The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Huang-chen Lee - One of the best experts on this subject based on the ideXlab platform.
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monitoring of large area iot sensors using a LoRa wireless mesh network system design and evaluation
IEEE Transactions on Instrumentation and Measurement, 2018Co-Authors: Huang-chen LeeAbstract:Although many techniques exist to transfer data from the widely distributed sensors that make up the Internet of Things (IoT) (e.g., using 3G/4G networks or cables), these methods are associated with prohibitively high costs, making them impractical for real-life applications. Recently, several emerging wireless technologies have been proposed to provide long-range communication for IoT sensors. Among these, LoRa has been examined for long-range performance. Although LoRa shows good performance for long-range transmission in the countryside, its radio signals can be attenuated over distance, and buildings, trees, and other radio signal sources may interfere with the signals. Our observations show that in urban areas, LoRa requires dense deployment of LoRa gateways (GWs) to ensure that indoor LoRa devices can successfully transfer data back to remote GWs. Wireless mesh networking is a solution for increasing communication range and packet delivery ratio (PDR) without the need to install additional GWs. This paper presents a LoRa mesh networking system for large-area monitoring of IoT applications. We deployed 19 LoRa mesh networking devices over an $800\,\,\text {m} \times 600$ m area on our university campus and installed a GW that collected data at 1-min intervals. The proposed LoRa mesh networking system achieved an average 88.49% PDR, whereas the star-network topology used by LoRa achieved only 58.7% under the same settings. To the best of our knowledge, this is the first academic study discussing LoRa mesh networking in detail and evaluating its performance via real experiments.
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Demo Abstract: A LoRa Wireless Mesh Networking Module for Campus-Scale Monitoring
2017 16th ACM IEEE International Conference on Information Processing in Sensor Networks (IPSN), 2017Co-Authors: Q W Liang, J. H. Lin, G J Zeng, Huang-chen LeeAbstract:LoRa, an emerging wireless technology, is examined for long range communication performance in a large area. Although LoRa shows good performance for long-distance transmission in the countryside, its radio signals can be attenuated and interfered with by buildings, trees and other signal sources. In urban areas, our observation shows that LoRa requires a dense deployment of LoRa gateways to ensure that indoor LoRa devices can transfer data back to remote servers. Mesh networking is a solution for increasing the communication range and packet delivery ratio without the need to install additional LoRa gateways. This study presents our design of a LoRa mesh-networking module for IoT applications (e.g.,collecting data from multiple, widely distributed sensors on a university campus). We deployed 19 LoRa mesh-networking devices distributed in an 800m by 600m area on campus to serve as a gateway and to collect data at one-minute intervals. The results show our LoRa mesh networking module achieved a 88.49% packet delivery ratio (PDR), while the LoRaWAN in star-network topology was only 58.7% under the same conditions.
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A LoRa wireless mesh networking module for campus-scale monitoring: demo abstract
Proceedings of the 16th …, 2017Co-Authors: Kai Hsiang Ke, J. H. Lin, Q W Liang, G J Zeng, Huang-chen LeeAbstract:LoRa, an emerging wireless technology, is examined for long range communication performance in a large area. Although LoRa shows good performance for long-distance transmission in the countryside, its radio signals can be attenuated and interfered with by buildings, trees and other signal sources. In urban areas, our observation shows that LoRa requires a dense deployment of LoRa gateways to ensure that indoor LoRa devices can transfer data back to remote servers. Mesh networking is a solution for increasing the communication range and packet delivery ratio without the need to install additional LoRa gateways. This study presents our design of a LoRa mesh-networking module for IoT applications (e.g.,collecting data from multiple, widely distributed sensors on a university campus). We deployed 19 LoRa mesh-networking devices distributed in an 800m by 600m area on campus to serve as a gateway and to collect data at one-minute intervals. The results show our LoRa mesh networking module achieved a 88.49% packet delivery ratio (PDR), while the LoRaWAN in star-network topology was only 58.7% under the same conditions.
Yuanqing Zheng - One of the best experts on this subject based on the ideXlab platform.
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FTrack: Parallel Decoding for LoRa Transmissions
IEEE ACM Transactions on Networking, 2020Co-Authors: Xianjin Xia, Yuanqing ZhengAbstract:LoRa has emerged as a promising Low-Power Wide Area Network (LP-WAN) technology to connect a huge number of Internet-of-Things (IoT) devices. The dense deployment and an increasing number of IoT devices lead to intense collisions due to uncoordinated transmissions. However, the current MAC/PHY design of LoRaWAN fails to recover collisions, resulting in degraded performance as the system scales. This article presents FTrack, a novel communication paradigm that enables demodulation of collided LoRa transmissions. FTrack resolves LoRa collisions at the physical layer and thereby supports parallel decoding for LoRa transmissions. We propose a novel technique to separate collided transmissions by jointly considering both the time domain and the frequency domain features. The proposed technique is motivated from two key observations: (1) the symbol edges of the same frame exhibit periodic patterns, while the symbol edges of different frames are usually misaligned in time; (2) the frequency of LoRa signal increases continuously in between the edges of symbol, yet exhibits sudden changes at the symbol edges. We detect the continuity of signal frequency to remove interference and further exploit the time-domain information of symbol edges to recover symbols of all collided frames. We substantially optimize computation-intensive tasks and meet the real-time requirements of parallel LoRa decoding. We implement FTrack on a low-cost software defined radio. Our testbed evaluations show that FTrack demodulates collided LoRa frames with low symbol error rates in diverse SNR conditions. It increases the throughput of LoRaWAN in real usage scenarios by up to 3 times.
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ftrack parallel decoding for LoRa transmissions
International Conference on Embedded Networked Sensor Systems, 2019Co-Authors: Xianjin Xia, Yuanqing ZhengAbstract:LoRa has emerged as a promising Low-Power Wide Area Network (LP-WAN) technology to connect a huge number of Internet-of-Things (IoT) devices. The dense deployment and an increasing number of IoT devices lead to intense collisions due to uncoordinated transmissions. However, the current MAC/PHY design of LoRaWAN fails to recover collisions, resulting in degraded performance as the system scales. This paper presents FTrack, a novel communication paradigm that enables demodulation of collided LoRa transmissions. FTrack resolves LoRa collisions at the physical layer and thereby supports parallel decoding for LoRa transmissions. We propose a novel technique to separate collided transmissions by jointly considering both the time domain and the frequency domain features. The proposed technique is motivated from two key observations: (1) the symbol edges of the same frame exhibit periodic patterns, while the symbol edges of different frames are usually misaligned in time; (2) the frequency of LoRa signal increases continuously in between the edges of symbol, yet exhibits sudden changes at the symbol edges. We detect the continuity of signal frequency to remove interference and further exploit the time-domain information of symbol edges to recover symbols of all collided frames. We implement FTrack on a low-cost software defined radio. Our testbed evaluations show that FTrack demodulates collided LoRa frames with low symbol error rates in diverse SNR conditions. It increases the throughput of LoRaWAN in real usage scenarios by up to 3 times.
Mondrag\uf3n Izquierdo Alcides - One of the best experts on this subject based on the ideXlab platform.
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PRIMER REPORTE DE Cheilanthes microphylla (Sw.) Sw. (PTERIDACEAE) PARA EL ESTADO LARA, VENEZUELA. (Nota T\ue9cnica)
2014Co-Authors: Mondrag\uf3n Izquierdo AlcidesAbstract:Los helechos poseen un indiscutible valor ornamental, otros se utilizan en medicina popular y algunas especies son consideradas indicadoras de alteraci\uf3n ambiental, mientras que otras pueden llegar a transformarse en malezas dif\uedciles de eliminar. Com\ufanmente, se considera que los helechos se desarrollan en lugares h\ufamedos y umbrosos; sin embargo, existen especies adaptadas a vivir en lugares soleados y con limitaciones h\ueddricas como es el caso del g\ue9nero Cheilanthes, cuyas especies se desarrollan en ambientes predominantemente semi\ue1ridos y de suelos pedregosos. El objetivo del presente trabajo es contribuir con el conocimiento de la fLoRa pteridol\uf3gica del estado Lara, Venezuela. Se realizaron varias expLoRaciones bot\ue1nicas en diferentes localidades de la sierra de Baragua del municipio Urdaneta de esta entidad y se encontr\uf3 a Cheilanthes microphylla (Sw.) Sw. (Pteridaceae) como la \ufanica especie de este grupo que crec\ueda en pendientes pedregosas en un bosque xerof\uedtico de la localidad de El Ralo. Esta especie se caracteriza por presentar l\ue1mina 2-pinnado-pinnatifida con indusios discontinuos entre los l\uf3bulos. Este trabajo constituye el primer reporte de la especie para el estado Lara, a la vez que representa el primer registro de una especie de Pteridophyta para el municipio Urdaneta, y constituye un significativo aporte a la fLoRa de esta regi\uf3n, la cual hasta el presente ha sido poco expLoRada desde el punto bot\ue1nico. Abstract First report of Cheilanthes microphylla (Sw.) Sw. (Pteridaceae) from Lara State, Venezuela Ferns exhibit an undisputable ornamental value, other species are used in popular medicine, and some species are considered as environment disturbance indicators; even others can constitute in weeds hard to eradicate. Ferns are commonly considered as associated to humid and shadowy environments; however, some species adapt to sun exposed and water restricted areas, such as Cheilanthes, whose species grow predominantly in semi-arid areas with stony soils. This work aimed to improve knowledge about pteridologic fLoRa from Lara State, Venezuela. Several botanical expLoRations were carried out in different locations at Baragua sierra, Urdaneta municipality of the State. Cheilanthes microphylla (Sw.) Sw. (Pteridaceae) was found as the unique species from this group growing in stony slopes in a xerophytic forest from El Ralo town. This species shows 2-pinnate-pinnatifida frond with discontinued indusia between lobes. This constitutes the first report of this species from Lara State, and also it is the first record of a Pteridophyta species from Urdaneta municipality, representing a significant contribution to the fLoRa from this region, which has been botanically poorly explored so far. Additional key words: Fern, Urdaneta municipality, Baragua sierr
Ahmed Elzanaty - One of the best experts on this subject based on the ideXlab platform.
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on the LoRa modulation for iot waveform properties and spectral analysis
arXiv: Networking and Internet Architecture, 2019Co-Authors: Marco Chiani, Ahmed ElzanatyAbstract:An important modulation technique for Internet of Things (IoT) is the one proposed by the LoRa allianceTM. In this paper we analyze the M-ary LoRa modulation in the time and frequency domains. First, we provide the signal description in the time domain, and show that LoRa is a memoryless continuous phase modulation. The cross-correlation between the transmitted waveforms is determined, proving that LoRa can be considered approximately an orthogonal modulation only for large M. Then, we investigate the spectral characteristics of the signal modulated by random data, obtaining a closed-form expression of the spectrum in terms of Fresnel functions. Quite surprisingly, we found that LoRa has both continuous and discrete spectra, with the discrete spectrum containing exactly a fraction 1/M of the total signal power.
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On the LoRa Modulation for IoT: Waveform Properties and Spectral Analysis
IEEE Internet of Things Journal, 2019Co-Authors: Marco Chiani, Ahmed ElzanatyAbstract:An important modulation technique for Internet of Things (IoT) is the one proposed by the low power long range (LoRa) alliance. In this paper, we analyze the $M$ -ary LoRa modulation in the time and frequency domains. First, we provide the signal description in the time domain, and show that LoRa is a memoryless continuous phase modulation. The cross-correlation between the transmitted waveforms is determined, proving that LoRa can be considered approximately an orthogonal modulation only for large $M$ . Then, we investigate the spectral characteristics of the signal modulated by random data, obtaining a closed-form expression of the spectrum in terms of Fresnel functions. Quite surprisingly, we found that LoRa has both continuous and discrete spectra, with the discrete spectrum containing exactly a fraction $1/M$ of the total signal power.
Carlos Vasquez - One of the best experts on this subject based on the ideXlab platform.
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primer reporte de cheilanthes microphylla sw sw pteridaceae para el estado lara venezuela
Bioagro (Venezuela) Num.3 Vol.26, 2014Co-Authors: Alcides Mondragon, Hipolito Alvarado, Carlos VasquezAbstract:Los helechos poseen un indiscutible valor ornamental, otros se utilizan en medicina popular y algunas especies son consideradas indicadoras de alteracion ambiental, mientras que otras pueden llegar a transformarse en malezas dificiles de eliminar. Comunmente, se considera que los helechos se desarrollan en lugares humedos y umbrosos; sin embargo, existen especies adaptadas a vivir en lugares soleados y con limitaciones hidricas como es el caso del genero Cheilanthes, cuyas especies se desarrollan en ambientes predominantemente semiaridos y de suelos pedregosos. El objetivo del presente trabajo es contribuir con el conocimiento de la fLoRa pteridologica del estado Lara, Venezuela. Se realizaron varias expLoRaciones botanicas en diferentes localidades de la sierra de Baragua del municipio Urdaneta de esta entidad y se encontro a Cheilanthes microphylla (Sw.) Sw. (Pteridaceae) como la unica especie de este grupo que crecia en pendientes pedregosas en un bosque xerofitico de la localidad de El Ralo. Esta especie se caracteriza por presentar lamina 2-pinnado-pinnatifida con indusios discontinuos entre los lobulos. Este trabajo constituye el primer reporte de la especie para el estado Lara, a la vez que representa el primer registro de una especie de Pteridophyta para el municipio Urdaneta, y constituye un significativo aporte a la fLoRa de esta region, la cual hasta el presente ha sido poco expLoRada desde el punto botanico.
