21 research outputs found
Scalability Analysis of a LoRa Network under Imperfect Orthogonality
Low-power wide-area network (LPWAN) technologies are gaining momentum for
internet-of-things (IoT) applications since they promise wide coverage to a
massive number of battery-operated devices using grant-free medium access.
LoRaWAN, with its physical (PHY) layer design and regulatory efforts, has
emerged as the widely adopted LPWAN solution. By using chirp spread spectrum
modulation with qausi-orthogonal spreading factors (SFs), LoRa PHY offers
coverage to wide-area applications while supporting high-density of devices.
However, thus far its scalability performance has been inadequately modeled and
the effect of interference resulting from the imperfect orthogonality of the
SFs has not been considered. In this paper, we present an analytical model of a
single-cell LoRa system that accounts for the impact of interference among
transmissions over the same SF (co-SF) as well as different SFs (inter-SF). By
modeling the interference field as Poisson point process under duty-cycled
ALOHA, we derive the signal-to-interference ratio (SIR) distributions for
several interference conditions. Results show that, for a duty cycle as low as
0.33%, the network performance under co-SF interference alone is considerably
optimistic as the inclusion of inter-SF interference unveils a further drop in
the success probability and the coverage probability of approximately 10% and
15%, respectively for 1500 devices in a LoRa channel. Finally, we illustrate
how our analysis can characterize the critical device density with respect to
cell size for a given reliability target
Protection of information networks based on LoRa technology
The paper deals with modern technology for transmitting short messages
over long distances named LoRa, where the transmitted signal uses linear
frequency modulation (chirp). The object of the study to define lack of transmitters
that it has a design on LoRa technology for assessment their applicable in
condition urban city where there are a lot of radiation sources. The goal of the
work is the creation of a method of assessing the act the interference conditions
that based on measurement bit error rate and signal-noise ratio and via on which
to get individual host vulnerability levels. The processing of these signals is carried
out by means of a time-frequency transformation. The chirp signal is characterized
by 4 parameters: frequencies, time, modulation rate and amplitude.
By analogy with the wavelet transform, the processing of chirp signals involves
a chirplet decomposition. Since the chirp signals are strongly influenced by mutual
interference due to multipath, the article studies the effectiveness of LoRa
technology in conditions of mutual interference of radiation sources. The developed
method utilized chirplet decomposition and retrieve symbols of a message
in the dictionary. The conducted experiments have confirmed the proposed
software operability and allow recommending it for use in practice for solving
the problems receiving signal. The prospects for further research may include
the creation of parallel methods for calculation of the set of proposed indicators,
the improvement of software, as well as an experimental study of proposed indicators
in real conditions.The paper deals with modern technology for transmitting short messages
over long distances named LoRa, where the transmitted signal uses linear
frequency modulation (chirp). The object of the study to define lack of transmitters
that it has a design on LoRa technology for assessment their applicable in
condition urban city where there are a lot of radiation sources. The goal of the
work is the creation of a method of assessing the act the interference conditions
that based on measurement bit error rate and signal-noise ratio and via on which
to get individual host vulnerability levels. The processing of these signals is carried
out by means of a time-frequency transformation. The chirp signal is characterized
by 4 parameters: frequencies, time, modulation rate and amplitude.
By analogy with the wavelet transform, the processing of chirp signals involves
a chirplet decomposition. Since the chirp signals are strongly influenced by mutual
interference due to multipath, the article studies the effectiveness of LoRa
technology in conditions of mutual interference of radiation sources. The developed
method utilized chirplet decomposition and retrieve symbols of a message
in the dictionary. The conducted experiments have confirmed the proposed
software operability and allow recommending it for use in practice for solving
the problems receiving signal. The prospects for further research may include
the creation of parallel methods for calculation of the set of proposed indicators,
the improvement of software, as well as an experimental study of proposed indicators
in real conditions.National Aviation Universit
Protection of information networks based on LoRa technology
The paper deals with modern technology for transmitting short messages
over long distances named LoRa, where the transmitted signal uses linear
frequency modulation (chirp). The object of the study to define lack of transmitters
that it has a design on LoRa technology for assessment their applicable in
condition urban city where there are a lot of radiation sources. The goal of the
work is the creation of a method of assessing the act the interference conditions
that based on measurement bit error rate and signal-noise ratio and via on which
to get individual host vulnerability levels. The processing of these signals is carried
out by means of a time-frequency transformation. The chirp signal is characterized
by 4 parameters: frequencies, time, modulation rate and amplitude.
By analogy with the wavelet transform, the processing of chirp signals involves
a chirplet decomposition. Since the chirp signals are strongly influenced by mutual
interference due to multipath, the article studies the effectiveness of LoRa
technology in conditions of mutual interference of radiation sources. The developed
method utilized chirplet decomposition and retrieve symbols of a message
in the dictionary. The conducted experiments have confirmed the proposed
software operability and allow recommending it for use in practice for solving
the problems receiving signal. The prospects for further research may include
the creation of parallel methods for calculation of the set of proposed indicators,
the improvement of software, as well as an experimental study of proposed indicators
in real conditions.The paper deals with modern technology for transmitting short messages
over long distances named LoRa, where the transmitted signal uses linear
frequency modulation (chirp). The object of the study to define lack of transmitters
that it has a design on LoRa technology for assessment their applicable in
condition urban city where there are a lot of radiation sources. The goal of the
work is the creation of a method of assessing the act the interference conditions
that based on measurement bit error rate and signal-noise ratio and via on which
to get individual host vulnerability levels. The processing of these signals is carried
out by means of a time-frequency transformation. The chirp signal is characterized
by 4 parameters: frequencies, time, modulation rate and amplitude.
By analogy with the wavelet transform, the processing of chirp signals involves
a chirplet decomposition. Since the chirp signals are strongly influenced by mutual
interference due to multipath, the article studies the effectiveness of LoRa
technology in conditions of mutual interference of radiation sources. The developed
method utilized chirplet decomposition and retrieve symbols of a message
in the dictionary. The conducted experiments have confirmed the proposed
software operability and allow recommending it for use in practice for solving
the problems receiving signal. The prospects for further research may include
the creation of parallel methods for calculation of the set of proposed indicators,
the improvement of software, as well as an experimental study of proposed indicators
in real conditions.National Aviation Universit
Optimisation de la capacitรฉ des rรฉseaux LoRa
International audienc
LoRa ๋คํธ์ํฌ์์ ์๋์ง ํจ์จ์ฑ์ ์ํ ๋ ธ๋ ๊ธฐ๋ฐ ADR ๋ฉ์ปค๋์ฆ
ํ์๋
ผ๋ฌธ (์์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ์ปดํจํฐ๊ณตํ๋ถ, 2020. 8. ๊น์ข
๊ถ.Recently, as Internet of Things (IoT) systems have increased and Wireless Sensor Network (WSN) has been expanding, studies related to them are increasing. Among them, the interest in long range communication technologies has increased. In this regard, Low Power Wide Area (LPWA) network technologies such as Long Range (LoRa), Weightless, and Sigfox have emerged. Also, various studies related to LoRa and LoRaWAN, which are available in Industrial Scientific and Medical (ISM) bands, are being conducted. In LoRa networks, the nodes are connected to the gateway by one hop to form a start topology. LoRa nodes use the transmission parameters such as Spreading Factor (SF), Transmission Power (TP), Bandwidth (BW), Coding Rate (CR), and Carrier Frequency (CF) to transmit frames. In this process, the frame losses and the collisions between frames may occur because of the channel condition and transmission timing. To alleviate this problem, LoRaWAN utilizes the ADR mechanism to select appropriate transmission parameters considering the channel condition on the node side. In addition, there is the ADR mechanism for allocating the transmission parameters on the server side. The ADR mechanisms maintain the connection between the server and the nodes, and set appropriate transmission parameters. However, these existing ADR mechanisms have some limitations. First, the server side ADR mechanism increases the overhead of the server in proportion to the transmitted frames. Second, it is difficult to quickly and efficiently respond to dynamic channel. Third, the transmission parameters selected by these ADR mechanisms may not be the optimal transmission parameters for energy efficiency. These problems cause large energy consumption of the battery-powered nodes and decrease performance when the channel condition changes dynamically. In this paper, we propose a Node-based ADR Mechanism (NbADR), which is the ADR mechanism for Class A nodes in confirmed mode to minimize the server load and maximize energy efficiency. The proposed mechanism responds quickly to the channel condition based on the downlink pattern and selects the transmission parameters for efficient energy consumption by utilizing Efficiency of Energy (EoE) metric. We analyze the efficiency of the transmission parameters selected through EoE, and conduct extensive experiments. In conclusion, NbADR is more effective in terms of energy efficiency than the existing ADR mechanisms. Additionally, NbADR guarantees throughput of LoRa networks even in dynamically changing channel environments and improves fairness between the nodes.์ต๊ทผ IoT ์์คํ
์ด ์ฆ๊ฐํ๊ณ ๋ฌด์ ์ผ์ ๋คํธ์ํฌ๊ฐ ๋์ด์ง๋ฉด์ ์ด์ ๊ด๋ จ๋ ์ฐ๊ตฌ๊ฐ ์ฆ๊ฐํ๊ณ ์๋ค. ๊ทธ ์ค์์๋ ์ฅ๊ฑฐ๋ฆฌ ํต์ ๊ธฐ์ ์ ๋ํ ๊ด์ฌ์ด ์ฆ๊ฐํ๊ณ ์๋ค. ์ด์ ๊ด๋ จํ์ฌ LoRa, Weightless, Sigfox์ ๊ฐ์ LPWA๋คํธ์ํฌ ๊ธฐ์ ๋ค์ด ๋ฑ์ฅํ๊ณ ์๋ค. ๋ํ, ISM ๋ฐด๋์์ ์ฌ์ฉ ๊ฐ๋ฅํ LoRa์ LoRaWAN ๊ด๋ จ ๋ค์ํ ์ฐ๊ตฌ๊ฐ ์งํ๋๊ณ ์๋ค. LoRa ๋คํธ์ํฌ์์ ๋
ธ๋๋ค์ ์คํ ํ ํด๋ก์ง๋ฅผ ๊ตฌ์ฑํ๊ธฐ ์ํ์ฌ ๊ฒ์ดํธ์จ์ด์ 1ํ์ผ๋ก ์ฐ๊ฒฐ๋์ด ์๋ค. LoRa ๋
ธ๋๋ค์ ํ๋ ์์ ์ ์กํ๊ธฐ ์ํ์ฌ SF, TP, BW, CR, CF์ ๊ฐ์ ์ ์ก ํ๋ผ๋ฏธํฐ๋ฅผ ์ฌ์ฉํ๋ค. ์ด ๊ณผ์ ์์ ์ฑ๋ ์ํ์ ์ ์ก ํ์ด๋ฐ์ผ๋ก ์ธํ ํ๋ ์ ์์ค๊ณผ ํ๋ ์ ๊ฐ ์ถฉ๋์ด ๋ฐ์ํ ์ ์๋ค. ์ด๋ฌํ ๋ฌธ์ ๋ฅผ ์ํํ๊ธฐ ์ํ์ฌ LoRaWAN์์๋ ๋
ธ๋ ์ธก์์ ๋คํธ์ํฌ ์ํฉ์ ๊ณ ๋ คํ์ฌ ์ ์ ํ ์ ์ก ํ๋ผ๋ฏธํฐ๋ฅผ ์ ํํ๊ธฐ ์ํ ADR ๋ฉ์ปค๋์ฆ์ ์ฌ์ฉํ๋ค. ๊ฒ๋ค๊ฐ ์๋ฒ ์ธก์์ ์ ์ก ํ๋ผ๋ฏธํฐ๋ฅผ ํ ๋นํ๋ ADR ๋ฉ์ปค๋์ฆ์ด ์กด์ฌํ๋ค. ADR ๋ฉ์ปค๋์ฆ๋ค์ ์๋ฒ์ ๋
ธ๋์ ์ฐ๊ฒฐ์ ์ ์งํ๊ณ ์ ์ ํ ์ ์ก ํ๋ผ๋ฏธํฐ๋ฅผ ์ค์ ํ๋ค. ํ์ง๋ง ๊ธฐ์กด์ ADR ๋ฉ์ปค๋์ฆ๋ค์ ์ผ๋ถ ํ๊ณ์ ์ ๊ฐ์ง๊ณ ์๋ค. ์ฒซ ๋ฒ์งธ, ์๋ฒ ์ธก ADR ๋ฉ์ปค๋์ฆ์ ์ ์กํ๋ ํ๋ ์์ ๋น๋กํ์ฌ ์๋ฒ์ ๋ถํ๋ฅผ ์ฆ๊ฐ์ํจ๋ค. ๋ ๋ฒ์งธ, ๋์ ์ธ ์ฑ๋์์ ๋น ๋ฅด๊ณ ํจ์จ์ ์ผ๋ก ๋์ฒํ๊ธฐ ์ด๋ ต๋ค. ์ธ ๋ฒ์งธ, ์ด๋ฌํ ADR ๋ฉ์ปค๋์ฆ๋ค์์ ์ ํ๋ ์ ์ก ํ๋ผ๋ฏธํฐ๋ค์ด ์๋์ง ํจ์จ์ฑ์ ์ํ ์ต์ ์ ์ ์ก ํ๋ผ๋ฏธํฐ๊ฐ ์๋ ์ ์๋ค. ์ด๋ฌํ ๋ฌธ์ ์ ๋ค์ ๋ฐฐํฐ๋ฆฌ๋ก ๋์ํ๋ ๋
ธ๋๋ค์ ํฐ ์๋์ง ์๋ชจ๋ฅผ ์ผ๊ธฐํ๊ณ LoRa ๋คํธ์ํฌ์ ์ฑ๋์ด ๋์ ์ผ๋ก ๋ณ๊ฒฝ๋๋ ํ๊ฒฝ์์ ์ฑ๋ฅ์ ๊ฐ์์ํจ๋ค. ๋ณธ ๋
ผ๋ฌธ์์ ์ฐ๋ฆฌ๋ ์๋ฒ์ ๋ถํ๋ฅผ ์ต์ํํ๋ฉฐ ์๋์ง ํจ์จ์ฑ์ ์ต๋ํํ๋ ๋
ธ๋ ๊ธฐ๋ฐ์ ADR ๋ฉ์ปค๋์ฆ์ธ NbADR์ ์ ์ํ๋ค. ์ ์ํ๋ ๋ฉ์ปค๋์ฆ์ ๋
ธ๋ ์ธก์์ ์ ์ก ๋ฐ์ ๋ค์ด๋งํฌ ํจํด์ ๊ธฐ๋ฐ์ผ๋ก ์ฑ๋ ์ํฉ์ ๋น ๋ฅด๊ฒ ๋์ํ๊ณ , Efficiency of Energy (EoE) ๋ฉํธ๋ฆญ์ ํ์ฉํ์ฌ ํจ์จ์ ์ธ ์๋์ง ์๋ชจ๋ฅผ ์ํ ์ ์ก ํ๋ผ๋ฏธํฐ๋ฅผ ์ ํํ๋ค. ์ฐ๋ฆฌ๋ EoE ๊ธฐ๋ฐ์ผ๋ก ์ ํํ ์ ์ก ํ๋ผ๋ฏธํฐ์ ํจ์จ์ฑ์ ๋ถ์ํ๊ณ , ๊ด๋ฒ์ํ ์คํ์ ์งํํ๋ค. ๊ฒฐ๋ก ์ ์ผ๋ก, NbADR์ ๊ธฐ์กด์ ADR ๋ฉ์ปค๋์ฆ๋ค๊ณผ ๋น๊ตํ์ฌ ์๋์ง ํจ์จ์ฑ ์ธก๋ฉด์์ ํจ๊ณผ์ ์ด๋ค. ์ถ๊ฐ์ ์ผ๋ก, NbADR์ ๊ธ๊ฒฉํ๊ฒ ๋ณํํ๋ ์ฑ๋ ํ๊ฒฝ์์LoRa ๋คํธ์ํฌ์ ์ฒ๋ฆฌ๋์ ๋ณด์ฅํ๊ณ ๋
ธ๋ ๊ฐ ๊ณตํ์ฑ์ ํฅ์์ํจ๋ค.Chapter 1 Introduction 1
Chapter 2 Related Work 4
Chapter 3 Preliminaries 7
3.1 LoRa/LoRaWAN 7
3.2 Transmission Parameters 8
3.3 ADR Mechanism 9
Chapter 4 Channel Modeling 10
4.1 Loss 10
4.2 Collision 12
Chapter 5 Node-based ADR Mechanism 14
5.1 Approach for Energy Efficiency 15
5.2 Node-based ADR Mechanism (NbADR) 17
Chapter 6 Evaluation 21
6.1 Simulation Settings 22
6.2 Simulation Results 23
Chapter 7 Conclusion 33
Bibliography 35Maste
Collision Avoidance Resource Allocation for LoRaWAN
Data Availability Statement: The data presented in this study are available on request from the
corresponding author.Funding: This research was partially funded by the Andalusian Knowledge Agency (project A-TIC-
241-UGR18), the Spanish Ministry of Economy and Competitiveness (project TEC2016-76795-C6-4-R)
and the H2020 research and innovation project 5G-CLARITY (Grant No. 871428).The number of connected IoT devices is significantly increasing and it is expected to reach
more than two dozens of billions of IoT connections in the coming years. Low Power Wide Area
Networks (LPWAN) have become very relevant for this new paradigm due to features such as
large coverage and low power consumption. One of the most appealing technologies among these
networks is LoRaWAN. Although it may be considered as one of the most mature LPWAN platforms,
there are still open gaps such as its capacity limitations. For this reason, this work proposes a
collision avoidance resource allocation algorithm named the Collision Avoidance Resource Allocation
(CARA) algorithm with the objective of significantly increase system capacity. CARA leverages the
multichannel structure and the orthogonality of spreading factors in LoRaWAN networks to avoid
collisions among devices. Simulation results show that, assuming ideal radio link conditions, our
proposal outperforms in 95.2% the capacity of a standard LoRaWAN network and increases the
capacity by almost 40% assuming a realistic propagation model. In addition, it has been verified
that CARA devices can coexist with LoRaWAN traditional devices, thus allowing the simultaneous
transmissions of both types of devices. Moreover, a proof-of-concept has been implemented using
commercial equipment in order to check the feasibility and the correct operation of our solution.Andalusian Knowledge Agency
A-TIC-241-UGR18Spanish Ministry of Economy and Competitiveness
TEC2016-76795-C6-4-RH2020 research and innovation project 5G-CLARITY
87142