A novel solution for energy-saving and lifetime-maximizing of LoRa wireless mesh networks

Figures & data

Figure 1. Overview of a LoRa WMN system deployed at Ton Duc Thang University.

Figure 2. Sensor node prototype.

Table 1. Computation of resistor values for $R_1$ and $R_2$.

$R_1(\mathrm{\Omega })$	$R_2(\mathrm{\Omega })$	$V_{\mathrm{out}}(V)$
10K	16.14K	3.3
10K	30K (')	5.0
10K	47.6K (”)	7.2

Figure 3. Procedure for a node joining the LWM network.

Figure 4. Diagram of the power control logic wiring.

Table 2. Power consumption of all devices for the first ES solution.

Devices	Mode	Work hour	Consumption	Voltage	Energy	Power	Total
ESP8266-12F	Deep sleep	3585 s	20 uA	3.3 V	18.41 nJ	66 uW/s	0.7 mW/h
	Wakeup	15 s	50 mA	3.3 V	11.00 mJ	0.165 W/s
SRF-05	Weakup	15 s	20 mA	5.0 V	6.67 mJ	0.1 W/s	0.4 mW/h
	Off	3585 s	0 mA	5.0 V	0.00  J	0 W/s
LoRa	Deep sleep	15 s	120 mA	5.0 V	40.00 mJ	0.6 W/s	2.5 mW/h
	Wakeup	3585 s	0 mA	5.0 V	0.00 J	0 W/s
HX711	Deep sleep	15 s	1 mA	5.0 V	4.40 uJ	66 uW/s	2.0 mW/h
	Wakeup	3585 s	0 mA	5.0 V	0.00 J	0 W/s
Measures	Hold current	3600 s	7.6 uA	8.4 V	17.73 nJ	63.84 uW/s	63.84 uW/h

Table 3. Power consumption of all devices for the second ESS solution.

Devices	Mode	Work hour	Consumption	Voltage	Energy	Power	Total
ESP8266-12F	Deep sleep	3599 s	20 uA	3.3 V	18.33 nJ	66 uW/s	0.11 mW/h
	Wakeup	1 s	50 mA	3.3 V	0.165 J	0.165 W/s
Measures	Hold current	3600 s	7.6 uA	8.4 V	17.73 nJ	63.84 uW/s	63.84 uW/h

Figure 5. Procedure for a node joining the LWM network.

Table 4. Comparison of the lifetime of popular batteries with the results of the other studies.

#	Power	Total consumption	Total	Power	Power via source	Energy-saving solution	Lifetime with energy-saving (days)	Lifetime without energy-saving (days)
1	(battery) 18650 $2200\times 4$ mAh	(max) 8.4V	4400 mAh	37 Wh; 1.5 W/day	35.7 Wh	ES	2 years, 8 months, 4 days	7
						ESS	3 years, 8 months, 2 days
2	(battery) 18650 5000×5 mAh	(max) 8.4V	10000 mAh	84 Wh; 3.5 W/day	81.1 Wh	ES	6 years, 1 month, 16 days	17
						ESS	8 years, 3 months, 28 days
3	(battery) 18650 $6800\times 4$ mAh	(max) 8.4 V	136000 mAh	114 Wh; 4.7 W/day	35.7 Wh	ES	8 years, 7 months, 21 days	23
						ESS	11 years, 3 months, 18 days
4	(accumulator) 6.6 V $5000\times 1$ mAh	(max) 6.8 V	5000 mAh	34 Wh; 1/4 W/day	32.8 Wh	ES	2 years, 5 months, 15 days	7
						ESS	3 years, 3 months, 13 days
5	(battery) AA $3000\times 4$ mAh	(max) 4.5 V	3000 mAh	13.5 Wh	13.5 Wh	ES	1 year, 4 days	3
						ESS	1 year, 4 months, 5 days

Figure 6. Performance of LoRa mesh nodes in terms of response time.

Figure 7. Packet loss (%) performance of LoRa mesh nodes.

Figure 8. Energy consumption measurements for the proposed two solutions.