Optimizing the Performance of Pure ALOHA for LoRa-Based ESL

Khan, Malak Abid Ali; Ma, Hongbin; Aamir, Syed Muhammad; Jin, Ying

doi:10.3390/s21155060

Cited by 21 publications

(9 citation statements)

References 26 publications

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“…Thong et al [ 77 ] and Cook et al [ 78 ] suppose that a QR code-based system may be used for telemedicine services only. Khan et al [ 79 ] argues that it may be functional only for needs of distant work to ensure uninterrupted processes. Wolfgang Sassin [ 33 , 80 ] and Oleg Donskikh [ 76 ] admit the effectiveness of a QR code-based system for the control of transboundary relocation and its awkwardness in use within a country’s borders.…”

Section: Resultsmentioning

confidence: 99%

Public Policy Measures to Increase Anti-SARS-CoV-2 Vaccination Rate in Russia

Boguslavsky

Шарова

Sharov

2022

IJERPH

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The total vaccination rate remains relatively low in Russia as of March 2022 (around 55%, with around 20% in some regions). In the paper, we study the reasons for it. We communicate the results of our survey aimed at detecting reasons for the relatively low anti-SARS-CoV-2 vaccination rate in Russia (47.1% as of mid-January 2022) and suggest potential measures to increase the level of confidence in the Russian vaccination campaign. A total of 14,310 users exhibited interest to participate in the research (16.84% of the total number of invitations sent in the Russian social network VKontakte). After the sample set repair, only 5822 (40.68% of those who agreed to participate) responses were suitable for the research, and they composed the final set. The age range of the respondents was 16–51 years old (y.o.) with a mean of 29.1 ± 10.6 y.o. The proportion of the female gender in responses was 44.23%. A total of 2454 persons (42.15%) expressed their hesitant, cautious, or negative attitude towards vaccine uptake. Of the 2454 persons with cautious attitude towards vaccination, only 928 (37.82%) were concerned about the quality of the Russian vaccines. A total of 1323 individuals (53.91%) supported one or more conspiracy beliefs. A total of 5064 (86.98% of the whole set) showed cautious or negative attitude towards the planned introduction of a nationwide system of vaccination certification/verification based on QR codes. The main social factors that hinder the Russian vaccination campaign are: vexation over the lack of desire of officials to receive feedback from the general population regarding vaccination, wide support for conspiracy beliefs, and controversy over the QR code-based digital system. To elevate the vaccination rate in Russia, the following steps may be taken: social encouragement of those who support vaccination, increase in transparency of the vaccination campaign, acceptance of both digital and paper vaccination certificates, increase in participation of society in vaccination-related discussions, public disclosure of vaccine composition, and avoidance of excessive digitalization of data in the vaccination campaign.

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Section: Resultsmentioning

confidence: 99%

Public Policy Measures to Increase Anti-SARS-CoV-2 Vaccination Rate in Russia

Boguslavsky

Шарова

Sharov

2022

IJERPH

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“…Currently, a random access approach similar to the pure ALOHA protocol is used in LoRaWAN. However with pure ALOHA, the maximal channel utilization is only 18.4% [7] and dealing with collisions is an important task in current LoRaWAN. One solution is to transmit acknowledgments if messages are received correctly.…”

Section: Lorawan Channel Accessmentioning

confidence: 99%

“…This setup theoretically allows slotted ALOHA to reduce the number of collisions as well as the vulnerable time by 50% when compared to pure ALOHA [8]. Furthermore, the maximum channel utilization is increased to 36.8% [7]; however, accurate timing information and resynchronization is required to keep devices aligned to the time slots and clock inaccuracies resulting in clock drifts must be taken into consideration. This is dealt with by using an appropriate slot length and additional guard times to compensate slight inaccuracies.…”

Section: Slotted Alohamentioning

confidence: 99%

Towards LoRaWAN without Data Loss: Studying the Performance of Different Channel Access Approaches

Loh

Mehling

Hoßfeld

2022

Sensors

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The Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access protocols. It operates in the license free 868 MHz band and gives everyone the possibility to create their own small sensor networks. The drawback of this technology is often unscheduled or random channel access, which leads to message collisions and potential data loss. For that reason, recent literature studies alternative approaches for LoRaWAN channel access. In this work, state-of-the-art random channel access is compared with alternative approaches from the literature by means of collision probability. Furthermore, a time scheduled channel access methodology is presented to completely avoid collisions in LoRaWAN. For this approach, an exhaustive simulation study was conducted and the performance was evaluated with random access cross-traffic. In a general theoretical analysis the limits of the time scheduled approach are discussed to comply with duty cycle regulations in LoRaWAN.

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“…In addition, the orthogonality of different SFs can avoid interference among them [ 5 , 6 ]. Moreover, the theoretical Frame Success Rate (FSR) for Pure ALOHA, which is constantly employed in LoRa systems, also depends on the SF, the number of LoRa devices, and the duty cycle [ 7 ]. In Pure ALOHA, the LoRa devices access the channel randomly [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Combinatorial MAB-Based Joint Channel and Spreading Factor Selection for LoRa Devices

Urabe

Fujisawa

et al. 2023

Sensors

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Long-Range (LoRa) devices have been deployed in many Internet of Things (IoT) applications due to their ability to communicate over long distances with low power consumption. The scalability and communication performance of the LoRa systems are highly dependent on the spreading factor (SF) and channel allocations. In particular, it is important to set the SF appropriately according to the distance between the LoRa device and the gateway since the signal reception sensitivity and bit rate depend on the used SF, which are in a trade-off relationship. In addition, considering the surge in the number of LoRa devices recently, the scalability of LoRa systems is also greatly affected by the channels that the LoRa devices use for communications. It was demonstrated that the lightweight decentralized learning-based joint channel and SF-selection methods can make appropriate decisions with low computational complexity and power consumption in our previous study. However, the effect of the location situation of the LoRa devices on the communication performance in a practical larger-scale LoRa system has not been studied. Hence, to clarify the effect of the location situation of the LoRa devices on the communication performance in LoRa systems, in this paper, we implemented and evaluated the learning-based joint channel and SF-selection methods in a practical LoRa system. In the learning-based methods, the channel and SF are decided only based on the ACKnowledge information. The learning methods evaluated in this paper were the Tug of War dynamics, Upper Confidence Bound 1, and ϵ-greedy algorithms. Moreover, to consider the relevance of the channel and SF, we propose a combinational multi-armed bandit-based joint channel and SF-selection method. Compared with the independent methods, the combinations of the channel and SF are set as arms. Conversely, the SF and channel are set as independent arms in the independent methods that are evaluated in our previous work. From the experimental results, we can see the following points. First, the combinatorial methods can achieve a higher frame success rate and fairness than the independent methods. In addition, the FSR can be improved by joint channel and SF selection compared to SF selection only. Moreover, the channel and SF selection dependents on the location situation to a great extent.

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Optimizing the Performance of Pure ALOHA for LoRa-Based ESL

Cited by 21 publications

References 26 publications

Public Policy Measures to Increase Anti-SARS-CoV-2 Vaccination Rate in Russia

Public Policy Measures to Increase Anti-SARS-CoV-2 Vaccination Rate in Russia

Towards LoRaWAN without Data Loss: Studying the Performance of Different Channel Access Approaches

Combinatorial MAB-Based Joint Channel and Spreading Factor Selection for LoRa Devices

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