Energy-efficiency approach for long range wireless communication

I value.This optimal function described in detail
 mented by The Things Network described as Figure 2. as Figure 3.
 The ADR algorithm only focused on parameters such The function added to the ADR algorithm right after
 as signal-to-noise (SNR), demodulation floor, and increasing the data rate step to make sure the output
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 Figure 1: ADR implementation of The Things Network 7.
 only affected to the transmission power. The ADR al- ues reflect the level of energy consumption of the end
 gorithm operational diagram was updated as Figure 4. devices.
 Evaluation of the proposed solution. • The formula to convert energy from (dBm) to
 In the LoRaWANTM specification for different fre- (W):
 quency bands, there was a separate transmission
 power range. In this research, we used the Europe fre-
  
 quency band, which included eight levels of transmis-
  
 sion power. The specification 9 defined the transmis-    
 PdBm  P − 30
 sion power as below:  (dBm)  (2)
 10 10 10
 P = 1W × = 10
 [0, 2, 4, 6, 8, 10, 12, 14, 16](dBm) (1) (w) 1000
 Formulas (2) and (3) were used to calculate the • The formula to convert from energy (W) to cur-
 strength of an electric current in amperes; these val- rent intensity (A):
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 Figure 2: ADR algorithm of The Things Network 7.
 Table 2: Energy Saving Levels
 Energy Saving Energy Saving
 P(W)
 IA = (3) Level
 V(V)
 dBm Watt mA (3.3V)
 Based on two conversion formulas, together with
 1 2 ≈ 0.00158 ≈ 0.48
 eight transmission power levels of the ADR feature,
 ≈ ≈
 the energy-saving levels of the optimal function de- 2 4 0.00251 0.76
 scribed in Table 2. 3 6 ≈ 0.00398 ≈ 1.20
 The energy-saving levels calculated in Table 2 showed 4 8 ≈ 0.00631 ≈ 1.90
 that the energy consumption determined by the trans-
 5 10 ≈ 0.01000 ≈ 3.00
 mission power parameter of the LoRaWANTM was
 relatively high. The energy could save up to 7.6 mA at 6 12 ≈ 0.01585 ≈ 4.80
 3.3 voltage, which could extend a significant amount 7 14 ≈ 0.02512 ≈ 7.60
 of battery life for the end devices.
 EXPERIMENTAL RESULTS LoRaTM infrastructure.
 In this section, We introduced a LoRaTM infrastruc- In this paper, we constructed a simple wireless sensor
 network, which used LoRaTM to transmit data. The
 ture used for conducting experiments. These exper-
 system infrastructure in Figure 5 included four com-
 iments helped to evaluate the efficiency of the pro-
 ponents:
 posed solution.
 • An air quality sensor.
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 Figure 3: Optimal function for ADR algorithm.
 • A gateway device. • Grove - Laser PM2.5, an air quality sensor from
 • A LoRaTM network server. Seed.
 • S76SXB, a LoRaWANTM certified module.
 • A data analysis application.
 • A 3.7V 2000mAh Lithium-Ion battery.
 In this system, We developed the air quality sensor The gateway structure outlined in Figure 7, which
 and the gateway by using open and easily accessible constructed by a combination of a Raspberry Pi 3
 hardware accompanying with open-source software. Model B+ with a RAK831 LoRaTM gateway module.
 The network server and the application server also The network server and application server deployed
 built with renown open-source frameworks to easy on on cloud computing service of Digital Ocean. The
 development and deployment. network server was running framework The Things
 The air quality sensor shown in Figure 6, which in- Network with LoRaWANTM version 1.1.
 cluded hardware components as following:
 Device configuration.
 • MSP430FR5994, an ultra-low-power MCU In the experiment section, the study wanted to focus
 from Texas Instruments. on assessing energy optimization capabilities, as well
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 Figure 4: Optimal function for ADR algorithm.
 Figure 5: The LoRaTM infrastructure overview.
 as finding out the limitations of the proposed solution. • Automatically join the network via over-the-air-
 The LoRaTM gateway and the air quality sensor in the activation (OTAA) mechanism.
 experiments configured as follows: • Operation on 867.5 MHz frequency band.
 The gateway located 20 meters above the ground and
 • Initial spreading factor (SF) at 12.
 connected to the internet via Wi-Fi. This device con-
 • Initial transmission power at 16 dBm.
 figured to operate on eight channels of EU868MHz
 frequency band in Table 3. • Enabled adaptive data rate feature.
 The air quality sensor was set up with the following • Sending air data with the un-confirm configura-
 information: tion.
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 Figure 6: The air quality sensor structure.
 • Powered by a 3.7V - 2000 mAh Lithium-Ion bat-
 tery.
 Experiments
 Experiment 1
 The goal of this work measured and compared the
 power consumption of the proposed solution and
 original algorithm of The Things Network in short-
 range. The result presented in Figure 8.
 Figure 7: The LoRaTM gateway.
 Table 3: The configuration channel of the gateway
 Channel Num- Bandwidth Frequency
 ber
 1 125kHz 868.1 MHz
 2 125kHz 868.3 MHz
 Figure 8: The result of experiment 1.
 3 125kHz 868.5 MHz
 4 125kHz 867.1 MHz
 5 125kHz 867.3 MHz Based on the results of the experiment, the following
 6 125kHz 867.5 MHz assessments concluded:
 7 125kHz 867.7 MHz • The battery life of the sensor with the proposed
 8 125kHz 867.9 MHz solution was 4 percent longer than the original
 algorithm.
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 • Themount a of data received at the gateway was
 also more than 4 percent corresponding to the
 lifetime.
 • The loss rate was utterly equivalent to the origi-
 nal algorithm.
 • The transmission power difference could reach
 up to 14 dBm, according to the evaluation, it
 saved 7.6 mA per transmission.
 Experiment 2
 The second experiment aimed to evaluate the pro- Figure 10: The result of experiment 3.
 posed solution within medium range in the city en-
 vironment. The result illustrated in Figure 9.
 • Implemented in the network server, so there was
 no limit on the end devices.
 • The solution only optimizes energy consump-
 tion, did not affect the transmission quality and
 the loss rate.
 • In the experiment, the saving-power could be up
 to 14 dBm per transmission, and this could ex-
 tend the battery life of the end device to 4 per-
 cent.
 • High applicability, because of requiring no
 Figure 9: The result of experiment 2. hardware changes and some minor updates in
 software.
 • There was some limitation of the proposed so-
 Based on the experimental result , we stated some in- lution. We summarized as below:
 formation: • Apply more excellent techniques (machine
 • In the medium range, the solution still able to learning, big data) to be able to find the most
 save energy but with a few amounts of energy. optimal transmission power level with the least
 • The transmission power saved by the solution uplink package, to limit the number of down-
 was 2 dBm. links to save more energy.
 • The optimal function reduced power transmis-
 Experiment 3 sion step by step, so it required more downlink
 to control the transmission parameters on the
 The third experiment explained to the efficiency ofthe
 end devices.
 solution within a long-range. The result described in
 Figure 10. • This solution required the end devices enabled
 With the result from experiment 3, we had a conclu- the adaptive data rate feature.
 sion that the proposed solution did not affect the com- • The solution built on the foundation of
 munication range of the end devices. The distance LoRaWANTM network protocol so that it
 map displayed in Figure 11. applied to LoRaTM systems only.
 DISCUSSION
 The paper studied and proposed a solution to opti-
 mize energy consumption in the wireless sensor net- CONCLUSIONS
 work using LoRaTM technology and LoRaWANTM
 network protocol. The study also introduced a typical In this paper, we proposed an adaptive algorithm
 LoRaTM infrastructure with components: air qual- to save energy consumption of a LoRa-based system
 ity sensor, gateway, network servers, and application while keeping communication quality unchanged.
 server. From the result of experiments, there were The best point of the solution was studying and devel-
 some advantages as below: oping based on the LoRaWANTM network protocol
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Science & Technology Development Journal – Engineering and Technology, 3(SI1):SI59-SI70
 Figure 11: The distance map in experiment 3.
 so it could be expanded and improved without limita- idea and structure of the paper. Tran Ngoc Thinh
 tion on any hardware. Based on the limitations, some checked the algorithm and verify the experiments. All
 further research directions may be conducted to op- authors wrote and proof-read.
 timize the current solution, for example using addi-
 tional sensitivity information of the gateway to opti- REFERENCES
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 IP: Internet protocol for LoRaWAN-based Infrastructure. IEEE 5th International Con-
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 7. Adaptive Data Rate;Available from: 
 AUTHORS’ CONTRIBUTIONS org/wiki/LoRaWAN/ADR.
 Le Cong Nga proposed the algorithm and implement
 the experiments. Cuong Pham-Quoc proposed the
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 8. How does RSSI (dBm) relate to signal quality (percent);Available 9. LoRaWANTM Specification version 1.1. 2017;Available
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 relate-to-signal-quality-percent-439. specification-v11.
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Tạp chí Phát triển Khoa học và Công nghệ – Kĩ thuật và Công nghệ, 3(SI1):SI59-SI70
 Open Access Full Text Article Bài Nghiên cứu
Giải pháp tiết kiệm năng lượng cho công nghệ giao tiếp không dây
tầm xa
Lê Công Ngà, Phạm Quốc Cường*, Trần Ngọc Thịnh
 TÓM TẮT
 Theo các nghiên cứu gần đây, mạng cảm biến không dây (Wireless Sensor Network) tiêu thụ năng
 lượng thấp sẽ ngày càng trở nên phổ biến, thúc đẩy xu hướng nghiên cứu về tối ưu hoá năng lượng
 Use your smartphone to scan this
 cho mạng cảm biến không dây tăng nhanh. Công nghệ LoRaTM là một công nghệ điều chế sóng
 QR code and download this article mang đến khả năng truyền tải dữ liệu ở khoảng cách xa với mức yêu cầu năng lượng thấp, thêm
 vào đó LoRaWANTM là một giao thức mạng dựa trên công nghệ LoRaTM được thiết kế nhằm ưu
 hoá cho các thiết bị hoạt động dựa trên nguồn năng lượng là pin. Hai công nghệ này được đánh
 giá là giải pháp phù hợp cho mạng cảm biến không dây, giúp giảm mức năng lượng tiêu thụ và
 mở rộng tầm hoạt động. Trong thời đại hậu máy tính cá nhân, khi các thiết bị chủ yếu sử dụng
 pin thì việc tiết kiệm năng lượng là một trong những yếu tố rất quan trọng và hấp dẫn người sử
 dụng. Trong bài báo này, chúng tôi nghiên cứu về kỹ thuật thích ứng trong thiết lập các thông số
 truyền tải dữ liệu của mạng LoRaTM và đề xuất một giải pháp tiết kiệm năng lượng cho giải thuật
 thích ứng. Giải thuật của chúng tôi giúp tiết kiệm năng lượng nhưng vẫn giữ nguyên chất lượng
 truyền dẫn theo giao thức LoRa. Nghiên cứu này giới thiệu một phần cứng mẫu của một nút cảm
 biến trong mạng cảm biến không dây, cũng như hiện thực một hệ thống mạng LoRaTM điển hình.
 Chúng tôi tiến hành ba thí nghiệm khác nhau với các cảm biến chất lượng không khí và các bo
 mạch MCU của hãng Texas instrument. Các thí nghiệm của chúng tôi được tiến hành với hệ thống
 thực và mô phỏng đều cho kết quả tốt với tối thiểu 4% năng lượng được tiết kiệm. Mặc dù tiết
 kiệm năng lượng nhưng chất lượng truyền dẫn về khoản cách và tỉ lệ gói tin đến đều được giữ
 nguyên. Các hệ thống thực nghiệm và giải thuật có thể được dùng cho các nghiên cứu khác cùng
 chủ đề. Ngày nay, càng tiết kiệm năng lượng sẽ càng làm cho thế giới xanh hơn.
 Từ khoá: LoRaTM, LoRaWANTM, Mạng Cảm Biến Không Dây, Tốc Độ Dữ Liệu Thích Ứng, Tiết Kiệm
 Năng Lượng
 Trường Đại Học Bách khoa – Đại học
 Quốc Gia Thành Phố Hồ Chí Minh
 Liên hệ
 Phạm Quốc Cường, Trường Đại Học Bách
 khoa – Đại học Quốc Gia Thành Phố Hồ Chí
 Minh
 Email: cuongpham@hcmut.edu.vn
 Lịch sử
 • Ngày nhận: 05-8-2019
 • Ngày chấp nhận: 03-9-2019 
 • Ngày đăng: 13-11-2020
 DOI :10.32508/stdjet.v3i3.532 
 Bản quyền
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 mở được phát hành theo các điều khoản của
 the Creative Commons Attribution 4.0
 International license.
 Trích dẫn bài báo này: Ngà L C, Cường P Q, Thịnh T N. Giải pháp t iết kiệm năng l ượng cho công nghệ 
 giao t iếp không dây t ầm xa. Sci. Tech. Dev. J. - Eng. Tech.; 3(SI1):SI59-SI70.
 SI70