing the framework for smart or intelligent cars. To provide a reliable wireless link for vehicular communication extensive channel modeling and measurements are required. In this thesis a novel cost-effective implementation of vehicular channel capacity measuring system using off-the-shelf devices is proposed. Then using the proposed system, various channel measurements are performed. The measurement results are utilized to examine multi-antenna systems for vehicular communication.
The challenge in developing an efficient network between cars is to understand the nature of random channels that changes with the location of antenna, surroundings and obstacles between the transmitting and receiving vehicles. In addition to measurements, in this thesis, the channel behavior has been studied through simulation. Wireless InSite from Remcom was used as a simulation tool to study different vehicular channels in environments with different structures to see the impact of obstacles and surroundings in the performance of the vehicular network. In particular, the behavior of different antenna locations on channel capacity of 2Ã2 Multiple Input Multiple Output (MIMO) systems is investigated. Channel capacities that are obtained from simulation and measurements provide the information about the changing nature of the channel and outline the essential considerations while choosing the antenna positions on the transmitting or receiving vehicles
Vehicular Networking Road Weather Information System Tailored for Arctic Winter Conditions
In order to conduct successful long-term service and system architecture development, permanent infrastructures and development environment are essential. For this purpose, FMI is operating a vehicle winter testing track with advanced communication capabilities within ITS-G5 and 5G test network, along with accurate road weather data and services supported by road weather stations, IoT road weather sensor network and on-board weather measurements. The track is in Sodankylä, Northern Finland, where the long arctic winter period of more than half year allows road weather services development in (and for) severe weather conditions. This environment provides appropriate conditions for the development of advanced ITS safety services equally for traditional, autonomous and alternate energy vehicles, tailored road weather services for each special use case and accurate estimation of performance. Not forgetting the energy efficiency of traffic and communication infrastructures themselves, which are critical elements in the development of the future ITS. This paper introduces the test track infrastructures, related research ambitions and future plans
Implementação de um transceiver para comunicações móveis oportunistas na banda de TV
Dissertação de Mestrado em Comunicações Móveis apresentada à Escola Superior de Tecnologia do Instituto Politécnico de Castelo Branco.This document describes the work developed to implement a prototype able to operate in TVWS.Gives an overview about the digital switchover roadmap in Europe and surveys the trends in the TVWS market for different European countries. Describe the prototype specifications, also an overview about the TVWS prototype state of art. Describes the sensing techniques for PMSE detecting used in the prototype and the thresholds calculations.The metrics to evaluate the algorithms selected are presents. Also, describes the SDR systems, the chosen hardware, USRP and the features and limits, daughterboard selected. A resume about the software platform is present and the features that make this platform, Labview, the choice for integrating in the prototype Describes the development and implementation of the prototype and also include the test scenario conditions and results
- …